Lightning can cause significant damage to sensitive, mission-critical systems within a building if lightning protection measures are not adequate. Paul Considine of Wieland Electric explains how the risk can be aligned to the cost of protection

With the increasing use of, and dependence on, technology in just about every business, protecting sensitive equipment is becoming ever more important. In a manufacturing or logistic operation, for example, disruption to processing or handling systems can have a catastrophic effect on productivity. Similarly, in the financial sector, server rooms are mission-critical and any failure can lead to losses of millions of pounds every hour.

Poor power quality is responsible for many different electrical problems. In addition to the obvious accidental causes like power cables being damaged by digging work, or bird strikes on overhead lines, every load on the electrical grid will have some impact on the power that is delivered. Some power quality problems are very complex, but there are also many common causes says John Outram, managing director of Outram Research

A purely resistive load, for example an oven, will tend to pull down the local voltage due to the current flowing in the power lines that have a finite impedance; capacitive and inductive loads can cause the current to lead or lag the voltage, degrading the power factor; motors and pumps have large inrush currents, potentially superimposing transients onto the voltage; and modern compact fluorescent lighting may only draw current at the peak of the voltage waveform, causing harmonic distortion of the supply voltage.

In most cases the impact of loads on the power supply is not problematic, but in extreme cases the effect on other devices on the grid may be serious. The mechanisms by which the utility companies try to accommodate all of these influences may themselves add transients and momentary variations, further complicating the situation. The effect of poor power quality can range from unnecessarily lost power in transmission lines caused by low power factor (out-of-phase current and voltage), to flickering lights, and power wasted in motors and transformers due to the presence of harmonics.

Taking motors as an example, when power is wasted it will generally be dissipated as heat, increasing wear and shortening life. Harmonics may also cause vibrations in motors which can increase noise as well as be a potential source of mechanical failure.

Some causes of power quality problems are almost impossible to control; vulnerability to accidental causes such as those mentioned above is a function of our infrastructure and they should be expected occasionally. However, with the right equipment and approach, power quality issues can be identified and resolved, and although complex situations may require experienced power quality professionals, engineers can identify straightforward issues by following six simple steps.

Step 1 - Gather Information
If you don't measure it, you can't manage it! However, before any measurement survey is made, think about the best approach. How is the problem presenting itself? Are complaints widespread? Are there any common threads? What about the infrastructure or the installation itself? Is it old; is there any corrosion, leaking oil? If so, could the distribution impedance have been compromised?

Most problems are local or self-inflicted. One of the best sources of information is the operator of equipment affected. Asking the operator when the problem happens, whether other things go on at that time and what he/she thinks is causing it, can provide excellent clues to the cause of the problem.

This stage should also be used to prepare for the survey. What are the local loads? How many points need to be monitored? The more information available, the better the monitoring can be targeted.

Step 2 - Produce a Harmonic Profile
Harmonics on the line tend to lead to long-term problems - motors and transformers overheating or other failures that do not happen instantaneously, although they can also cause rapid equipment failure. Typically these measurements would be taken over a period of at least a week, as most power quality issues have either daily or weekly periodicity (for example, happening the same time every day, or happening during the week but not at weekends). Understanding the periodicity can give important clues as to the cause of the problem; for example a car breaker's yard is unlikely to be causing problems that happen during the night!

Harmonics are evaluated continuously and averaged over a period of time. Measuring the harmonics does not require as high a sample rate as transients because the lower harmonics will tend to contain the most energy. Of particular interest in 3 phase systems are the 3rd, 6th and 9th harmonics, as these will not generate balanced current flow but reinforce each other, and therefore can cause high currents to flow in the neutral.
The harmonic direction - the phase angle of the current with respect to the voltage waveform of the harmonics, can also be a helpful clue to the cause of the problem. In this case however, it is important to make sure the analyser records harmonic direction correctly from typical data, rather than inferring it from a non-typical waveform capture, which may only be captured due to a momentary transient, notch, or ring.

Step 3 - Look for transients
Short-term transients such as spikes, dips and sags can cause immediate failures - for example blown light bulbs, PLCs resetting or computers dropping internet connections and worse, when they lead to partial process failures, where part of a production line is affected causing back-up, overflow, perhaps spillage and general loss of control. They can also be responsible for less catastrophic though highly irritating problems such as flickering of light bulbs.

Although some transients can be slow, others can be very fast. Monitoring such sub-cycle transients requires high-speed waveform capture, and power quality analysers such as the Outram Research PM7000, offer sampling speeds in excess of 1MSPS.

However, with high sampling rates it is not possible to record all the data, and so some way needs to be found of identifying the waveforms to be retained. Most power quality meters offer a threshold approach, which may mean an iterative process of setting different thresholds until the right amount of data is captured. The best systems offer a data management technology, which retains the ‘worst' waveforms over whatever is the monitoring period chosen. This avoids the need to set thresholds, simplifies setup, and significantly improves the likelihood of capturing useful data first time.

Step 4 - Compare the current and the voltage
Having monitored transients and harmonics, the engineer will have a good idea of what the problem is electrically, but may still have no idea of the cause. By monitoring the current and voltage together with good time resolution the cause of the problem can often be identified quickly. If the current and voltage rise or fall together, the problem is likely to be outside of the system being monitored, whereas if they move in opposite directions, the problem is likely to be inside.

Consider monitoring the supply at the point of entering a building - if the current spikes up and the voltage spikes downward at the same time, it will probably be because a load within the building has drawn more current, pulling down the voltage due to impedance in the transmission lines, whereas if they both move together, the fall in voltage is likely to be caused by an external load, and the local current falls in sympathy. The situation is not always simple because some modern electronic equipment, particularly those using switch-mode power supplies, can display negative resistance. Investigating the cause of a positive or negative link between current or voltage movement should add to the understanding. 
Many power quality analysers offer a fixed interval for current and voltage measurements, an approach that might cause critical information to be lost. Figure 1 shows how variable sampling intervals - in this case Outram's adaptive store technology - can identify rapid changes whilst still making effective use of the analyser's memory.

