Still much to learn with Part L

Building designers and contractors are now starting to realise the implications of Part L of the Building Regulations introduced in 2000, and the impact it has on building projects. Trying to find the most effective means of monitoring energy usage has always been one of the challenges. While the guidelines state that 90% of all energy use must be accounted for, it does not state how energy measurements should be collected. Alan Roadway of ABB provides advice on the benefits of employing meters to measure electricity usage, and addresses the implications of not fulfilling Part L.

The purpose of Part L is to encourage industry-wide adoption of energy-efficient practices in building design and construction. Its aim is to reduce carbon emissions; one of the main factors contributing to global warming. The Government wants more businesses to reduce the amount of power used for operating a building, while also reducing the energy lost from buildings.

The guidelines state that all new buildings must conform to the regulations, with the ability to measure 90% of fuel consumed by a building integral to complying. In addition, sub-meters should be placed in buildings that are bigger than 500m_. Meters, such as those from ABB's Delta Plus range, can help fulfil electricity measuring requirements.

While the regulations affect the private sector and public sector alike, the importance of Part L on public sector buildings, such as hospitals, has taken on added significance when taking the Private Finance Initiative (PFI) into account. Private contractors developing new hospital buildings can benefit from the measures required by Part L, by employing the information provided by energy meters effectively.

Under PFI, contractors building the hospital facilities cover the construction costs, then lease the buildings to the hospital trust for over a specified period of time. Metering electricity, in turn, helps them to accurately measure and control costs throughout a hospital's facilities.

Using these readings, contractors can ensure that the right amount of electricity is being consumed in appropriate areas of a building. Meters will help users identify areas of high usage, including those where excessive power is being used, and also identify any areas with spare capacity. This enables contractors to ensure that within a certain location, such as the X-ray unit where power requirements may be high, the right amount of power to support that facility is being allocated. It also allows contractors to accurately charge bills to any franchises located in the hospital, as meters can show the amount of power consumed in the rented space.

While individual meters vary, they can typically read Kwh, amps, voltage, power factor, and reactive power usage. Some meters, like ABB's Delta single meter, have additional functions such as pulse output, or infra-red interfaces. These additional functions enable users to employ a central system to monitor power consumption; and readings can be measured down to the minute, hour or day.

While there is a small increase in the initial costs involved in complying with Part L, such as buying energy meters, it does have longer-term benefits. Developers can use the readings from the meters to help forecast costs and allocate resources on future developments.

The use of energy meters means that a company can also reduce building running costs. While exact savings will differ according to the size and type of construction, companies that act upon the results given by meters typically save 20-25% costs on commercial buildings and 10-15% in industrial facilities. By using the information provided by the energy meters effectively, owners can cut down on waste and re-allocate energy limits in different parts of a building.

To ensure compliance with Part L, construction companies must include in the planning documents submitted to the local council how they will measure 90% of energy used in a building. This now needs to be outlined before work can begin. Not conforming to Part L regulations can lead to numerous fines for the developer or contractor. They can reach up to £5000 for contravening the initial notice, and an additional £50 for every day that the contravention continues. A local authority can also serve an enforcement notice for any installation that contravenes the regulations to be altered or removed. If the owner does not comply with the notice the local authority has the power to undertake the work itself and recover the costs of doing so from the owner.

Approached in the right way, Part L can actually provide benefits for contractors. Metering can provide accurate measurements of power consumed during the construction project and whilst in operation, and helps to identify accurate costings for future projects. For a building's owner they will also provide readings of power consumption to help to identify areas where money can be saved.

SiP Conference celebrates Partner Success

ABB's 2008 Strategic Partner Conference celebrated the success of ABB's Low Voltage Products division, with 28 of its current Strategic Industrial Partners (SiP) in attendance for the conference in Edinburgh. The conference was chaired by the UK Industrial Sales Manager, Simon Marsh, accompanied by three guest speakers, ABB's Head of Automation Products division, Ian Rennie, General Manager for ABB's Low Voltage Products division, James Haigh and Finnish Switch Factory representative, Ari Yrjanainen.

The aim of the day was to inform the strategic partners about the progress made by ABB within the Low Voltage arena and to thank them for their continued support and development in 2007. Attendees heard about the changes made within the division and the financial revue of 2007. It was reported that growth in Low Voltage Products was above all expectations with ABB's SiP's achieving over 23 per cent of the total growth, well above expectations.

Speaking at the conference, James Haigh, General Manager for ABB's Low Voltage Products division thanked all of the Strategic Partners for their continued support and dedication to the ABB Brand. Ian Rennie, Head of ABB's Automation Products division then provided a presentation showing how the growth throughout the ABB brand was not just limited to Low Voltage Products or the UK, but across all entities around the world.

SiP and Sales Manager of Western Electrical, Dave Boyle, commented on the conference, "In reference to the conference, I would like to thank ABB and all of its colleagues for organising a very well run event. I found both days were very informative whilst still maintaining an element of fun! It was good to see that ABB, just like Western Electrical, are positive, up-beat and excited about out future business relationships."

Mr Boyle, continued, "It was also very refreshing to hear one of our own suppliers addressing the problem of mistakes made in the past and explaining how we can correct them. Well done to you all, and good luck for 2008."

A selection of ABB's partners were also presented with awards, celebrating their success over the past 12 months. The winners included Buckinghamshire-based Industrial Electrical Distributor, CSE for Best Strategic Partner for Turnover; Best Strategic Partner for Growth was awarded to Western Electrical, the largest independent electrical wholesaler in the South West; whilst the most new product lines stocked was awarded to Electrical Wholesalers, Premier Electrical.

The final accolade for most usage of business online went to Ryan Reilly of Alex Nangle – an independent family run company specialising in Low Voltage and Medium Voltage equipment for industrial and commercial markets.

ABB's Strategic Industrial Partnership is a nationwide network of distributors committed to providing their customers with an unparalleled level of service and support for ABB's low voltage products. Each partner has the know-how to advise on all technical, commercial and logistical matters and can support ABB's full range of industrial low voltage products available in the UK market. The network is currently made up of 30 partner locations strategically situated around the UK to ensure that the products and support are always available locally.

New range of ABB operator panels offer improved control

ABB has introduced a new range of control panels for its AC500 PLCs, providing operators with a clear and easy to use method of controlling any automated process. Available in various options, the range of CP400 operator terminals provide immediate access to a wealth of data, enabling users to better manage operating conditions.

The CP400 range offers the ideal human machine interface (HMI), by providing enhanced transparency and efficiency in automated processes. The CP400 is currently available in several models, ranging from the standard CP410 through to the large-screen CP450, which features a colour touch screen. Depending on the model selected, the CP400 range delivers highly efficient functionality such as alarm and event management, graphics animation, Macro and Ladder Diagram functionality and multi-language displays (up to five languages).

Users can quickly view and easily manage project components using the screen manager – available as a detailed list or screen miniatures. They can also simplify the creation of any project by using the Macro and Ladder functions, providing ready-to-use modules such as arithmetic functions. Available with on and offline simulations, the CP400 can be used to test projects, screens and alarms as well as check communications and controller functions before starting a process. This helps manufacturers save valuable time on testing and commissioning.

Offering easy programming and quick configurations, the control panels offer solutions for any application area helping to facilitate plant decisions.

All CP400 models can be connected to a printer, keyboard or modem and are fitted with a 32-bit RISC processor and 4Mb of flash memory enabling it to be used in large control projects and data management applications. The control panels can also communicate with other ABB controllers, including the AC31 and AC500, as well as all major PLCs. The available back-lit displays range from a compact three-inch monochrome display up to a large size, 10.4-inch, TFT colour display with 65,000 colours.

For additional security, the CP400 enables users to protect their files and machine configurations using global and object-specific passwords, with up to nine protection levels, to prevent unauthorised downloading of application data.

