Features

There are estimated to be about 10 serious flashover (arc flash) explosions and 30 flashover incidents involving injury per day in the US. The seriousness and scale of the problem has been recognised by the regulatory bodies there and resulted in the introduction of code 70E by the National Fire Protection Association (NFPA). This only addresses risk mitigation during the incident. It does not address how to reduce the risk of the incident occurring, argues Ross Kennedy, managing director of QHi Group

In the USA ‘live’ thermal imaging inspections on medium voltage switchgear, where they open the panels, is quite common. There are around 15 deaths a year resulting from contact with live switchgear in the US, according to statistics from the US Bureau of Labor and from industry.
NFPA code 70E attempts to mitigate the risk of death and injury by zoning the area and prescribing increasing levels of personal protection equipment (PPE). There is a common misconception that thermal windows offer protection against the effects of flashover (arc flash). This is because the manufacturers indicate ‘compliance’ with NFPA code 70, but this is only with the covers on, in other words, when not being used. With covers removed they do not offer protection and the operative needs full PPE protection. Bad connections are the single most common cause of flashover. These ‘bad’ connections cannot be detected other than thermally, hence the widespread use of thermal imaging. However, while being a significant technology step at the time of its introduction, thermal imaging does not resolve two key issues:
1) It is only periodic - usually one or two days a year.
2) it is measuring the temperature of equipment which is located inside the enclosure, from the outside, requiring correlation and operator experience. Locating infrared sensors inside enclosures enables 24/7 continuous thermal monitoring with on-going trend analysis and alarm thresholds, which can be easily integrated into any BMS system.
QHi Group’s Exertherm can be fitted by switchgear manufacturers and panel builders as OEM equipment into new power systems, or retro-fitted and subsequently expanded. Self-powered intrinsically safe infrared (IR) sensors measure the rise above ambient, with only the assumption being that the sensor body is at the same temperature as the local ambient temperature. Local signal conditioning occurs outside of electrical panels using wired or wireless data transmission to a monitoring computer with appropriate software.

This predictive technology is already successfully installed in numerous multinational blue chip organisations and data centres, and is becoming increasingly adopted as ‘best practice’ in providing a significant improvement over periodic thermal imaging for mission critical equipment operating in high downtime cost locations. Furthermore, in an arc flash situation, you cannot apply standard mean time to repair (MTTR) calculations because it may take one or two days to assess the damage, and on average, a minimum of say five weeks (= 840 hours) of downtime.
In conclusion, continuous thermal monitoring is the only safe and reliable method of avoiding not only flashover, but also the cost of litigation and settlement, which in the case of the death of an employee can be as high as $15.75m in the US.

Electronic loads draw power from the supply with high levels of harmonics in the current. For IT equipment this has started to reduce in severity and the situation has improved from typically 50% down to 30% THCD (total harmonic current distortion). However, even at the lower figure these harmonic currents can cause high levels of voltage distortion in transformers, emergency generator alternators and all forms of UPS based on rotating electrical machines. Rob Tanzer, Technical Support Manager at Chloride Power Protection explains

Impedance is directly proportional to frequency so it is the spectrum of distorted load current harmonics that dictate the level of voltage distortion. For example, high-order harmonic currents will produce higher levels of THVD than the same THCD produced from low-order harmonic currents. So it is both the quantity (%age load) and quality (harmonic spectrum) that drives the resultant THVD.

In the case study that follows we have used a 2/3 pitch-wound synchronous alternator. Unlike a transformer, whose impedance at each harmonic frequency is a multiple of that frequency, this type of machine (used in gensets and rotary UPS) has lower impedance to the Triplen harmonics. Hence the same current will produce higher THVD in a distribution transformer.

Gensets tend to be partially loaded with harmonic generating loads and often oversized so this study concentrates on rotary UPS. The machine chosen is rated at 800kVA and has very low impedance (sub-transient reactance or forward transfer impedance, if you prefer) of 6.1% at the fundamental frequency, 50Hz. This is ‘low’ in comparison to a typical distribution transformer (8-10%) or, more significantly, a standard diesel-genset (10-15%).

We shall model the changing level of voltage distortion in a Tier IV type computer environment – with dual-corded loads being fed by a dual-bus UPS system, each bus comprising an N+1 rotary based UPS system. We shall take 2400kVA as the system load being fed by 2x 4x800kVA UPS systems, so that each system is capable of delivering 2400kVA with N+1 (33%) redundancy.