Step 5 - Undertake some detective work
At this stage we should know whether the problem is within our building or not. If we are causing the problem, then all that is required is a step by step approach to identify the culprit. This can be done by moving the power quality analyser on to monitor different loads within the building or simply by turning things off while monitoring until the cause is identified.  Sometimes problems can be revealed by their physical effects; hot spots on connections or excessive humming of transformers are typical examples.

If the problem is external, a little more detective work is required and you may need to involve the Utility Company. Some frequent causes include pumping stations, compressors, car breakers yards and welding shops, although causes can range from fixed installations or steelworks and other heavy industry to mobile equipment such as cranes.

If the source of the problem is still not obvious, then it is useful to measure the power quality at the substation to isolate the cause. Sometimes the premises next door to the cause may suffer serious power quality issues, but the impedance in the line will mean that nothing is visible at the substation.

Most power quality issues will require the engineer to repeat these steps in an iterative process - for example repeating the steps at different points in the electrical supply network to try to identify the cause geographically.

Step 6 - Confirm the diagnosis
Once the engineer has identified what he/she thinks is the cause of the problem, it is useful to see if there is any other corroborating evidence or even any contra-indications - particularly if the remedial action is likely to be expensive or unpopular!
Usually measurements will also be taken after the problem has been resolved to ensure that no lingering effects exist.

Quality of power is becoming an increasingly important issue. Utilities are penalising companies for poor power factor as the power wasted can be considerable and costly to the Power Company. Modern loads, such as electronic power supplies and compact fluorescent lights, are more and more introducing significant harmonic distortion that not only causes power to be wasted, but can ultimately shorten the life of motors, transformers and other valuable equipment.

By following a systematic step-by-step process and using the right equipment, an engineer can troubleshoot his plant for simple power quality problems. Complex issues may require more specialised expertise using instruments capable of distinguishing and recording unpredictable events, enabling unexpected or previously unencountered power quality issues to be identified.

The consequences of poor power quality include increased electricity consumption and equipment and process failure. With the ever-increasing focus on efficient operations, reducing energy costs and cutting carbon dioxide emissions, power quality issues must not be ignored.

The long awaited launch of the new low voltage switchgear and controlgear assemblies standard, happened in January of this year. Unusually for such an important document, it was issued as a technical revision, meaning it immediately supersedes the 60439 version. Craig Mckee of 3 Phase Design looks at some of the training needs created by the new standard's arrival

This new standard is a significant change from the previous one, one of the most surprising changes for some will be the removal of the terms ‘type tested assembly' and ‘partially type tested assembly', these have been replaced by ‘design verification'. With the well known seven type tests increasing to 13 design verification characteristics

A further change is that Part 1 is now ‘general rules' with Part 2 now also required to be used for all power switchgear and controlgear assemblies. Part 6 (which is yet to be published) is to cover busbar trunking as previously covered by Part 2 of the IEC60439 series.

Design Verification;
The 13 design verification characteristics are split down into two main areas, that of ‘construction' and ‘performance'. The construction tests cover such areas as:
-?Strength of materials and parts - which looks at the suitability of plastics and metals to prove the long term capabilities of the equipment.
-?Degree of protection of enclosures - referencing the same standard as before. 
- Incorporation of switching devices and components - this requires the panel builder to ensure that devices are installed in line with manufacturer's instructions.
- Terminals for external conductors -?again putting the onus onto the panel builder to ensure that the contractor will be able to terminate his cables onto the switchboard.
The performance areas cover, among others;
- Temperature Rise -?one of the biggest areas of change in the standard revolves around this area. No longer can you fit a device into a compartment and rate it at a level it would not be capable of carrying without exceeding the limits set by the standard. The standard now requires that the maximum current a circuit is capable of carrying, within the temperature limitations, is noted as its rating, irrespective of what the device manufacturers claims for the device alone.
-?Short circuit withstand strength - this is principally the same set of tests as per the previous version of the standard, with a few amendments.
-?Mechanical operation - this ensures the components of the system are mounted in such a way that through normal use, they will not fail or change the capabilities of the switchboard. In this case the test value is set at 200 operations.

After successfully completing all 13 design verification characteristics, the benchmark will be set for future adaptations of the design, since IEC61439 now accepts both verification by design rules and verification with a reference design, when carried out in line with the standard, are equal and equivalent to verification by test. This is another area of change that can be misinterpreted and needs full clarification by reading and understanding what options are open to users for each clause of design verification, since not all are acceptable under each clause.

Upon completion of the above, and moving into production, the standard requires routine verification be carried out by the switchboard manufacturer to ensure continued compliance to the design verified solution is met. These routine verifications must be carried out on each and every board that is manufactured and is principally a simplified subset of the 13 design verification characteristics, but this cannot be seen just as a job for the final QC department, since important areas such a device ratings, terminal sizes, swapping of components etc. needs to be fully investigated prior to any work being started.

The above has concentrated on the panel builder. However consultants must also be aware of the changes that IEC61439 will bring, with some being slightly more subtle than other, but nevertheless important to what can be supplied. An excellent example of this is the slightly flawed thought we currently hold of a Form 4 assembly. Currently, most people would expect this to mean a multi compartmentalised assembly with each device being housed in its own ‘zone'. IEC60439 did not give a clear account of what an acceptable segregation method was. However clarifications within IEC61439 now confirm the outer case of a device ie an MCCB is acceptable to create a Form 4 assembly, without any further segregation. If the end user and consultants require a multi compartment assembly, their specifications will need to be updated to take account of this, or they could end up with a switchboard being supplied in line with the standard, but not what they actually wanted.

With these changes, the daunting thought of reading through the IEC61439 standard with no one to give guidance, and the inevitable costs in this current economic climate, it is easy to think it will be pushed into the sidelines or lie at the bottom of the ‘to-do' list until it is too late.  Using a good quality training provider with in-depth experience in the subject matter is essential to gain the most efficient use of both time and money. With this in mind, 3 Phase design has created a training programme that explains the standard in a relevant and interesting waymaking it easier to understand -?with the added benefit of being able to give completely independent advice on any area within IEC61439, including specification checking and switchboard testing support.