ABB's Triline-R enclosure system helps APD improve productivity with faster delivery times

UK-based electrical manufacturer and ABB approved system builder, APD Ltd, has halved the time it takes to specify and assemble mains distribution boards by building its systems around ABB's new Triline-R enclosure system. Reducing delivery times from 8-10 weeks down to 4-5, the Triline-R system features a unique modular construction that provides full access to the complete range of products required for mains distribution.

With most of the components pre-installed, the Triline-R range enables APD to realistically deliver mains boards to their customers within just a few weeks after placing the order with ABB. "Before we used the Triline-R range, it could take up to a week to get a quote on a similar product order. Now, we can turnaround a quote within a day and an entire project in five weeks. This has ensured significant reductions in delivery times and improvements in sales and levels of productivity," commented Paul Philpott, Sales and Engineering Manager at APD Ltd.

The full Triline range of cabinets and distribution boards offers manufacturers the choice of breakers, switches, fuse gear and line protection devices whilst ensuring optimum safety and functionality for low-voltage switchgear assemblies. With all additional components set up to 'plug and play' even complex projects can be assembled and delivered in a fraction of the time.

Further enhancing the ease-of-use and flexibility for easy configuration, ABB has produced the Panel Design Configurator (PDC) software tool, to enable panelbuilders to configure a board themselves. Available free to panelbuilders, it includes a parts list, circuit diagrams and a graphical representation of the front view of the distribution board.

Using the software, panelbuilders can now select and plan their boards, and choose the parts required. Parts can be dragged and dropped onto the front view image to check compatibility. They can then be placed onto an order form and sent to ABB. The PDC software also provides panelbuilders with the flexibility to export data and parts lists to other Windows programs. It can also be used for project planning purposes, by providing a facility where customer data can be stored alongside build projects.

Mr Philpott, continues, "Offering the Triline-R range has enabled APD Ltd to expand its current product offerings. We have been able to win new business and hold onto customers who are attracted by a quick turnaround and high quality levels of the product. We have supplied switchboards in the past, but Triline-R provides a great modular system that is much easier for us to configure and deliver."

Commenting on ABB's partnerships, Kevin Lenton, Application Engineer for ABB said: "ABB is working concurrently with its panelbuilders to provide the most effective and timely solution to the market. Through product specialists and managers covering all aspects of electrical distribution and motor control technical advice, we offer a unique product and support package. We look forward to working, and continuing to move forward, with our new partners."

The Triline-R enclosure has been designed to provide maximum flexibility for the installation of circuit breakers and other components. Plug-in module plates can be used to install Moulded Case Circuit Breakers (MCCBs) and switch fuses horizontally for when space is at a premium. Compartments and busbars can be ordered to suit requirements. Triline also provides flexible incomer options; from either the top or bottom of the enclosure, to suit the direction of incoming power cables.

Second winner revealed in ABB's High Performance Van Draw

The second winner of ABB's High Performance van giveaway promotion has now been announced. David Jackson from DJ Jackson electrical contractors was recently presented with the keys to a brand new Volkswagen Caddy van by Reeve Carter, Sales Manager, ABB low voltage products.

Jackson was entered into the prize draw when he purchased ABB Housemaster Compact consumer units from WF Wades, Norwich.

Says Jackson: "I'm very surprised and pleased to have won. I stock around 30 of ABB's Housemaster Compact consumer units on my shelves at any one time. The product is great and the ABB Housemaster is now one of my preferred choices for consumer units."

The presentation of the second van marks the close of ABB's High Performance promotion, which has been running since 2006 to help build awareness of the Housemaster Compact amongst both contractors and wholesalers.

"Partnering with Volkswagen for this campaign gave us an attention-grabbing way of drawing attention to the virtues of the Housemaster Compact amongst our target audience," says James Haigh, General Manager for ABB's low voltage product business. "The prize of a Volkswagen Caddy van was a good way of underlining the quality and reliability messages that we are keen to promote for the Housemaster Compact."

Ideal for domestic and commercial new-builds and retrofit installations, the Housemaster Compact offers a number of features aimed at simplifying both installation and operation.

The vertically sliding door of the Housemaster slides back into the unit housing, enabling it to be fitted in even cramped locations. Extra space for cables within the unit has been made by reducing the size of the internal components such as the MCBs. The unit offers a flexible split load that has added protection and isolation capabilities.

Essential circuits such as lighting are fed by a main isolating switch; other circuits are protected with residual current devices (RCD). Separate MCBs can be assigned to other devices to protect against any electrical faults without disturbing all the power which is distributed around the building. Non-standard configurations can also be accommodated. A fully shrouded busbar enables the unit to be installed quickly and easily and also provides protection when it is in operation.

The Housemaster Compact is available from wholesalers throughout the UK. For details of your nearest stockist, please call 0800 269 371, ref. 'Housemaster Compact'.

ABB signs electrical distributors as front line strategic partners

ABB has appointed Buckinghamshire-based CSE Industrial Electrical Distributors and Nottingham-based electrical distributors TLA UK at the front line of its Strategic Industrial Partner (SIP) channel for industrial and automation products. Under the banner of "Strategic Industrial Partner +" these distributors have been selected by ABB on the basis of their extensive stock of ABB products and commitment to the ABB brand.

Any customer that buys ABB products through a Plus status partner will receive full technical support from ABB and be kept up to date on new ABB products. Simon Marsh, manager for ABB's Strategic Industrial Partner network, explains the significance of the Plus status; "The plus partners are effectively hubs for ABB stock in the UK. Each plus distributor has committed to a comprehensive ABB stock package to provide instant availability to customers and the same high level of service as demonstrated by ABB."

Plus partner distributors have full view of the ABB stock holding in the UK and can provide quick turnaround of items they may not have in stock. TLA's technical expertise and strength in customer service and support were key factors in it being awarded the coveted plus status. "Like CSE, TLA has a good technical awareness of ABB's products and high quality of service levels" explains Marsh. "Both distributors are proven to have strong technical internal telephone and logistics support in addition to sales engineers available to assist customers with their requirements on a daily basis".

Established in 1988, TLA has grown to become one of ABB's key partners, serving panel-builders and OEMs in the East Midlands. To support its Partner Plus status TLA is expanding its warehouse capacity by almost 100% increasing floor space from 330,000 square feet to over 600,000 square feet. This means that TLA will be able to hold an increased range of ABB stock including products from its automation, instrumentation and cable accessories product categories. It will also carry a broader selection of low voltage products including switchgear and enclosure product ranges.

CSE has been an official distributor of ABB products since 1971 and has developed an affinity with the complete range through long association. With a comprehensive ABB stockholding already in place, CSE was an obvious choice for the Plus status. ABB's faith in CSE has been continuously repaid as CSE at Bourne End in Bucks have topped the league table of SIPs since the channel was introduced.

ABB's Strategic Industrial Partnership is a nationwide network of distributors committed to providing their customers with an unparalleled level of service and support for ABB's low voltage products. Each partner has the know-how to advise on all technical, commercial and logistical matters and can support ABB's full range of industrial low voltage products available in the UK market. The network is currently made up of 30 partner locations strategically situated around the UK to ensure that the products and support are always available locally.

Compact softstarter range launched by ABB

ABB has expanded its softstarter range with the launch of a compact version for small to medium sized motors. Designed for motor currents from 3 to 45A, and motor voltages of up to 600V, the PSR compact softstarter complements ABB's existing PSS and PST ranges for applications from 3A to 1050A.

Available through ABB's Strategic Industrial Partner network, as well as existing softstarter alliance partners, the PSR provides a compact device for OEMs and panelbuilders serving the food and beverage, process and automation and water treatment industries.

The PSR softstarter is available in three physical sizes and nine current ratings, with widths ranging from 45mm to 54mm, making it suitable for installation in confined spaces. To help simplify installation, the PSR can be either screw-fitted or mounted onto DIN rails.

Ideal for pump, fan, mixer and conveyor applications, the PSR Softstarter range is designed to minimise starting currents and reduce the risk of current spikes in small to medium-sized motors. This helps to minimise the impact of motor starting on the electrical network and also prolongs the life of mechanical components.