The point of interest here is in the wide variation of the four load scenarios as the system changes state due to maintenance or failure: • Normal operation with 2x(N+1) systems running at a maximum of 50% of the system load and the loading on the UPS is 38% • Maintenance in one system by removing one module from service, resulting in that system running without the +1 redundancy but still with <50% of the system load and the loading on the UPS is 50% • Maintenance in one system by a total shut-down (e.g. annual inspection) such that the other system carries the full load, with N+1, and the loading on the UPS is 75% • Emergency mode – one system out-of-service and the other system without N+1 redundancy, with the loading on the UPS at 100%.

To analyse the THVD we need to predict a load current profile. Fig. 1 (all figures below) shows the 1920kW full load with 32% THCD and CF=1.83. The Displacement (Power) Factor of such loads today is close to unity. On the right of the diagram is shown the harmonic spectrum. The distortion factor calculation (and for completeness the Neutral Current profile) is shown in Fig. 2. It is interesting to note that the Neutral Current is only 76% of the phase current with this modest harmonic load.

Results
In Fig. 3 the system is modeled in ‘normal’ mode, all systems running with full redundancy. With 3200kVA capacity of UPS feeding 1200kVA of load the overall effective impedance is very low at 2.29% and hence the resultant THVD is 5.34% - although specific IT hardware OEM’s would regard that as excessive.

In Fig. 4 one module has been removed (for maintenance for example) and, as the overall impedance rises, the THVD rises to 6.62%, well above the normally acceptable 3% in most National power systems. The obvious distortion will not find favour with IT OEM’s looking for a high-fidelity voltage waveform and will cause heating in cables, transformers, motorwindings etc.

Next we come to the less frequent ‘emergency’ conditions – although it has to be said that this is what the client is actually paying for via the high levels of infrastructure redundancy.

Fig. 5 shows the system’s response to the full load being transferred to one of the two buses. This could occur under system failure or, more likely, should occur during the annual maintenance shut-down. The resultant THVD has now risen to an unacceptable 9.18%, even though the machines are still only loaded to 75%. Lastly, in Fig. 6 the ultimate emergency mode prior to load loss through UPS shut-down (and then the load might be transferred to mains or generator where the THVD will be markedly worse) – where the load is carried by one system which has lost its redundant module. The THVD is an un-operational 11.74%.
Conclusion It should have become clear that rotary systems’ critical output THVD is 100% load dependent (both harmonic spectrum and quantity). Unless the client can specify the loads harmonic profile the THVD will be unknown until after startup.

If the spectrum contains larger proportions of higher-order harmonics than those modeled above then the THVD could be far higher.

If the load conditions are known then a rotary system can be selected that will produce acceptable levels of THVD (generally by over-rating and achieving a lower impedance) under all operating conditions. In general the system designer should be aware of the dangers of loading rotary UPS to high levels with high-order harmonic loads – say in Tier II systems with no redundancy. Also the smaller the rotary machine generally the higher the fundamental impedance so, for example, putting 500kVA of the above load onto a 500kVA solo-machine produces nearly 20% THVD whilst 250kVA of the load still produces 10% THVD.

On the other hand, due to the PWM algorithms of the IGBT inverters all forms of static UPS, both series-on-line (double conversion) and line-interactive, will control the output voltage sine-wave to around 3% and always be less than 5% regardless of harmonic spectrum or percentage load.

Geoff Brown, Drive Applications Consultant, ABB Limited

Servo drives are generally used in applications requiring high precision, for example machine tools, and other high-precision machinery in industries such as material handling, packaging, paper, textile and woodworking.

The majority of servo drive solutions utilise a motor with low inertia rotor to provide rapid torque or speed response, and these motors may use permanent magnet or brushless d.c. technology, together with, a feedback device in the great majority of cases to give high accuracy. In addition to the motor the controller or amplifier traditionally has little programmability, and relies on an external controller.

But like many other areas of drive technology, the servo drive is being challenged in its market niche by standard AC drives that are becoming increasingly accurate and provide high performance at a lower cost. There is a new class of machinery drives around that is able to run a standard AC motors as well as specialist servo motors, with or without feedback devices, using a single drive platform.

Historically servo motors have used “square frame” construction, reminiscent of d.c. motors, and a range of “square frame” asynchronous motors matching d.c. motors has also become available. These can readily incorporate fixed speed fans, encoders and brakes.