In a dangerous situation, emergency alarm systems (fire alarm systems or burglar alarm systems) should signal ‘actively', and remain ‘passive' in safe situations according to DEHN UK. Malfunctions of these systems (no response in case of danger, or alarm signal in case of no danger) are undesirable and expensive. False alarms sent by emergency alarm systems result in expenses, which, in the industrial countries, amount to several hundred million Euros per year. Another aspect of malfunctions is the possible direct or indirect danger to human lives. In this context, we may remember the malfunction of the fire alarm system in the tower of the Frankfurt Rhein-Main airport in 1992, where a false activation of the fire extinguishing system occurred because of a lightning strike. Within a few minutes, the air traffic controllers had to leave the control room. In this critical situation, approaching airplanes had to be redirected to other airports. Considerable delays occurred in the air traffic. False alarms of emergency alarm systems are also disturbing in another respect:
- When false alarms accumulate, the operator can no longer rely on the system and questions the significance of the system (investment) as such.
- The guard starts ignoring alarm messages.
- Neighbours will be disturbed by acoustic alarms.
- Fire-fighting forces (e. g. fire brigade) will be bound unnecessarily.
- The activation of the fire extinguishing system causes interruptions of operations.
- Damage is caused by not signaling existing dangers.

All these factors cause unnecessary expenses. They can be avoided, when possible causes for false alarms are already recognised in the design stage and are eliminated by suitable preventive measures. For this purpose, the German Insurance Association (Gesamtverband der Deutschen Versicherungswirtschaft e. V. - GDV) published VdS guidelines (VdS 2095; VdS 2311; VdS 2833). One of the measures also requested in the VdS guidelines is lightning and surge protection.

A coordinated lightning and surge protection prevents a false alarm caused by atmospheric discharges and improves the availability of the early detection of dangers and alarms. When installing comparable alarm transmission systems, for which, out of financial reasons, a VdS approval is not used (in residential building for example), the guidelines may also be used for project design and for the construction as well as for agreeing individual measures between constructors and operators. Indeed,  fire alarm systems installed nowadays have an increased surge immunity in accordance with IEC 61000-4-5 for primary and secondary wires as well as for the mains inputs. However, a comprehensive protection against damage by lightning discharge and surges can only be achieved by external and internal lightning protection measures.

Monitoring principles
Different monitoring principles are applied for emergency alarm systems:

Impulse line technology
The information from the triggering alarm device is transferred in digital form. This allows recognition of the alarm device and the exact localisation of the trouble spot (Fig. 9.9.1).

DC line technology
Each alarm line is permanently monitored according to the closedcircuit principle. If an alarm device is activated in the line, this line is interrupted and an alarm is triggered in the control and indication equipment. Hereby, however, only the alarm line can be identified but not the individual detector.

Regardless of the used monitoring principle, the lines of the emergency alarm system must be integrated into the lightning and surge protection of the complete system.

Protection recommendations
For protection of alarm lines with dc line technology, Blitzductor CT BCT MOD BE. is recommended. It is chosen according to the voltage of the alarm lines, which is normally 12 or 24 V. Blitzductor CT BCT MOD BE is recommended to avoid having to change the loop resistance of the alarm lines too much.

Regardless of the line topology, the outputs of the control and indication equipment, for acoustic and visual signalisation for example, should be protected by Blitzductor CT. Care should be taken to ensure the nominal current of the protective devices is not exceeded. In case of nominal currents > 1A, the company suggests a DEHNrail DR 24 FML protective device be used. (see Table 9.9.1). The control and indication unit is normally connected to an exchange line of a fixed-network operator by means of a telephone dial unit. For this application, the SPD type Blitzductor CT, BCT MOD BP 110 would be suitable. The surge protection of the power supply is important, too. For alarm systems, which are certified by the German Insurance Association, (systems recognised by VdS), the manufacturer of the alarm system should be contacted. The installations as well as the lightning and surge protection equipment have to be set up in accordance with VdS 2095, VdS 2311 or VdS 2833.

A distinct increase in the operational reliability of these systems can be reached with specific lightning and surge protection of alarm systems, including the prevention of false alarms when no danger exists, and the prevention of costs arising from this. This allows effective damage limitation by informing the auxiliary personnel reliably., counteracting potentially catastrophic conditions including danger to human lives and pollution of the environment.
In the event of injuries to persons or environmental damage, the operator of a plant is liable first. This comprehensive responsibility for security can normally be expected from managers or executives of a company. However, in the legal sense, an operator of a plant is a technical layman, who is not able to assess the potential risk involved in a technical solution. Therefore, skilled persons as suppliers of technical solutions must ensure in each individual case, the solutions offered correspond to the actual requirements.

Regardless of the fact, whether fire alarm systems are VdS-approved systems or not, they should be furnished with a surge protection.

The introduction of the new and more complex standard BS EN 62305:2006 Protection against Lightning has led to many new questions and the resurfacing of several ‘old chestnuts'. We look at a few of the most frequently asked questions fielded by Furse engineers

My building has stood for 100 years, and has never been hit.  So there is no chance of it being struck now!

Not being hit by lightning in the past has no bearing on being struck in the future. The probability of a strike and whether protection should be fitted will be shown by carrying out a risk assessment. York Minster was around 600 years old when it was ‘eventually' struck by lightning in 1984, causing extensive irreplaceable damage. Remember a direct strike to the structure is not even necessary for lightning to cause damage through fire, electric shock or electronic systems failure.

I have an air finial on the tallest part of the building and a down conductor, so that should be adequate?

This is unlikely to give adequate protection in accordance with BS EN 62305 which calls for a full Faraday Cage, comprising a number of conductors on and around the building.

My building has reinforced concrete columns. Can I use these columns as down conductors?

Yes, provided you ensure the electrical continuity of one or more reinforcing bars in each column. Where sections of reinforcing bar overlap, they should be welded or clamped together, or overlapped by at least 20 times their diameter and securely bound for the entire length of the overlap.

How do I know if my building needs lightning protection and, if so, what level of lightning protection system (LPS) is required?