As well as standard indicator lights showing operational status, PSR softstarters also offer several indicator and control possibilities. Three potentiometers located on the front of the PSR, provide users with control over motor starting and stopping. Two of the potentiometers can each be set to control motor ramp up and ramp down times. This is particularly helpful for pump applications, where the gradual slow-down of the motor is required to prevent 'hammering'. A third potentiometer enables the user to set the initial voltage of the PSR softstarter required to start a motor.

Two types of signal relays are also supplied with the PSR softstarter. All three frame sizes have a run relay, which indicates that the PSR is running. In addition, the two larger-sized PSRs have a Top of Ramp (ToR) relay. The ToR indicates when a top speed has been reached so that the load can be switched on, useful for applications such as compressors where a motor needs to be up to speed before the load is applied. The PSR also benefits from having built in bypass contacts, which leads to reduced power losses whilst the motor is running at speed, and reduced heat build up.

The PSR range can manage ten starts per hour. If greater starting capacities are required, an auxiliary cooling fan is available, enabling starting capacity to be increased to 20 starts per hour.

The PSRs can also be controlled remotely with the addition of ABB's fieldbus plug, which enables simple and fast connection to any existing protocol in the FieldBusPlug range through an optional 'neutral' fieldbus-independent interface.

ABB add new features to PST Softstarter range

ABB has added two new features to its PST Softstarter range; torque control and analog output.

With torque control users can now select between normal voltage ramp and torque ramp for starting and stopping motors. By selecting the torque ramp for starting, the torque of the motor follows a predefined optimal curve. This ensures an even smoother start, leading to a more linear acceleration of the motor speed. For stopping motors using torque control, the voltage is adjusted so that the torque decreases from an operational level down to a value matching the pre-set end voltage, ensuring a smooth stop.

Torque control is especially useful for stopping pumps. Using the torque ramp a motor can now be brought almost to a complete stop without any water hammering or back-flow occurring.

A maximum torque level can also be set on start up using the softstarter. By setting a torque limit the potentially damaging effect on the motor is couplings or gearbox is minimised.

The PST softstarter is now also fitted with a programmable analog output signal, and can be set for a 0-10V, 0-20mA or 4-20mA output. The output readings that can be set represent motor current, motor temperature and main voltage. By having analog output available on the softstarter itself, users no longer need to use a separate current transformer to connect the panel meter.

The analog signal can be used to feed directly into an analog meter or a PLC. With analog output, users can more effectively monitor the softstarter's activities, such as motor current or power consumption monitoring.

ABB launches high performance MCB range

ABB has expanded its miniature circuit breaker range with a new high performance series aimed at industrial and commercial applications. Replacing the S500 series, the S800 series offers two levels of breaking capacities depending upon the application requirements.

The S800S is aimed at the industrial sector and provides breaking capacities up to 50kA, while the S800N is suitable for commercial applications and offers breaking capacities up to 36kA. Both ranges have current ratings available up to 125A and rated voltages of up to 690v.

The S800S range bridges the gap between standard MCBs that typically have 10-15kA breaking capacity and maximum currents of 63A, and physically larger moulded case circuit breakers (MCCBs) typically used in industrial applications. Aimed at OEMs and the industrial sector, the S800S series can be used to provide protection in industrial environments. They increase the amount of space available in switchboards and other enclosures by offering the same levels of performance to MCCBs but in reduced physical dimensions.

The S800S range is ideal for traction applications onboard rolling stock and trackside, marine installations, plus industrial environments such as petrochemical and steel plants. Tripping curves available are B, C, D plus K and Universal Current versions offering 250v DC ratings per pole.

The S800N series has been developed for commercial building applications such as shopping centres, airports, hospitals and office blocks. Tripping curves available are B, C and D.

Both the S800S and S800N ranges are available in 1,2, 3 or 4-pole versions. All versions are designed to be fitted onto standard DIN rail and are complemented with a full range of customer fitted accessories such as auxiliary contacts, shunt trips, under voltage trips, rotary drive mechanisms and RCD blocks up to 63A rating.

Both the S800S series and S800N series MCBs are available through ABB's distribution network.

Smart metering provides sensible solution to reducing energy bills

The need for businesses and consumers to become more energy efficient and cut energy bills is making smart energy meters an increasingly attractive solution for managing energy use. Alan Roadway, Product Manager for ABB, explains what's possible with smart meters and outlines some of the benefits they can bring for domestic, commercial and industrial users.

Spiralling energy prices and government imposed initiatives and targets for improving energy efficiency are making both consumers and businesses ever more aware of the amount of energy they are using.

Part L of the UK Government's Building Regulations Act encourages accurate measurement of energy consumption. For businesses and industrial end users in particular, the challenge to date has been to identify the most appropriate way to fulfil this obligation.

The consensus of opinion is that smart meters are increasingly providing the answer. These meters provide users with the technology to gain an immediate and accurate picture of their energy use which can be usefully employed to encourage a change energy consumption behaviour.

Greater functionality

The underlying rationale behind Part L is that if users are made responsible for monitoring their energy consumption, they will take more action to reduce their usage and employ more energy efficient practices. To date, however, it has not been easy for either consumers or businesses to do this. If the home or building owner wants to get a better idea of their next bill, some complicated maths and knowledge of multiple tariff rates is required.

Energy bills for most buildings are either the result of a meter reading by the supplier, or more commonly, are based on an estimated reading made as the result of the meter reader being unable to gain access to the meter. According to Energywatch, at least 7 million domestic customers receive estimated bills, which can result in inaccurate charges to the customer and affect the ability of energy suppliers to maximise their revenue collection.

Smart metering technology offers a solution. Smart meters, such as ABB's DELTAsingle electricity meter, are able to show the kWh consumption figure on an LCD screen.

For users, the benefits include being able to monitor consumption levels at different times on a regular basis, helping to identify trends. This particularly benefits SMEs, as they are able to get a more accurate idea of their energy consumption before their bills arrive, and be able to take steps to try to minimise future energy usage.

Another key benefit of smart meters is that there is no need for them to be physically visited by a meter reader. Depending on the meter's capabilities, data can be collected remotely, using bluetooth, a pulsed output or wi-fi connectivity. This would be particularly beneficial when collecting domestic meter data, as homeowners are often not at home to provide access.

Employing energy tariffs

More sophisticated smart meters can also be connected to the Internet, making it possible to include tariff control functionality. This could potentially enable consumers to switch between tariff rates according to normal or peak periods or to switch between tariffs offered by different suppliers. For businesses in particular, this provides the ability to better manage energy costs by being able to monitor the effect of existing practices at different times of the day.

Furthermore, by connecting smart meters to an Ethernet, business users are able to monitor spending at different office locations, enabling them to identify areas of excess consumption, and encourage best practice schemes across different sites.

Increasing adoption of smart meters

According to Energywatch, the estimated cost of conducting a wholesale installation of smart energy meters into just domestic properties in the UK is approximately £86m. This is on top of the £800million a year already spent on replacing, installing, maintaining and reading existing meters. Energywatch is encouraging the installation of smart meters as part of suppliers' existing replacement programmes, growing the base of installed meters gradually. However, debate continues as to who should bear the cost of installing smart meters into homes and other buildings and facilities around the UK.

Utilities argue that it would be difficult for them to recoup the costs of installing the meters due to the de-regulated nature of the UK utilities industry, where consumers can move easily between suppliers. This makes it harder for suppliers to pass on the cost of installation to homeowners who can switch to a competitor after having a smart meter installed.

In Europe, the adoption of smart meters is greater as competition is less intense and government measures and intervention have helped encourage installations.

However, it can be argued that having smart meters installed into consumers' homes may actually increase trust between consumers and their energy supplier, as they would be able to better understand the information displayed by their meter and thus have a more accurate picture of their costs. It is anticipated that consumers would save up to £35 per year due to changes in consumption behaviour as a result of using smart meters, and consumption would be reduced by between 3% and 15%. For utilities, there is also the prospect of maximising their revenue collection through being able to more accurately bill customers based on actual, rather than estimated, energy consumption.