This gives the designer an opportunity to select the most cost-effective solution amongst a range of options – servo, square frame or standard squirrel-cage motor, with feedback or without, depending on the requirements. The same type of drive can be used throughout the application, regardless of performance requirements.

The biggest leap forward for conventional drives in recent years has been improved torque control as a result of more powerful processors; this has enabled them to be used in the high performance arena. More computer power means quicker execution. This has opened up a.c. drives and motors to applications with a wide speed range, for instance dropping to a dead speed and then rapidly accelerating to high speed.

This all means that the required performance can often be achieved with standard AC motors without feedback devices, and drives with on board functionality, reducing the cost and complexity of the installation. If higher performance is needed, then a feedback device can be added to the standard or square frame a.c. motor. For still higher performance, add a servo motor, with low inertia rotor. For the highest performance achievable, a servo drive will still be needed. But for many applications, the performance needed can be achieved more simply and at a lower cost.

This is a good time to shop around for a high performance drive at a reasonable cost. Don’t just instinctively reach for the servo drive option, ask your drive supplier for advice.

Recently the trade and industry secretary, Alistair Darling, released the energy white paper, which sets out the details of the government’s energy strategy for the years - and decades - to come. Among the issues discussed are security of energy supply and the environmental impact of energy policy, but not apparently whether future government ministers will be given a fleet of Jags to take their wives 100 yards down the road. Open Circuit looks at some of the less well-known elements of the strategy…


Badly lit tunnels and incomplete diagrams were among the obstacles encountered by Geoffrey Lilleker an engineer working on a hydropower plant in the Himalayas’ foothills as he told Electrical Review


Located on the river Satluj in the north east of India this is a run of the river scheme to provide up to 1500MW of power from 6 machines at the village of Jhakri. The water is directed from the dam site at Nathpa via a 26km tunnel including 3 silt flushing chambers all dug into the mountains that are a part of the foot hills of the Himalayas in that part of Himachel Pradesh.

His brief initially, was to provide the software package for a number of Allen Bradley PLC systems that were to control the silt flushing gates and the guard valves in a tunnel with a length of 26km leading from the Naptha dam to the village of Jhakri where six machines were due to deliver up to 1500MW of electric power. His brief also comprised the electrical commissioning of the ports at the dam including the radial ports as well as various gate hoists that cut off individual areas off the plant for maintenance work and in case of an emergency.

“Unfortunately the drawings I was provided with locally were causing me many problems! They were out of date which meant there were many instances where they did not match the equipment supplied. Because of a shortage of relay contacts extra relays had been added which were not even shown on the drawings. Many device terminal numbers were missing making it difficult to follow them. Perhaps worst of all, the drawings had been done on a package that allowed more and more devices to be added to the same sheet by scaling the existing drawing down, which meant when they were printed out they could only be read with a magnifying glass. When a lot of the job involved working in poorly lit tunnels underground this was obviously an impossible situation. By the very nature of commissioning many circuit modifications had to be made, which also needed incorporating accurately into the drawings for final issue to the client and included into the of maintenance manuals,” Lilleker said.

“The nights were long in that remote part of the world,” he continued, “Using Elcad I could create all electric drawings from scratch in a short time. Thus, to the immense relief of the customer, the huge project was saved in time, and with new complete and safe documentation.”

Jim Wallace, research and technology manager at Seaward Electronic explains the importance of ensuring the safety of electrical appliances and equipment used in the workplace


The safety testing of electrical appliances and electronic equipment on the production line has become an integral part of the manufacturing process - but what happens when those items leave the factory for ‘in-service’ use in a factory, office, construction site or other type of workplace?
Although there are legal duties on manufacturers and suppliers covering the performance and integrity of new electrical or electronic equipment, responsibility for the safe operation of equipment in the workplace rests firmly with the employer.
The HSE claims nearly a quarter of all reportable electrical accidents involve portable and transportable electrical equipment and reports around 1000 workplace electrical accidents each year.
Poor electrical installations and faulty appliances are also a major cause of workplace fires that are responsible for extensive property damage, as well as posing a further risk to staff. For example, faulty equipment and leads have been known to cause over 6000 separate fires a year