There's no intuitive way of doing this - you need to carry out a risk assessment in accordance with BS EN 62305:2006 Part 2. The risk assessment in BS EN 62305-2 is much more detailed and has many more parameters than the assessment contained in BS 6651. There are software packages available that can help. Furse's bespoke risk assessment software package is called StrikeRisk. It has just been updated to version 5, and a free trial version is available to download from its website - www.furse.com

I have looked at the number of parameters required to carry out a risk assessment, but cannot find all the information. What should I do?

The risk assessment carries default values, which can be used where accurate information is not available. However, these values are conservative, so you should try and obtain as much accurate information as possible.

Why is there now so much emphasis on protection of sensitive electronic systems? This wasn't a requirement of BS 6651.

The protection of electronic systems was covered in Appendix C of BS 6651, and although this was an informative annex, the philosophy is broadly similar to that of the new standard. Our increasing reliance on electronic systems means that damage or downtime can have serious financial and operational consequences and hence their protection is reflected in the single risk assessment of the new standard..

I have a lightning conductor system on my building, so will this protect my electronics within the building?

No, this will protect the structure itself but not the electronics within it. You therefore need specialist surge protection to prevent equipment damage from LEMP (lightning electro-magnetic impulse). BS EN 62305 focuses on coordinated SPDs (surge protection devices), where the locations and LEMP handling attributes of a series of SPDs are coordinated to nullify the conducted LEMP effects - thereby protecting equipment within their environment.

Is it adequate to put surge protection on the main electrical incomer only?

Although protection of the main incomer is certainly recommended, other services should be considered for protection against transient overvoltages (surges). For example, a lightning strike up to 1km from a building can transfer huge voltages onto overhead or underground cables - like data or telephone lines - through inductive or resistive coupling. Once transferred to the cable, transients will flow along it, seeking a path to earth and damaging any electronic components they encounter.

I am fitting an LPS to a building, which contains no sensitive electronics systems. Do I still need to fit Type 1 (equipotential bonding) SPDs?

Yes. Type 1 SPDs (for mains power supplies) and Category D SPDs (for data/telecom lines) form an integral part of the equipotential bonding requirements for an LPS. They are needed to prevent partial lightning currents from causing dangerous sparking and the possibility of a fire or electric shock hazards. Type 1 SPDs are not designed to protect equipment, but form the first part of a coordinated SPD set further consisting of Type 2 and 3 SPDs.

For more than three decades, the design and testing of switchgear and controlgear  assemblies has been governed by IEC 60439-1. In 1999, the IEC started a thorough overhaul and full restructuring of this series of standards within the SC17D/MT11 committee. In January this year, parts 1 and 2 of IEC 61439 were published. certification body Kema looks at the new standards' progress

Kema's project manager for industrial components, Henk Kormelink, explains: "The first thing to note is, although the new IEC standards already apply in many parts of the world, they are still awaiting European ratification. Furthermore, in the current transitional period, the choice whether to apply the old or new versions rests with switchgear customers. Eventually, of course, the new standard will prevail".

Kema is thoroughly familiar with the requirements of the new standard. Kormelink is a member of the IEC SC 17D MT11 committee, which is responsible for restructuring the IEC 60439 series. In this way the company contributes to the improvement of the standard by bringing in its experience as a test and certification body and its familiarity with the operations of equipment manufacturers. In fact, he is one of the few representatives of test and certification bodies on the committee and is thoroughly familiar with the requirements of switchgear manufacturers.

The old standard, IEC 60439-1 (Low-voltage switchgear and controlgear assemblies - Part 1: Type-tested (TTA) and partially type-tested (PTTA) assemblies), covered the design and testing of a wide range of equipment. This standard put the emphasis on testing of TTA assemblies, which led to difficulties when revising designs or substituting components. How should a PTTA assembly be verified? This resulted in a situation in which many PTTA systems in the market did not fully comply with the standard. The old situation made it particularly difficult to apply the standard to variants of type-tested assemblies. To prove compliance with the old standard for partially type-tested assemblies was difficult, or at least not very clear.

The new standard provides clear rules for dealing with design variants and component substitutions and can therefore provide end-users with greater certainty that their equipment meets the requirements. Kema is working with a number of large customers to recertify existing products to the new standard and to adopt it in new projects.

Wider scope
The new IEC 61439 standard has a different structure, in that Part 1 includes the general requirements, while Parts 2 - 6 address specific types of equipment. Now this structure is aligned with the IEC 60947 series of standards. Under the new standard, the TTA and PTTA definitions have been removed and now tests can be combined with calculations or design rules to demonstrate that equipment meets the requirements. This is the most important change in the new standard. As a result, the standard now specifies how some changes can be made to equipment without requiring new type tests. This can clearly save a great deal of time and money and is particularly relevant to modular switchgear. More assemblies now meet the requirements and the old partially type-tested assemblies in particular are now covered much more effectively.
The two new standards published so far are:
- IEC 61439-1, General rules (Part 1)
- IEC 61439-2, Power switchgear and controlgear assemblies (Part 2).
The following parts will be published in 2010 to 2011: 
- IEC 61439-3, Distribution boards 
- IEC 61439-4, Assemblies for construction sites 
- IEC 61439-5, Assemblies for power distribution 
- IEC 61439-6, Busbar trunking systems

Until these other parts have been published, the older standard, IEC 60439 will remain in force for the design of such assemblies.

Moving from the old to the new standard
Manufacturers should consider how best to implement the new standards in their design and test workflow. In consultation with the test and certification body they use, it may be possible to re-use test data obtained for the old standard for verification of designs under the new standard. This will reduce the costs of introducing the new standard.

However, this is more difficult with respect to the temperature rise requirements where re-using old data can lead to lower product ratings. To solve this issue, it may be advantageous to carry out some temperature rise tests in accordance with the new standard. This is an aspect panel builders will need to carefully address and discuss with their test and certification bodies.

The standard is detailed and complex, so getting advice from experts in the field is recommended. In recent months Kema has discussed the consequences of the new standard with our large customers and helped them get started with this process.

Testing reference systems
Under the new regime there is much greater scope for testing a reference system and then using calculations and design rules to prove that systems derived from this reference design also meet the requirements.