For businesses, the case for installing smart meters is based around cost versus benefits. The benefits, in terms of reduced energy costs, appear to outweigh any short-term costs involved in installation. Smart meters will enable businesses to invest in technology that will help reduce consumption in the long-term, by providing accurate measurements of energy use, enabling businesses to act upon the instant information supplied.

Commercial building owners can also benefit, as they will be able to get separate readings for different occupants, and monitor their consumption levels accordingly.

Summary

ABB offers a range of energy metering equipment and can provide expert advice on which meter will be the most suitable for your facility. ABB can also provide support to ensure that businesses get the most out of the meter's capabilities to help with cutting their energy consumption levels.

Plan for safety

The reliability of switchboards and associated switchgear can be directly attributed to an effective service plan. Shutdowns due to breakdowns are expensive, disruptive and in most cases unnecessary. Dave Powell, Service Manager for ABB's low voltage business, explains the steps that responsible operators should take to ensure the safety of their switchboard equipment throughout its operational life.

To ensure that switchgear provides the best electrical protection, it is imperative to ensure that switchboards and their associated equipment are maintained and tested regularly. Maintenance and testing should be done for two reasons; firstly to comply with regulations, and secondly as a preventative maintenance measure to help avoid unplanned shutdowns. Despite this, many operators of electrical distribution equipment are failing to check their equipment on a regular basis, increasing the possibility of failure and compromising safety.

Penalties for not heeding safety

The Electricity at Work Regulations (EaWR) were introduced in 1989, to reduce accidents and raise awareness of safety in the workplace. Whilst the regulations are old, the recent introduction of the Part P household regulations have served to encourage renewed discussion on electrical safety in the workplace.

The main stipulation of the EaWR regulations is that equipment must remain safe throughout its operational life. This means that all equipment should be checked and maintained to ensure it is working at an optimum level of safety and efficiency while in service. This is especially important in relation to switchboards, where circuit breakers are relied upon to provide safety to workers, reduce downtime and minimise the effect of an electrical overload on the rest of the building.

Failure to comply with EaWR can result in up to £5,000 in fines for a single breach and the financial penalty can be unlimited should a case be transferred to Crown Court. Should a case occur as a result of a lack of electrical protection, ignorance of the regulations cannot be used as a defence, so it is vital that operators ensure that regular electrical maintenance checks are carried out.

But how is this achieved, and what constitutes an 'appropriate' level of electrical maintenance? The frequency of maintenance and service checks depends largely on the environmental conditions that the switchboard is exposed to. If it is located in areas subject to dust, condensation or pollutants, then it will need a service more often than a switchboard not exposed to such conditions.

Even if a switchboard has not been used frequently, it does not mean that it should be expected to work. "We have only switched this breaker once in the last seven years now it will not reclose", is indicative of the expectation that some customers have on switchgear. Poorly maintained circuit breakers may not trip when required or may not be able to be reset after tripping, either of which will render the switchboard unsafe.

If the protection device fails to open on a fault the resulting damage and disruption to business can be severe, especially with main MV and LV switchboards, where major repairs could take days or even weeks.

Many 415V switchboards now have automatic mains-to-generator change-over systems, requiring breakers to open and close remotely. However, if the breakers are not maintained, the reliability of this system reduces with time. There is little point in having standby generators if the change-over system fails through lack of maintenance.

Setting the maintenance plan

Several key factors need to be considered when determining a maintenance and testing plan. These include assessing whether the switchboard and switchgear is still suitable for the ambient conditions, and examining the state of the switch room. The initial assessment will also consider if the equipment can handle short circuit currents and overloads and an assessment of the age and condition of the switchgear, including previous maintenance and failure history. All of these factors have an influence on the extent and frequency of the maintenance plan proposed.

Where Air Circuit Breakers (ACBs) are used, manufacturers will also issue maintenance instructions, which can be used as a starting point for deciding on maintenance schedules. In instances where circuit breakers are damaged in any way they should be isolated and taken offline immediately, to prevent harm to anyone coming in contact with the unit.

For example

A five-year service plan incorporating three planned maintenance visits will typically allow operators to plan future replacements that have been identified during routine maintenance. Examination and adjustment of arcing contacts will continue to protect main contacts from severe wear and allow for planned replacement. A thorough visit will examine and test both switchboards and the switchgear itself to ensure that all parts are working satisfactorily. While five years would be suitable for the switchboard itself, manufacturers may have different recommended periods of inspection for individual equipment such as circuit breakers. For example, ABB would typically recommend inspection on its ACBs which ranges from every six months to two years, depending on the environmental conditions the equipment is located in and the type of operation –i.e. distribution or process.

ABB and some other manufacturers that build switchboards and their components also provide maintenance services. These manufacturers are ideally suited to providing electrical maintenance services as their knowledge of the equipment used is extensive.

During an inspection, the inspector will examine the switchboard, based on the factors outlined earlier. An experienced site inspector, irrespective of their origin, will test not only the protection device itself but also the mechanical aspects of the protection provided.

Having performed maintenance and testing of switchboard, the inspector will issue a report with test certificates and advise on the recommended future maintenance and test periods. The recommendations should ensure that switchboards are kept in optimal conditions.

Summary – inspect to protect

Electrical maintenance is crucial in ensuring safe and efficient operation and minimising the risk of unplanned shutdowns. To ensure that a switchboard will perform when it is required the most, then regular servicing and testing is a must.

Compact softstarter range launched by ABB

ABB has expanded its softstarter range with the launch of a compact version for small to medium sized motors. Designed for motor currents from 3 to 45A, and motor voltages of up to 600V, the PSR compact softstarter complements ABB's existing PSS and PST ranges for applications from 3A to 1050A.

Available through ABB's Strategic Industrial Partner network, as well as existing softstarter alliance partners, the PSR provides a compact device for OEMs and panelbuilders serving the food and beverage, process and automation and water treatment industries.

The PSR softstarter is available in three physical sizes and nine current ratings, with widths ranging from 45mm to 54mm, making it suitable for installation in confined spaces. To help simplify installation, the PSR can be either screw-fitted or mounted onto DIN rails.

Ideal for pump, fan, mixer and conveyor applications, the PSR Softstarter range is designed to minimise starting currents and reduce the risk of current spikes in small to medium-sized motors. This helps to minimise the impact of motor starting on the electrical network and also prolongs the life of mechanical components.

As well as standard indicator lights showing operational status, PSR softstarters also offer several indicator and control possibilities. Three potentiometers located on the front of the PSR, provide users with control over motor starting and stopping. Two of the potentiometers can each be set to control motor ramp up and ramp down times. This is particularly helpful for pump applications, where the gradual slow-down of the motor is required to prevent 'hammering'. A third potentiometer enables the user to set the initial voltage of the PSR softstarter required to start a motor.

Two types of signal relays are also supplied with the PSR softstarter. All three frame sizes have a run relay, which indicates that the PSR is running. In addition, the two larger-sized PSRs have a Top of Ramp (ToR) relay. The ToR indicates when a top speed has been reached so that the load can be switched on, useful for applications such as compressors where a motor needs to be up to speed before the load is applied. The PSR also benefits from having built in bypass contacts, which leads to reduced power losses whilst the motor is running at speed, and reduced heat build up.

The PSR range can manage ten starts per hour. If greater starting capacities are required, an auxiliary cooling fan is available, enabling starting capacity to be increased to 20 starts per hour.

The PSRs can also be controlled remotely with the addition of ABB's fieldbus plug, which enables simple and fast connection to any existing protocol in the FieldBusPlug range through an optional 'neutral' fieldbus-independent interface.

ABB provides turnkey robotic solution in £650k Lander Automotive project

ABB has supplied five robotic cells to Birmingham-based Lander Automotive Ltd, a leading supplier of welded tubular structures to the automotive industry. The robots, which form the core of a project worth around £650,000, are the first of their kind to use the latest ABB control equipment and software.