SHOCK TACTICS
Records indicate that a large number of workplace deaths and injuries are due to electrical shock from misused or faulty electrical equipment and most could have been avoided if proper electrical checking procedures had been applied.
For example, how can gradual deterioration in the electrical integrity of a power tool be identified or a potentially dangerous fault in a vending machine, kitchen appliance, or other electrical item be diagnosed?
The following examples on the effects of current on the human body are worthy of consideration:
0.9 – 1.2mA ~ Current just perceptible
15.0 – 20.0mA ~ Release impossible: cannot be tolerated over 15 minutes
50.0 – 100.0mA ~ Ventricular fibrillation, leading directly to death
100.0 – 200.0mA ~ Serious burns and muscular contraction of such a degree that the thoracic muscles constrict the heart.
When these values are compared to the fact that 250mA of current is required power a 25-watt lamp, the lethal potential of a faulty electrical appliance is easily understood.
The Health & Safety At Work Act 1974 puts a duty of care upon both employer and employee to ensure the safety of all persons using the work premises. However, the particular legal requirements relating to the use and maintenance of electrical equipment are contained in the Electricity at Work Regulations 1989 (EAWR).
Regulation 4(2) of the EAWR requires all electrical systems be maintained, so far as reasonably practical, to prevent danger. This requirement covers all items of electrical equipment including fixed, portable and transportable equipment – essentially anything connected to a building’s electrical system with a plug.

PASS OR FAIL
Although people carrying out the testing of portable electrical equipment should be appropriately trained for this work, since the introduction of the EAWR many electrical contractors have set up specialist portable appliance testing operations – as have other FM companies and electrical service firms.
Other organisations have responded with the introduction of in-house testing protocols managed by electrical engineers, maintenance managers, safety engineers and/or site electricians or facilities management personnel.
Whichever way it is implemented, planned and proactive safety policies must be capable of detecting potential problems with electrical appliances before they occur and this is the role of preventative maintenance programmes.
The majority of equipment defects can be found during visual inspection – the HSE says that just looking can identify 95% of faults or damage. For example, a detailed examination by a competent person is likely to eliminate hazards caused by cable or plug damage, faulty wiring or other obvious signs the equipment’s condition could create faults or a danger to users.
However, to identify all potentially dangerous faults, visual inspection needs to be linked with a programme of periodic inspection and testing that is capable of revealing any ‘invisible’ electrical faults such as earth continuity, insulation integrity, correct polarity, unacceptable earth leakage and other potential problems.
Clearly such combined inspection and testing measures should be appropriate to the particular risk posed by the equipment and its environment. This means maintenance procedures in some commercial environments might be required less frequently than in other high risk environments such as factories, engineering or industrial premises and construction sites – but will still be needed to verify safe working conditions.
For example, smaller offices or similar workplaces with only a few electrical appliances might be regarded as relatively low risk environments. Here, a responsible attitude might be regarded as a regular process of formal user checks and visual inspection, combined with some limited periodic testing.
A different view, however, might need to be taken in a large commercial operation or by an engineering or manufacturing organisation, with different departments and having many different types of electrical equipment used by staff. In this case, ensuring the safety of appliances may not only be a matter of ensuring the correct test equipment is available, but also having the ability to show that the right tests have been performed at the right time in the correct sequence - with records of test levels and results.
Also, overall frequency of inspection and testing of equipment will depend on whether the electrical items are rated as Class I or Class II and in what environment they are used. For example inspection and testing of some types of industrial and construction equipment might be advisable every 1-3 months and the interval can range to up to 12 months for other industrial locations, commercial kitchens and other workplaces, to 24 months and above for hotels, some offices and shops.

TESTING, TESTING
Cost effective maintenance of portable electrical equipment can therefore be achieved through a combination of user checks, formal visual inspection and electrical testing.
Combined inspection and testing programmes require greater level of competence than for inspection alone. However, a range of portable appliance testers (PATs) are available that make the in-service safety testing process safe, fast and easy to carry out.
Test instruments are available which range from the relatively simple to operate pass/fail checkers which will carry out some of the basic safety checks on equipment to provide an immediate ‘go/no go’ display.
However, for more comprehensive test requirements, microprocessor controlled testers are available that combine user-friendly operation with a whole range of other features for particular test demands or routines.
Lightweight testers are now available that incorporate all Class I and Class II required electrical safety tests in a compact hand held instrument. Long life battery power eliminates the reliance on mains outlets for testing, making the instrument totally portable and suitable for universal testing applications.
The incorporation of Bluetooth technology in some modern testers allows the wireless connection of bar code scanners, label printers and other accessories – allowing totally cable-free testing, without the cumbersome and constant plugging in and unplugging of leads and cords.
In addition, the latest generation PAT testers also have the facility to record the results of other safety management data including emergency safety lighting conditions, or condition of fire extinguishers, for example, as part of more comprehensive safety equipment audits.
Although there is no formal requirement in the EAWR for records, the HSE does recognise that some records of maintenance and test results is a useful management tool for reviewing schemes and demonstrating that safety policies have been enforced.
The use of computerised portable appliance testers also enables test data to be transferred directly from the instrument to a PC-stored database allowing an automatic update of test records, the generation of test reports and advance testing schedules.