Working with a reference system as a basis for other designs is particularly attractive when dealing with many variants of the same systems as it can save significant time and costs. The new standard ensures that the performance of all assemblies can now be more thoroughly verified than before. This can be done by testing, by calculation/measurement or by satisfying design rules. Verification covers parameters such as the circuit rating, impulse rating, short-circuit rating, diversity and temperature rise

Special requirements in the Middle East
The speed with which the new standards are adopted will to some extent depend on the demand from the market. In Kema's experience, customers in the Middle East are already requesting that their products be certified to the new standard. The company is particularly familiar with this market and its requirements. In fact, they can carry out tests at non-standard temperatures such as 50°C, which is a requirement of some customers in this region.

Comprehensive service
Kema's positioning is that it can cover the whole range from low voltage to high voltage testing and has extensive in-house test facilities. Any low-voltage tests that are carried out in external laboratories are always witnessed by one of its experts. Depending on the desired degree of risk reduction manufacturers require, they can choose appropriate measures that correspond to an acceptable safety level. This approach can be applied from a simple IP test right up to comprehensive panel certification schemes such as Kema-Keur for panels and the Kema World Panel Program. All these factors combined put the company in a strong position to offer a comprehensive service to manufacturers planning to adopt IEC 61439.

Your move
Panel builders must address the issue as to when their customers want to see the new standards applied. They will then have to review their design, test and manufacturing processes and identify the changes that need to be made. Any additional testing will have to be designed, together with the test and certification body.

Furthermore, panel builders will need to update their design process to incorporate the new arrangements for verification based on the new calculations and design rules, and decide how to optimise their business processes to benefit from the new options. Clearly, any type testing should support this new approach effectively. In this way panel builders can continue to offer their customers the best product at the most attractive price, supplied in the shortest possible time.

A big step forward
In essence the publication of the IEC 61439 series is a great step forward, as the standards now fit in better with the demands of both manufacturers and their customers. The new approach means that compliance with the requirements of the standard can be verified more easily for a range of equipment, without requiring excessive testing or leading to inflexibility. Implementing the standards effectively will, of course, require extensive consultation between a manufacturer and its customers, and with the test house and certification body used by the manufacturer.

Click on the PDF below for a breakdown of the Kema Risk Reduction Building

Aceri are pleased to announce their scheduled webinars for AutoCAD Electrical 2010 software.

That increasing numbers of people are concerned with energy conservation and management is  unquestionable. However, in real terms there remains a very long way to go before the reduction targets set by Government can be realised. Now, a British designed and manufactured product is set to develop the market for cost-effective energy metering as Martin Russell of Tyco Electronics' Energy Division explains

Tyco Electronics Crompton Instruments has designed and manufactured an energy meter that is flexible and can be used in a broad variety of applications. That the product competes aggressively with imported goods, yet delivers superb quality combined with simple installation and programming is a remarkable testimony to a novel design and manufacturing process within the UK project team.

Many of us do not recognise that UK engineering remains held in high regard globally for its quality, reliability and innovation. Designed and manufactured in the UK, the new Integra Ci3 instrument certainly upholds this from both standpoints. Reliability is assured thanks to the use of surface mount electronics, robust microprocessors, the sourcing of high quality components and inherently rugged mechanical design.

What this means for end users is significant. While energy management and particularly energy saving are high on Government agendas, the evidence suggests that progress towards better energy control remains slow in industry and commerce. There are many reasons for this, the primary ones being lack of real knowledge about energy management; high price for initial installations; risk of system reliability (there are more things to go wrong); lack of capital incentive (despite the many examples of cost savings in energy consumption).

On the premise that one cannot manage what one cannot measure, the vital first step in any energy control is to know what is being used, where it is used and when. Only metering can provide the tangible answers, yet aside from large, sophisticated building management systems (BMS), the uptake of metering technology has been slower than would be desirable if Government is to meet its ambitious energy consumption and greenhouse gas emission reduction targets.

Hence, the availability of suitably sophisticated, reliable, yet cost-effective meters is a major catalyst to removing financial risk from new management systems and at the same time provide data that's essential to effecting effective energy controls.

A further factor has been that most energy meters have been relatively complicated. Switchgear specialists and panel builders demand simple, flexible products that are easy to install, don't break down, require minimal stocking and deliver added value to their end users. They also refuse to add significant cost to their products because they perceive that in doing so they diminish their own competitiveness - a vital consideration in today's economic climate.

The need has been for a product that provides an inexpensive way to measure the broadest possible range of parameters, while being easy to program and quick to install. Crompton Instruments design team within Tyco Electronics set out to create a near universal meter that complemented its existing range of products, yet satisfied as many of the market's requirements as possible. The challenge was to do so at the lowest possible price, highest possible quality, with exemplary reliability and full functionality.

Other facets of the market include the wide variety of potential specifiers and users of energy meters. Once the domain only of building management systems specialists, now products are used by electrical installers, energy managers, facilities managers, panel builders, switchgear manufacturers and installers, electricity generators and Distribution Network Operators and even end users themselves. The need for a

universal approach coupled with absolute simplicity is apparent. Coupled with this, where once product was generally supplied either direct from manufacturers or via specialist distributors, now mainstream electrical wholesalers increasingly look to stock at least some energy metering products. The need for a minimal stock, spares and options inventory is therefore another consideration.

Innovation by design
The design of the product started with the involvement the voice of customers and internal sales, design, product management, procurement and manufacturing teams. Apart from resulting in a holistic process to ensure design efficiency, this early consultation influenced the manufacturing methods deployed, improved and truncated the design phase and ensured a high quality, reliable product from the first production runs.

At the heart of the instrument is a completely new homogenous single board that houses all the electronics for the meter. Having just a single board processor overcomes spares and production stocking issues; potential for unreliability; and the risk of incompatibility between boards at future dates. The single board approach also ensures cost control.

The boards are fabricated using surface mount technology that is not only suited to low cost high volume production, but also results in very high reliability both in manufacturing and in the field.