The cells include a mixture of new and refurbished robots, which are designed to produce metal seat frames for eventual installation into cars built for a major Japanese car company. The cells, together with other processes, including CNC tube manipulators, presses, riveters and assembly, form a best practice, lean, flexible manpower line some 25 metres long. This line takes raw materials through to the finished product.

The project included programming the robots, electrical and software design, installation and commissioning. The most novel aspect of the project was the software engineering. This is the first time that a programmable logic controller (PLC) from ABB's new AC500 range has been used in a robotics project, and the programming software had to be specially tailored for the automotive sector.

In common with many of the world's leading automotive-sector manufacturers, Lander standardises on a programming approach known as EDDI (Error Diagnostically Driven Interface) to control all of its robots. ABB engineers were able to modify the standard approach and use an EDDI within ABB's new AC500 PLC and CP500 HMI . The controller's Codesys programming tool saved considerable development and commissioning time by enabling the ABB engineers to use previously tried and tested software blocks.

ABB delivered everything on an extremely tight, 15-week schedule from order placement, in spite of the development work. Furthermore, any future ABB projects in the automotive sector should be even quicker and easier, since the newly developed software modules can now be re-used whenever necessary. All the code complies with IEC 61131-3 and relies on tried and tested robotic and control interfaces.

Mid-range HMI. Functions include: Localised control, Diagnostics, Alarm handling, Sequence control, Manual and auto control

Providing a turnkey solution means that ABB has the expertise to train Lander personnel in every aspect of the new cells. This overall capability also means that ABB is an effective one-stop-shop for any support that Lander needs in the future.

In addition to the AC500 controller, ABB supplied a Profibus communication module to enable the new cells to communicate with Lander's wider control system. Other ABB equipment supplied included I/O cards, operator interfaces (HMI's), power supplies, miniature circuit breakers, isolators, safety relays and mini relays.

A surge in electronics requires effective protection

With more sophisticated electronic devices in the home and in commercial and industrial environments, the need to protect equipment from lightning surges, and from electrical surges caused by man-made devices, has become much more acute. Ian Parmenter, ABB's Product Manager for Surge Protection Devices, explains how Surge Protection Devices (SPDs) can provide protection from surges, and reduce the cost of replacing damaged equipment.

The average UK home has become a treasure trove of digitally-controlled electronic goods, including DVD players, DAB radios and LCD televisions. In addition, electrical devices that we take for granted, such as washing machines, refrigerators and dishwashers, have become more advanced, using motors that constantly stop and start.

This is even more so in the workplace, where we rely on electronic equipment such as computers, while the factory floor is dominated by automated machines carrying out a complex set of actions often transmitted by a centralised control system.

In all these environments, we're at a loss should any of these devices break down as a result of a power surge. At work, equipment that is damaged as a result of a surge can cost thousands in lost productivity, not to mention the cost of repair. Many devices, either in the workplace or in the home, can be expensive to fix or replace so ensuring that appropriate SPDs are installed is essential.

Surges can be caused in three main ways:

1. Lightning strikes - A direct lightning strike can cause blackout and even the risk of fire to a building. Buildings that have a lightning protection device, such as a lightning rod, to dissipate the power of a strike, can still be indirectly affected. The power absorbed by the protection device can be transferred to the main power supply near or in a building and send a surge to electrical equipment. Underground cables situated near a lightning strike can also transmit the effect of the strike to electrical equipment inside a building.

2. Overvoltages - overvoltages can be caused by equipment inside a building, and occur due to current surges - i.e. where a current would exceed its maximum permitted operating level. Short-term overvoltages are also known as transients. Their effect on equipment varies; from crashing PCs, to wearing out a computer's internal components. They can be caused by anything that effects a sudden change in power usage. Common examples include office photocopiers or microwaves, which are both capable of creating surges that are then sent through a building's electrical system.

3. Man-made items outside a building - overvoltages can also be caused by surges being transmitted from a distribution or sub-distribution board into a building via telephone lines or data cables.

What can SPDs do?

SPDs divert a current surge harmlessly to the ground. They also limit overvoltages to values compatible with the withstand voltage of the equipment or devices connected - i.e. the upper-limit of the amount of voltage a device uses during operation.

Whilst most houses can typically have standard SPDs installed, office buildings and factories would benefit from an audit before installing suitable surge protection. Ideally, such an audit should consider the following:

1. Environmental parameters: should take into account the frequency of lightning strikes in the area, as well as the radius a lightning strike will cover.

2. Installation and equipment parameters: should consider what type(s) of equipment are already in place - e.g. lightning rods, and also the location of the distribution board and the equipment to be protected.

3. Security parameters: need to assess the potential implications of loss of equipment and/or life, as well as environmental risks.

Such factors can all affect the level of SPD protection required for a building. Those that require the highest level, such as high-rise commercial towers or large automated factories, would benefit from the full protection offered.

Zoned approach

It is rare that one SPD can provide protection against all types of current surges to a building, so different layers of protection are required. A zoned approach is generally considered to be the best way to maximise protection, by ensuring that all areas of a building are protected against both external and internal surges. At least two zones of protection are required for many commercial buildings.

The following illustrates the different zone levels to consider, to ensure effective protection:

Zone 1 - the first zone would protect against direct lightning strikes, and would typically be placed outside of a building.

Zone 2 - would be found inside a building on the main distribution board. This would typically protect against the external surge caused by a lightning strike, and provides a second layer to deal with residual external surges. It is also the first layer of protection from external overvoltages caused by power lines or cables.

Zone 3 - would be used to protect against internal surges, and provide protection to equipment such as PCs, microwaves and photocopiers. This third layer should be placed near to the location of any critical equipment. In a work environment it will often be on a sub-distribution board.

Zone 4 - additional protection can be added to the location of the end-user equipment. In the home, this would typically be provided by extension leads with SPDs included. Sockets with SPDs are also now available.

How can ABB help?

ABB's low voltage products feature inbuilt protection against different types of current surges. Type 1 SPDs can manage a current capacity of up to 15kA, and are able to handle a direct lightning strike. They can be supported by Type 2 SPDs, which can handle network voltages from 57V up to 600V. Using Type 2 protectors will serve two purposes, providing both the back-up required to support the Type 1 SPD, and protection against internal surges on distribution boards throughout the facility.

There is also a need in modern offices to protect equipment used for data and telecoms storage and transmission. Such is the reliance of many companies on electronic data, it is vital that companies use SPDs to protect against potential data loss or unavailability. Dedicated SPDs, like ABB's OVR TC SPD, will protect equipment connected either to telephone lines, computer links or looped systems for voltages of 6V, 12V, 24V, 48V or 200V.

The cost of replacing equipment being damaged by either internal or external surges far outweighs the cost of providing adequate protection for a building. In particular, breakdowns caused by surges can result in thousands being lost in business. Providing effective protection against current surges is essential to ensure a smooth-running business and a safe and secure home.

ABB launches single phase compact Electricity Meter

ABB has released a new electronic electricity meter called the DELTAsingle, aimed at the commercial and industrial market. At only 72mm in width, it can be installed in even the most confined locations.

The DELTAsingle is designed to measure power consumption of sub-circuits of up to 80A, and can be placed on sub-distribution boards.

The DELTAsingle has a number of interactive functions that enable it to be read in three different ways. The front of the meter has a 6mm high LCD display which shows 6 digits, so that readings are easy to record locally. The DELTAsingle can also emit a pulse output, which can be fed into a building management system. Power consumption can then be monitored by minute, hour, day or whatever is required. The meter readings can also be performed via an infra-red interface for serial communication, so that it can be read with a serial communications adapter over M-bus, RS232, TCP/IP, or LON.PL networks.

Should a power failure in a building occur, the meter is equipped with a 'Super Cap' power back-up facility that will run for 48 hours. A red LED at the front will flash to indicate how much of the battery's power has been consumed.

The DELTAsingle meter takes only seconds to install, with its DIN rail design and plug-and-play connections.

The DELTAsingle has been developed according to IEC standards 620520-11, 62053-21 and 620054-21, ensuring the highest quality measurement of electricity consumption.

ABB's manual change-over switch ensures constant power

ABB Limited has expanded its range of OT switches with the OT change-over switch. Enabling quick change-over to back-up electrical supplies in the event of a power failure, the switch is ideal for applications demanding a constant supply of power including Gen Set, banks, and utility operations.

Based on the OT switch range, the OT change-over switch is available in both component and enclosed versions from 160A up to 800A, and fully-rated up to 690v. In the event of a primary electrical circuit failure, the switch can be disconnected from the primary circuit and connected to the emergency back-up system, ensuring minimal disruption to power supply in the event of a power surge.

Manually operated, the OT change-over switch range features an advanced compact design which is up to 35% smaller than its OETL predecessor, enabling the unit to be installed into confined spaces. The OT change-over switch also increases flexibility as it can be fitted in any position, including upside-down, if required with no de-rating enclosed or open air.

The two-way switch is enclosed in one unit, saving time on installation; where conventional units with single switches would have to be installed separately.

As with the standard OT and OS range, the OT change-over switch has been manufactured in accordance with the highest manufacturing standards. It is fully thermal-rated for both enclosures and in open areas without the need to adapt the unit. It has been built according to KEMA, UL and IEC 60947-3AC-23 and IEC 60947-3AC-33 specifications. The handle is IP65 protected, providing protection from live parts, and also prevents dust and water entering the switch mechanism.

The change-over switch range has a mechanically based design, with metal parts and double brake switching as standard. These features help to prolong operational life, compared to units from other manufacturers that typically use plastic and ceramic parts. It also increases safety by providing double isolation from live parts.

The change-over switch also has a patented operator independent quick-make / quick-break mechanism, providing better responsiveness and reliability when in use.

OT switches are supported by a common range of accessories including handles, shafts, auxiliary contact blocks, bridging bars, terminal shrouds, locking accessories and terminal clamp sets.

New ABB terminal technology eliminates wiring mistakes on MCBs

ABB has launched a range of miniature circuit breakers (MCBs) aimed at OEMs, panelbuilders and the industrial sector. The System pro M compact® incorporates a number of new features designed to eliminate wiring connection errors.

A key feature is the positioning of the cabling terminal in front of the busbar connection terminal, making both terminals easier to access and see. By placing both terminal ports at the bottom of the MCB, connections can be made secure by using only one screw to fasten both the busbar connection and the electrical cabling into their respective terminals.

ABB has also introduced auxiliary contacts for the pro M compact® range, which can be added to the bottom of an MCB instead of the side. Saving up to 50% space in enclosures, this feature increases the number of auxiliary contacts which can be installed, expanding the number of remote monitoring options. Plug-in connectivity also makes the contacts simple to connect.

The pro M compact® MCBs also offer a reduced height compared to ABB's previous range, saving around 2cm of space per MCB. This provides additional installation space for when space is at a premium.

ABB's patented release system enables easy removal without the need for a screwdriver. Release connectors on the back of the devices allow them to be simply disconnected from the busbar after turning power off and disconnecting the wiring.

The pro M compact® range is suitable for use worldwide as the materials used to manufacture them exceed standards for both European regulations for RoHs and UL, the US directive for electrical components. The pro M compact® MCBs can be ordered ready for installation for both Europe and the US. A Europe-only version is also available.

ABB helps the desert bloom

Electrical equipment produced by ABB Low Voltage Products is helping turn parts of the Sahara Desert green, transforming it from a wasteland into a productive agricultural area.

ABB is supplying MCBs, ACBs and softstarters to a project that is taking water from the Nile and pumping it to an irrigation system to provide water to small farmers, growing maize and other crops.

The electrical components form a vital part of 12 power stations produced for the project by Westac Power. During the planning stage, ABB supplied its own experts to Westac to help it define the technical aspects of the project, in particular the sizing and selection of the motor starters.

The eventual solution involved building a number of generator sets, each with a diesel engine, an alternator, a motor control centre and a motor. These drive pumps are submerged in the river. The new power stations involve a total of 34 generator sets ranging in size from 650 kVA to 1850kVA. Some of the power stations have up to four generator sets, allowing different combinations of pumping power to be operated, depending on demand, and allows some of the sets to be shut down for scheduled maintenance. ABB's MCBs and ACBs were sized to suit these different possible combinations.

Managing Director of Westac, Tony Shirtliff, says: "The benefits of the ABB softstarters are that they prevent stress on the generators.

"When the motor stops, a column of water supported by the pump collapses, turning the pump in the reverse direction and hence the motor itself. This generates a back EMF, a voltage acting in the reverse direction that can produce currents which can damage the generator. This obviously leads to interruption of water supply. The slow starting and stopping allows us complete control over the motor and pump, rather than the pump taking control."

This system of electrically-driven pumps has benefits over the previous method, which involved diesel engines driving mechanical pumps, mounted on barges in the river. As the demand for water grew as the project irrigated more land, more barges were needed and their operation became cumbersome and inconvenient. It was difficult to maintain electrical connections to the barges due to significant changes in the Nile's water levels.

A significant part of Westac's contract was training, an aspect that ABB played a full part in, providing a day's training to six of the customer's onsite electrical engineers. They were trained in how to set up the motor starters and how long they would take to start and stop the motors.

Shirtliff says: "We have standardised on ABB products for four years. ABB has a worldwide reputation and by using them, we give the customer the confidence that he is getting what he needs. The customer wants to know that the equipment we use is first rate and that he will get the back up he needs. We get that with ABB."

New ABB multifunction High Speed Counting module for PLC offers enhanced control of rotating machinery applications

ABB's new DC-541 multifunction module for its AC500 PLC offers a flexible device enabling operators of high-speed rotating machinery to optimise efficiency.

Capable of measuring machinery speeds of up to 50kHz, the DC-541 can be used as an interrupt module and a high speed counting module for 24V signals. Incorporating digital inputs and outputs in a single device, the DC-541 features eight channels which can be configured to operate as either inputs or outputs and individual or combined counting functionality.

For interrupt applications, the module's eight channels can be configured as either interrupt inputs or PWM pulse train outputs or a combination of the two. It can be configured to monitor up to eight pieces of rotating machinery, depending on the application.

For instance, if the module detects that machinery is running at the wrong speed, it can signal the AC500 which can then use the module's digital outputs to transmit a high-speed signal to correct the speed of the machinery to its new setting. This same function can also be used to regulate machinery at slower speeds too, particularly useful applications include automated picking and packing applications, where accurate control of speeds is essential.

In high speed counting mode, the DC-541 module can be used for high frequency counting jobs up to 50kHz. Again, the device's eight channels can be configured to measure rotational speed, time and frequencies of 50kHz, 5kHz or 2.5kHz either separately or as a combination.

To optimise accuracy, the module can automatically calculate whether to measure the time elapsed between two pulses or to count the pulses per time unit. With resolutions of 50, 100 or 200 microseconds, the DC-541's interrupt function provides plant operators with precise data which can be used to optimise rotating machinery efficiency.

The DC-541 module's 'plug and play' technology enables it to be added to an AC500 already in operation. It can be readily configured using the AC500's Control Builder (CoDeSys standard) programming software, with users just needing to integrate either the 'interrupt' or 'high speed counter' component into their application program. Instructions for the module can be added to any programs already installed.

United Utilities adopt UMC22-FBP motor controllers to manage wastewater Treatment Works

Improved control delivered by ABB's UMC22-FBP intelligent motor controllers is helping United Utilities to gain better management of its energy needs at its wastewater treatment works at Croston in North Merseyside.

The installation is part of a move by United Utilities to install intelligent control systems at all future installations, providing them with better control over their energy requirements, and also better monitoring of any faults.

The Croston treatment facility supports a population equivalent of around 26,000 people, treating wastewater from domestic and trade discharges.

The site was suffering from hydraulic overload and a number of areas needed upgrading, including the installation of a new grit removal plant. To control the plant new LV switchgear and motor control centres were required, as well as modifications to some of the motor control centres already in place.