Only high quality standard value components are used - the risks and costs associated with bespoke or semi-bespoke devices is eliminated, as is the need to carry discrete spares.

The central processors have been rationalised to give a common development platform for future extensions to the Crompton Instruments range of products.  Even the development tools (software) are common. What this gives is almost limitless scalability and a high degree of ‘future proofing' as both the Crompton Instruments' product range and end user's systems develop or grow.

Comprehensive specification
The new Ci3 meter is the first of a new generation of digital metering systems that complements the existing Crompton Instruments Integra range. All the main electrical and power quality parameters can be measured from any supplies. Twenty fundamental measurements are offered, including single and three-phase, total harmonic distortion (THD), currents, frequency, KWh, and so forth.

The Integra Ci3 is programmable to suit single-, three-phase three wire and three-phase four wire systems, while scalable current transformer ratios enable the display of any current range.

The backlit LCD display simply clicks into place during manufacturing and screens are selected by the end user using four simple buttons and an intuitive interface. Two plug in output ports allows a combination of various output modules - for example, pulsed relay and/or Modbus - to be incorporated.

The installation of the Ci3 is simplicity itself. The DIN 96 enclosure has integral retention clips to enable fast, safe and secure panel mounting in various material thicknesses without any external screws of clips. The meter gives true RMS measurement and is fully CE certificated. An IP65 protective cover is available for harsh environments.

The British energy management market is expanding, but this new inexpensive and reliable British development is set to accelerate that expansion.

For more information visit www.integraCi3.com or call 0870 870 7500

Sub and final distribution plays a crucial role in the measurement and control of  energy. It is time for distribution boards to evolve argues Steve Dyson, product manager for Hager

The whole nature of a commercial electrical installation has changed over the last few years. Just three or four years ago sub metering and the use of control devices or a building management system was a rarity. Not now.

In the face of growing concern about the environment the government has legislated. Whether or not you agree with this approach, it means that the electrical distribution system has evolved. It is now time for distribution boards to meet these changing needs.

The most important change came with the changes in Building Regulations in 2006. Part L2 of the Building Regulations for non-domestic buildings states that appropriate metering is included at the design stage so that building operators can monitor where the energy is consumed. It states that the meters and sub meters must account for 90% of the estimated consumption in a building.

Property owners and tenants must have accurate information about their energy usage. An overall figure does not meet this requirement; the information must show the different areas of consumption. They must be able to say for example how much of the fuel is used for lighting, power, air conditioning and so on. These regulations apply to all new premises with floor areas of 500m2 or greater.

An ideal solution is sub metering for each type of load. You should also note that the regulations state that separate metering is required for final distribution boards totalling 50kW or more. Most Type B boards exceed this figure when fully loaded.

Guidance on establishing a metering strategy can be found from CIBSE. The leaflet "TM39:  2006 Building energy metering" is an updated version of the General Information Leaflet "GIL65: Metering energy use in non-domestic buildings".  The latter can be downloaded free of charge from the internet.

So assuming that the easiest place to provide sub metering is at the distribution board, the installer generally needs to consider using a meter box and whether it offers enough space for fitting any CTs that are used with the meters - sometimes these are placed in separate cableways.

Such solutions add cost, need extra space and take time to install. The meter box should also complement the distribution board since sub distribution boards are often visible, so aesthetics are important. The whole solution can smack a bit of being an afterthought if you are not careful.

Most manufacturers will have a suite of products, which will help overcome such problems and it is possible to have custom built boards that incorporate metering. Produced as a special the latter may be an expensive option. I would argue that because sub metering is now such an integral part of most installations, a standard Type B distribution board should now allow metering to be fitted within it.

Using our new range of Type B distribution boards to illustrate the point, there is enough room next to the incomer to install metering. The metering pack is supplied wired with the appropriate CTs.

At this point it is worth reflecting on why sub metering is installed - it provides information so that businesses can reduce their energy usage. Regular main meter readings will provide some information about the overall energy consumption, but it reveals little about where energy problems might lie. Installing sub metering will help identify which end use or service is performing well or badly.

This will enable the operator to take targeted action and then measure the result of that action. Ultimately it should help businesses reduce their energy use and costs. Such thinking also helps to establish where to install sub metering. While we need to achieve the 90%?energy monitoring target, we want to achieve this cost effectively.

You may expect certain services to consume large amounts of energy, for instance lighting in an office can account for 40% of energy consumption. Certain areas or rooms in a building may also consume large amounts of energy - for instance a computer room in a school. Such judgements help to form the foundations of a metering strategy.

At this point it is worth referring to the Cibse leaflet TM39. It states metering end-use energy helps:
- establish the breakdown of energy use within a building i.e. where does it all go?
- provide a better perspective on building operation
- identify where energy use is greatest
- identify what the minor loads are
- promote a detailed assessment of demand patterns and benchmarking to identify end-uses that are untypically high
- allow patterns of energy use to be monitored
- reveal useful trends between, say, day/night, summer/winter, weekday/weekend
- provide one year moving averages cumulative sum plots comparing actual consumption with targets
- spot things going wrong before it is too late
- operators to understand and manage their buildings better, resulting in greater energy savings
- provide feedback to: building designers; building operators; manufacturers; government and supply side industry on performance achieved, helping them improve performance by setting better targets
- gain BREEAM credits
- designers complete the building log book
- demonstrate compliance with building regulations.

Of course installing the metering is only part of the story. To be effective the data must be both collected and then acted upon. Sadly it is only too common to see an energy management strategy fail because of this.

Now it is no longer good enough to simply just have metering. Since the end of last year it is a condition of selling or leasing commercial property that an energy performance certificate is provided - which means data is vital.

Buildings with poor energy ratings will suffer, as will those that cannot demonstrate good energy performance - whether this is because there is no sub metering or because the data has not been collected.

To aid collecting the data, meters should have a pulsed output offering remote measurement of kWh or for linking into an energy management system.

Having measured how and where the energy is being used, the next step is to take targeted action to reduce consumption. In part such action may be behavioural - encouraging people to turn off the lights for instance, but there are also many cost effective solutions that are more effective than the human memory!