In all, around 19 controllers are being installed at the site. By installing UMC22 controllers, United Utilities will be able to monitor and control each motor through a central PLC system, using PROFIBUS fieldbus communications, a standard widely used in the water industry for instrumentation. As well as providing sophisticated electrical overload protection for the pumps and other rotating machinery, the UMC22s will permit diagnostics and remote control over the internet.

By standardising on the UMC22, a number of benefits can be realised, including a simpler design and construction of the control panel, smaller space requirements and less internal wiring. This will also help to standardise and rationalise the types of components required, reducing equipment costs. Capital Expenditure (CAPEX) savings are estimated to be in the region of 5-15% of the total electrical and instrumentation construction cost.

By utilising the UMC22, United Utilities expects that considerable savings will be made in operational expenditure (OPEX) costs.

The UMC22s will highlight the performance and reliability of the motorised equipment at the facility. Diagnostic information will include energy consumed by each motor, so that United Utilities can better manage their energy usage. The controllers will also be set up to operate under back-up control should any communication systems fail on any of the site's PLCs.

By using intelligent control systems such as the UMC22, monitoring and control can be made possible over the internet. Being able to access such detailed diagnostic information remotely will also have the long-term benefit of increasing the efficiency and security of the Croston site.

Balancing act: damage vs. disruption

Properly designed discrimination and back-up protection minimises the disruption and cost of guarding against electrical faults. Janet Roadway, product manager for power circuit breakers in the UK with ABB, argues that only those designers with real training and experience can achieve the right balance.

Protecting people and property is paramount in the event of a short circuit or overload. It's vital that a fault in the microwave of a hospital kitchen triggers a circuit breaker to cut the supply to the faulty oven to prevent a fire, for example. On the other hand, no one wants to disrupt the entire hospital with an electrical blackout each time a light bulb blows.

Striking a balance between maintaining maximum protection for the minimum disruption is far from straightforward and best left to specialists. It has been observed that some electrical consultants are now attempting to pass this responsibility on to panel manufacturers or site contractors, who often lack the training and experience to tackle the job.

As a leading manufacturer of circuit breakers, ABB is increasingly being approached to carry out discrimination studies. Naturally, any responsible manufacturer will be able to provide discrimination tables and other relevant data on their equipment. However, factoring in protection against electrical faults is really a strategic job that should be carried out by whoever is designing the electrical system as a whole.

The first step in the process is a fault protection study, which asks, "what will happen if things go wrong?" Its first priority is to ensure full protection for people and property. Its secondary aim is to minimise disruption and provide continuity of service.

A system for distributing electricity throughout an office block or hospital typically has an inverted tree structure. At the top is the main switchboard, fed by a HV/LV transformer and protected by a large air circuit breaker (ACB). This feeds several out-going moulded-case circuit breakers (MCCBs).

Each of these then feeds a number of smaller distribution panels, which may be protected by more MCCBs, miniature circuit breakers (MCBs), or fuses, depending on the current they have to deal with in normal operation and the fault currents they may encounter. Eventually the electricity reaches the equipment that provides the load on the system, such as the microwave in our example.

Selective action through discrimination

Discrimination aims to ensure that only the protection device immediately upstream of a fault will trip, leaving the rest of the supply intact. If all the protection devices in a supply chain are set to blow instantly at the same threshold current, they may all trip at once if there is a short circuit. By equipping different points in the supply chain with protection devices that have adjustable tripping characteristics, the designer can provide the discrimination needed to minimise the disruption caused by a fault.

There are three basic approaches to discrimination. The first is to use devices set to trip at higher threshold currents further up the supply chain. The second is to place a time delay on circuit breakers at a higher level in the chain. By the time a fault current would cause them to trip, a circuit breaker lower down the chain should already have isolated the fault and things should be back to normal. The third approach is to discriminate on the basis of the total energy passing through the circuit breaker. This is related to the square of the current and time. This third approach is the best way to achieve a system that is optimised for both current rating and physical dimensions.

It all sounds fairly straightforward, but the relationship between different devices is complicated by the potential for interaction between them.

Interactive protection

As well as the designed-in tripping mechanism that responds to the size and duration of the fault current, a high fault current can generate magnetic repulsion between the contacts inside a circuit breaker. This effectively loosens the contact between the surfaces, increasing impedance and reducing the current flowing through the device. This in turn will limit the current flowing to the next device in the supply chain.

This is not something that will show up on the charts of time vs current that are used to define and predict the way each protection device behaves.

Very fast acting devices may also limit the current. This is because they act before the current has time to reach its peak.

Manufacturers therefore provide discrimination tables to give reliable predictions of how a particular combination of devices will behave in practice. These show that the level of discrimination actually available is often higher than the isolated behaviour of individual devices suggests.

In the end, however, total discrimination may not be feasible. The level of fault current that would need to flow or the time for which it would be allowed to run may simply cause too much stress and long-term damage to the distribution system. Achieving a balance between the potential damage and the disruption caused by a fault is ultimately a judgement call that is best made by experienced electrical consultants.

Optimising cost and protection

The other balancing act that the electrical consultant on any large project must try to pull off is maximising the level of fault protection while minimising the cost and space devoted to protection devices. It's not just about initial equipment costs: Office buildings charge by the square metre, for example, so an oversized switch room will cost the owner a lot of money over the life of a building.

The regulations governing low-voltage distribution enable designers to get round this using back-up protection. Back-up protection exploits the current-limiting effect of upstream circuit breakers to enable the installation of downstream devices that have a smaller rated breaking capacity than they apparently need. This is because the fault current the downstream breaker "sees" is restrained by the upstream device. Instead, only the upstream device needs to have a breaking capacity to match the highest possible fault current.

It's obviously vital to get back-up protection right. If a circuit breaker experiences a higher fault current than it's rated for, it could be damaged or even explode.

The mechanisms behind backup protection are extremely complex. Added to this is the fact that data is almost always unavailable to the end-user, having been obtained from experiments carried out in specialist power laboratories. This effectively ties the designer to a single manufacturer who can guarantee that back-up protection matches the level required.

The other drawback of back-up protection is that it effectively rules out the possibility of total discrimination. There is a threshold fault current called the takeover current, above which both the circuit breakers will trip. Total discrimination is only possible for fault currents below this level.

Even this brief discussion shows that there is more to designing an optimal fault protection system than just looking at the characteristics of individual protection products. Only by appreciating the potential for interaction between devices can a designer balance all the conflicting needs of safety, continuity of supply, space and cost.

It takes an experienced practitioner to juggle all these requirements and come up with the optimum solution for electrical fault protection. So it's always worth calling in specialist help, rather than relying on a general site contractor. The right designer will protect the installation from damage, minimise disruption and save the client money in the long run.

Building a smarter home

Consumer electronics are coming into their element with the automation and control of entire household appliances. The so called ‘Smart Home' - for so long just the preserve of the super rich - looks set to change the way ordinary homes are built.

Imagine arriving home one evening after work. There is no-one at home but the lights come on when you walk in, the curtains are drawn, and by the time you have washed, changed and set the table, your evening meal is ready and cooked to perfection. Next morning, you wake at 7:30am to the sound of one of your favourite CDs playing in the background and the lights in your bedroom switched on. The brightness increases gradually, mimicking natural daylight and letting you wake up in your own time. Downstairs, the intruder alarm system switches off and the coffee machine switches on to make a drink. The curtains open; the towel heater in the bathroom warms the towels, all while you lie in bed preparing for the day ahead.

The concept of the intelligent, or Smart Home, where automated systems take care of many of the routine tasks of every day life, has long been a staple of science fiction, but developments in networks and computerisation mean that the dream is fast becoming a reality. These days, newer houses are increasingly built with low voltage communication network cables for a wide range of Smart Home systems.

Services and equipment that currently utilise these networks in much of everyday life include security, home theatre and entertainment, telephones, door-phones and intercoms, PC and Internet networks and surveillance cameras. Manufacturers with experience in the automation and control of commercial and industrial buildings are starting to look at the residential market and are aiming to bring the benefits of automation to the private householder.