As energy costs rise and the affects of energy performance certificates begin to take hold, action to reduce consumption will become more common. Again, it is at the sub distribution board where  you can take effective action.

We are finding the use of DIN rail mounted control devices such as time switches, lighting dimmers and twilight switches are becoming increasingly popular.

Tesco Homeplus stores for instance use a combination of a master keyswitch, digital time switches and photocells to switch luminaires via contactors. The lighting circuits are split so that 40% can be switched on for cleaning and or shelf stacking, with the remaining 60% switched on when the store is open to the public. The photocells will also turn the lighting on or off in response to natural daylight levels from the rooflights.

More sophisticated control systems also use the final circuits at the distribution board to control electrical consumption. Bus based systems for instance switch loads in response to commands from other devices. Again many of these bus devices can be fitted to DIN rails. The demand for more control devices means the distributions boards must have a range of extension boxes as part of their suite. Ideally they should be modular so that the installer can easily fit them on top, below or on the sides of boards.

In addition, the more circuits that a board has the finer the level of control available to the designer. It may be that separate lighting circuits are used for those luminaires nearest the windows for instance so that they can be switched or dimmed in response to natural daylight.

One thing is certain, the demand for metering and energy control is going to increase in the next decade. As one management guru said, "If you can't measure it, you can't manage it!" 
The challenge for electrical designers and installers is to help building operators both measure and manage energy consumption. The role of electrical sub distribution is at the heart of this process. It is time for manufacturers to introduce boards that make this job simpler to achieve.

ERACS is an integrated suite of programs allowing loadflow, fault, harmonics, protection co- ordination, arc flash and transient stability studies to be carried out via the graphical user interface. The network single line diagram and data is entered only once. All calculation programs are operated and results viewed via the single line diagram, in addition graphical output is used where appropriate (e.g. protection, harmonics & systems stability).

In uninterruptible power supplies (UPS) resilience is the capacity of a system to adapt to hazardous conditions by resisting or changing to maintain an acceptable level of function and operation. It is also known as fault tolerance.

There are three key elements to UPS resilience:

  • The use of multiple power paths to ensure ac supply continuity (even during maintenance).
  • The ability of power protection systems to clear fault conditions.
  • Achievement of the lowest number of single-points-of-failure.

In this article, Robin Koffler, general manager of Riello UPS, examines uninterruptible power supply reliability and resilience and highlights the issues electrical engineers must take into consideration when designing UPS systems to ensure the result is the most reliable and resilient possible.

Designing resilience into a power protection solution is easier, less costly and disruptive at the outset, rather than retrofitting an existing system. UPS resilience levels are affected by the topology chosen and its distribution. Online UPS include an automatic bypass and therefore a safe failure to mains mechanism - not present in line interactive or offline designs. Online UPS (above 10kVA) are also capable of parallel operation, which provides additional capacity and redundancy. Dual input supplies and static transfer switches can be incorporated to strengthen overall system design but should not be considered viable options as alternatives to UPS in their own right.

Firstly, the category of load will directly influence the need for resilience and redundancy in the power protection system. There is little point implementing high levels of redundancy and thus wasting capital expenditure for loads that are none-essential or not critical to business continuity; canteen and printing facilities for example. However, computer, security, fire suppression, safety and building management systems must be kept going at all costs and so are classed as either critical or essential and require UPS redundancy, or in certain cases, the highest levels of redundancy. Redundancy comes from having a power protection system that has itself a ‘backup', which could be parallel UPS and/or an alternative power path and bypass.

Reliability measures include meantime between failure (MTBF), which needs to be maximised and meantime to repair (MTTR), which must be minimized. Another measure is availability of protected loads, which is not the same as reliability and is defined, in percentage terms, by a series of nines, five nines (99.999%) and six nines (99.9999%) being the most desirable level to attain.

The various UPS configurations, including single, parallel and series redundant will each offer a different level of resilience, MTBF and availability. Other aspects to consider are bypass arrangements, the selection of a shared or common battery set and distribution of power to the loads themselves.

Single UPS Installation

This is the most common form of UPS below 10kVA. It has one power path, a single ac supply, normally mains, which can be supplemented by a standby generator. The single power path represents a single-point-of-failure, which can be removed using a dual input supply. This configuration provides no redundancy.

The field population calculation MTBF for a typical online UPS is 250,000 hours (which varies between manufacturers). However, this reduces to just that of the mains power supply (50 hours) when the UPS is bypassed and the load is connected directly to it. Typically, this type of uninterruptible power supply would be implemented for non-essential loads.

Parallel UPS

There are two primary types of parallel UPS configuration: parallel-redundant systems (N+X) and parallel-capacity (N). Parallel-redundancy describes an uninterruptible power supply comprised of two or more UPS modules that equally share the load during normal operation but that can take over the total load should one or other of them fail during a mains power cut. It is the most commonly implemented solution for mission critical applications. MTBF ratings for this type of configuration are ten times higher than a single UPS. When designing such a system, the trick is to get the sizing of it just right, allowing enough spare capacity within each module so that they can power the total load if required but not so much that they run inefficiently. Too little and an overload will cause the static switch bypass to be triggered; too much and the capital cost of buying the extra capacity has been wasted.

A parallel-capacity UPS is created when multiple modules are connected in parallel but without redundancy. This type of configuration does not increase system resilience.

Series Redundant UPS

Series redundancy occurs when two UPS modules are connected so that either a) one directly feeds the other, which would typically be used for low power applications or b) the output of one uninterruptible power supply module is used to supply the bypass of another, which is also known as a ‘cold standby' arrangement. If one UPS fails the other automatically powers the load.

The disadvantages of series redundancy are inefficiency and cost and a single-point-of-failure. The configuration is less efficient than the two parallel configurations because series redundancy requires the UPS modules to be significantly oversized, which means higher capital and installation costs.

Automatic Transfer Switches (ATS)

For UPS below 10kVA that cannot be operated in parallel, automatic transfer switches can provide resilience. An ATS has two ac input power sources, which can work in three different ways:

  • One power source can be supplied from the output of a UPS and the other from the mains.
  • Both can be supplied from two separate UPS outputs.
  • Both can be supplied from two separate mains sources.