Dream into practice

Several building developments in the UK show what can be achieved by bringing networked control systems into the home.

The Intelligent House, built by Laing Homes in Battersea, South London, features remote control access via a mobile phone, to sophisticated mood lighting and zoned heating systems. For added security, a seven-day lighting sequence is recorded and replayed when the owners are away. The house also has cinematic surround sound, multimedia systems, computer links and a water leakage detector.

One of the house builders featured on Channel 4's Grand Designs television programme has created a futuristic home environment using intelligent electrical equipment. Tom Perry's Cloud 8 house uses ABB's i-bus intelligent installation system to control everything from windows that automatically open or shut depending on the room temperature, through to lights that flash when the phone rings.

With ABB's i-bus system, individual electrical circuits are operated by separate switches or sensors and without complicated wiring or two-way circuits. Commands are relayed via a single two-wire control cable from a sensor or a control panel and received by actuators which execute the command, such as switching on a light automatically if it gets dark outside.

"The beauty of the i-bus system is that it's done on two wires", explains ABB's i-bus product manager Gareth Rowlands. "Whereas anything else we talk about is a number of looped wires, this is a pure two-wire system. The reduction in cabling brings savings in installation time and energy costs, and makes adding to a system extremely easy. The system lends itself to either residential or commercial applications."

Living in the future

As more intelligent buildings appear on the market, the more the market seems to demand them. A recent report by the Consumer Association revealed that 45% of people surveyed were interested in having the sort of functions a Smart Home could offer, while 40% of respondents could see themselves living in a Smart Home in 10 years' time. Unsurprisingly, those most interested in living in a Smart Home tended to be younger, family households already with some form of pay-TV and home entertainment system. Also people on higher incomes who tend to welcome technology were interested in living in these ‘homes of the future'.

Safety and security features emerged as the most popular aspect of living in a Smart Home with 70% of respondents valuing the safety and security features they could offer. The benefits of remote access also had wide appeal.

Building a market

According to Gareth Rowlands of ABB, the Smart Home concept still only appeals to a relatively niche market, although the market will grow: "The householder with £5millionto spend on a house will see the added cost of a home automation system as trivial, whereas a person spending £100,000 on a house will see it as prohibitive.

"Yet, we need to look to the future and realise that buyers of new houses are increasingly able to choose the fittings they want. It's all about customer choice and developers could offer the Smart Home concept as another option that would give them an edge over their competitors."

Although there are currently very few Smart Homes in the UK, there has been a small increase in the building and conversion of properties with integrated Smart Homes technology. Another market route for the technology is through 'expert home improvers' and 'DIYers', where comfort and convenience are not the only drivers but also the likely addition to the resale value of the property.

The greatest opportunity for growth in the use of Smart Home technology looks set to come from the area of consumer electronics, particularly home entertainment and personal communication systems. Initial demand will no doubt come from the more technology-literate, early-adopter households.

In terms of building a market and persuading more people to take automation in their homes, the best systems will be those with a high degree of flexibility and are easy to install. Solutions like those from ABB, which can be used to build a small system such as a lighting control system, allowing other controllers and facilities to be ‘bolted on' later, will be instrumental in getting consumers used to living in a Smart Home and eager to see what more it can do for them.

Type testing - ensure you're covered

In spite of the fact that type testing is a legal requirement for switchboards within the EU, there is still some confusion over what is required. Janet Roadway of ABB clarifies the legal position and offers some practical advice.

Type testing is a legal requirement for low voltage assemblies sold throughout the European Union. Without it, switchboards, control panels and other assemblies up to 1000V AC or 1500V DC will not earn the coveted CE mark, which shows that all the relevant European directives have been met.

In spite of this, it's common to find some confusion about what is actually required, especially when it comes to partially type tested assemblies. Some people are under the impression that partial type testing means that some of the elements in an assembly need not be type tested. They're wrong, and equipment supplied on that basis should not be legally traded.

Meeting standards

Type testing aims to ensure that low-voltage assemblies comply with two key European directives: the Low Voltage Directive and the Electromagnetic Compatibility Directive. The directives deal more with overall aims and intentions than with the details, so if you're looking for step-by-step instructions showing how to comply with them, the most important standard for UK suppliers is BS EN60439-1.

BS EN60439-1 defines a type tested assembly (TTA) as: "A low-voltage switch gear and controlgear assembly conforming to an established type of system without deviations likely to significantly influence the performance from the typical assembly verified to be in accordance with this standard."

In other words, the supplier must prove by a comprehensive programme of testing that their basic designs comply with the standard and that any alterations from the tested designs won't significantly affect the performance in terms of safety or electromagnetic interference.

A partially type tested assembly (PTTA), on the other hand, is: "A low-voltage switch gear and controlgear assembly containing both type-tested and non-type-tested arrangements, provided that the latter are derived (e.g. by calculation) from type-tested arrangements which have complied with the relevant tests."

So the assembly may be different from the tested assembly but it must be based on it. For example, the component layout may have changed, but the calculations and design criteria have been proved in a TTA. In other words, opting for a PTTA doesn't mean opting for an easier testing regime: The predicted performance of every part of the assembly still needs to be derived from a fully type tested sample.

All change

When specifying an assembly, it is important to understand the types of change that might significantly affect a TTA's performance and therefore its compliance with the standard. A supplier may not be able to tailor the equipment to your application if the required changes jeopardise its CE mark.

Significant changes include:

• Major structural changes to the assembly carcass. These will affect the air flow and temperature rises within the assembly.
• Reductions in busbar cross-sections or changes in busbar profiles and spacings will affect the amount of current they can carry. The smaller the cross-section of the busbar, the higher its temperature will rise from passing a giving current.
• Changes in the type or quantity of busbar supports or support structures. If a short circuit does occur, the electomagnetic forces within the assembly may try and force the busbars out of shape. Inadequate support could allow them to come away and potentially contact other components and cause a short circuit.
• Exclusion of or changes to major short-circuit protective devices taken account of in the programme of type tests.
• Reductions in compartment sizes. Like other structural changes to the carcass, smaller compartments will result in higher temperature rises that those taken account of in the type tests.

Performance requirements

The standard lays down a comprehensive package of performance requirements, which must all be met, regardless of whether the assembly is to sold as a TTA or PTTA. Any decent supplier should have the documentary evidence and detailed test data to back up any compliance certificates and customers should make sure they ask to see it.

Comprehensive temperature testing results must be available for bus bar systems and functional units. Beware of test results that do not combine bus bar tests and functional unit tests, or which are conducted with unpainted steelwork. Any type of coating will affect a material's ability to radiate heat, so tests on unpainted surfaces will not give a valid temperature rise profile.

The dielectric properties of all the insulation must be tested and recorded.

When it comes to the ability to withstand short circuits, all tests must be certified by an independent authority such as ASTA (the Association of Short-Circuit Testing Authorities) or a member of LOVAG (the Low Voltage Agreement Group). Ensure that the test records are comprehensive and that the units supplied are in accordance with the test records.

The effectiveness of the protective circuits is obviously of grave importance for the safety of equipment and personnel. Tests should look at the effective connection between the exposed conductive parts of the assembly and the protective circuit. Continuity and ratings records should be available for all earthing circuits and connections. Like the main circuits, protective circuits also need to be tested for their ability to withstand short circuits. Ensure that the main earth bar has been independently tested and certified to the appropriate fault ratings.

Clearances and creepage distances must be recorded and complied with. All mechanical components must be tested for their compliance with the standard and the supplier should again be able to supply detailed records.

An independent testing organisation will also need to carry out IP tests to check the degree of protection that the assembly enjoys.

Type testing is an expensive business, costing in the region of £30k or £40k for each assembly. One way in which switchboard manufacturers can save money is to enlist the help of component manufacturers. Some manufacturers will supply components for type testing free of charge and may even help towards the testing costs for an assembly. In the case of major suppliers such as ABB, there could even be the scope to use some in-house type testing facilities where appropriate. It pays to shop around and find out what help is available. However expensive the tests are, assembly manufacturers certainly can't afford not to perform them.