When one of the power sources fails, the loads are automatically transferred to the second. This is instantaneous when the two supplies are in phase with one another. An ATS can also provide protection against load short-circuits and can be powered on and off remotely (over a network). Its load can be measured locally via an LCD panel or built-in sub-D type communications port. Hardwired versions for higher operating power are also available.

The key to designing the most reliable and resilient UPS system is to take each and every element of it and ask the following questions: if this component fails in a power cut, will the loads still be powered? If the answer is "no" and it's a critical or essential load, design redundancy into the uninterruptible power supply by introducing another power path, installing a parallel-redundant system and closing off single-points-of-failure.

By Terry Cantle, managing director, FDB Panel Fittings

At FDB Panel Fittings we have many years of combined experience in supplying panel hardware, from which we have found the selection process for correct panel hardware is largely to do with the application. For example, there is little point in fitting low cost, light duty locks and hinges to enclosures destined for use in shipbuilding or mining. Of course they will work for a short time but not for very long. Conversely, it should not be assumed fitting expensive stainless steel fittings is the answer. As with most things, the optimum solution is based on more than one factor - and can make very important differences in cost and reliability - this is where FDB is able to provide independent advice and can often act in a project management role - finding an optimal application solution. Balancing weather-ability, corrosion resistance, strength/ruggedness and supply constraints, for example, by matching a stainless handle with a polyamide housing, as a compromise of performance/cost between polyamide at the low cost end and stainless at the high cost end.

A good example is the latest ‘buzz' technology in enclosure hardware - compression locking, which was confined to a somewhat limited range of applications until it recently came out of patent protection, so now a much wider market is finding it beneficial. A number of manufacturers seem to have had their own parallel version of this technology under development for some years and have been able to quickly bring their expertise in design/manufacture to provision of a very greatly expanded range of compression latch variants.

However the question ‘is a compression facility beneficial and where?' stands. The anti-vibration role of these locks is excellent in preventing opening of panels such as on trucks, railway rolling stock gen-sets, air-con and heating and ventilating systems.

Similarly the ability to provide soft gasket compression is valuable on cabinets with EMC gasket to ensure a firm contact, or indeed on large door panels where the closure force needs to be distributed over substantial distances or adjusted to allow for manufacturing tolerances, also compression technology provides several millimeters of soft gasket compression and cam depth adjustment.

The result then is that FDB customers are finding they are also now in a position to consider soft-close compression technology for ¼ turn locks, swing handles, T handles etc, where it may be that the different closure feel is important, or that the additional degree of anti-tamper performance conferred by the design is a valuable security factor.

This is just one of many trends in cabinet hardware which tends to work over fairly long time frames. During recent years there have been many new developments in enclosure hardware and today there are products available for almost all industrial applications. Not just locks and hinges but a whole raft of complementary products including grab rails and handles, stays, door seals and numerous accessories.

IPxx degree of sealing is, by now, a well recognised front line consideration and most engineers will be aware, for example, IP54 or IP55 - while potentially suitable for external use - is not weatherproof or waterproof. FDB has become adept at looking beyond this to the complete picture including: frequency of use, ease of operation, degree of corrosive environment, the cost/material balance, key possibilities, zonal security requirements, walk-by clothing entanglement, gloved hand usage, vibrational considerations, for example where vehicle mounted, wash down and pressure hose use, type of gasket used, door type and opening required, special industry standards, for example in railway, offshore, mining, machine tool guarding.

A major long term trend is toward greater use of stainless steel hardware; consequently FDB Panel Fittings has a  range of stainless steel locks, hinges and handles suited to petrochemical plants, hospitals, food processing establishments, medical environments, outdoor installations, marine and offshore industries. The range includes piano hinges, integral recessed lock/handles, weld-on hinges, bolt-on hinges, grab handles, spanner locks, rod locks, concealed hinges, lever and T handles. Importantly for marine/offshore installation many are available in stainless grade 316 as well as the more common 303 and 304 with satin and electro polished finishes. Stainless steel fittings are suited to control cabinets, electrical equipment and instrument housings, especially where exposed to the elements or frequent wash down processes. These stainless products are of course designed to complement the standard range of die-cast and mid steel fittings and in many cases are interchangeable with them.

In one large project recently FDB Panel Fittings was called in to supply locks for the new T45 warships. Like any very large single community the T45s face security issues for their personnel, in this case the requirement was for a zone based wing lock system to cover personal lockers, wardrobes and other storage areas. With typically over 2000 locks on each ship a project based master key system was specified for crew cabins and furniture or lockers in communal areas.

FDB was able to carry out planning, supply, specialist project packaging, administration of coding/delivery and long-term backup support. Not only was it important to have a zoned security with key operated wing locks offering a very high number of ‘differs' - up to 5000 different combinations with master keys - it was also important the locks and keys were separately labelled for specific locations and delivered at a very early stage so they could be brought together later during final fit out.

Another good example was the requirement for quarter-turn latches to suit 18000 galvanised steel water meter boxes for domestic installation in the Middle East. For security, a plastic clip-in, quarter-turn latch was specified by the customer - simple to fit and, bearing in mind the quantity, relatively low in cost.

However, FDB felt the latch would be unsuitable for the service conditions that were likely to be encountered by the boxes. A small but extremely robust die-cast lock with steel cam was suggested for evaluation by the client.

In order to stay within the budget constraints it was proposed the lock be supplied zinc-plated rather than with its usual chrome-plated finish. A further problem was the very short delivery period for the boxes themselves - a period of just 3 months for the fully equipped boxes with a fixed completion date and no possibility of slippage with container shipment pre-booked. FDB was able to deliver at the required rate of 1500 locks a week, but after four weeks increased this to 2000 thus allowing the contract to be met in 10 weeks.

FDB has successfully tendered for the supply of panel hardware to many diverse and prestigious projects including: London's Millennium Wheel, the Channel Tunnel, a Russian oil pipeline, Hungarian buses, the Thames Barrier, a T45 Destroyer fleet and the London Underground flood defences.