EFFICIENT TESTING
Against this background, for the electrical contractor offering PAT services the pressure to complete tests quickly is immense. Those companies that have succeeded recognise the need to combine a fast effective service with the proper quality of testing.

To help them do so, a new safety-testing concept has been introduced to help those involved in PAT testing the ability not only to work smarter – but to improve their productivity and effectiveness in the process.
The PATSolutions approach seeks to streamline the selection of integrated portable appliance testing systems by bringing different test elements into distinct product packages.
Linking hand held test instrumentation with new technology and service support, different packages have been introduced to meet the different test system needs of facilities and safety managers or service engineers that carry out in-house electrical safety testing.

At each level a choice of test instruments are provided in keeping with the sort of portable appliance testing being undertaken. The testers are supplied with various accessory and software options, together with service and calibration support.

With growing awareness of the importance of the safety of electrical appliances, many private and public sector organisations have come to recognise the importance of regular inspection, test and maintenance of all electrical equipment used in the workplace.

Thermal images of electrical systems can rapidly indicate the operating condition of electrical equipment. In fact, since the beginning of thermography more than four decades ago, the principal commercial application for thermal imaging has been electrical system inspection says Ken West of Fluke (UK)


Thermal imaging has typically been the exclusive domain of specialists in the field, and has required the use of costly and difficult to operate equipment. With recent advances in sensor technology, this non-contact, versatile measurement technique has become available to a wider audience through dramatic reductions in price and in developments of user-friendliness.
Essentially, thermal imagers locate potential problems by detecting temperature differentials between one location and another. This can be achieved with instant displays of data using today’s handheld imagers which employ ‘point and shoot’ technology from an ‘electrically safe’ distance.
By presenting a rich visual image, using colours to represent a temperature, thermal imagers facilitate a quick visual check of surface temperature and easy identification of hot spots, which are often an early indication of impending failure. Maintenance programs can be developed and re-traced periodically using in-built routing instructions on the best products now on the market.

Warning signs
New electrical components begin to deteriorate as soon as they are installed. Whatever the loading on a circuit, vibration, fatigue and age cause the loosening of electrical connections, while environmental conditions can hasten their corrosion. All electrical connections will, over time, follow a path toward failure. If not found and repaired, these failing connections lead to circuit faults.
The reason thermography is so applicable to the monitoring of electrical systems is that a loose, over-tight or corroded connection increases resistance at the connection and since increased electrical resistance results in an increase in heat produced, a thermal image will detect the developing fault before it fails. An unbalanced or overloaded phase will also show up as hotter compared to the other two phases.

Preventative maintenance
Detecting and correcting failing connections by comparing the temperatures of connections within panels before a fault occurs averts impending failures. The best solution is to create a regular inspection route that includes all key electrical panels and any other high-load connections. The latest thermal imagers enable capture of data which can be uploaded and stored on a computer at the end of an inspection and then compared with other measurements over time. The ideal imager will allow the images from the previous inspection to be downloaded, so that previous and current images can be compared side-by-side at the point of capture. This will help to determine whether a hot spot is unusual or not, and also help to verify that repairs have been successful.
Such predictive actions are important because when a critical system does fail, it inevitably increases costs, threatens a client’s profitability and may impact on safety.

What to look for?
In general, connections that are hotter than others should be looked for. This signals high resistance possibly due to looseness, tightness or corrosion. Connection-related hot spots usually (but not always) appear warmest at the spot of high-resistance, cooling with distance from that spot. Overheating connections can, with additional loosening or corrosion, lead to a failure and should be corrected. Equipment conditions that pose a safety risk should obviously take the highest repair priority.

3-phase problems
Thermal images are also an easy way to identify apparent temperature differences in three-phase electrical circuits, compared to their normal operating conditions. By inspecting the thermal gradients of all three phases side-by-side, engineers can quickly spot performance anomalies on individual legs due to unbalance or overloading. Even a small voltage unbalance can cause connections to deteriorate, reducing the amount of voltage supplied. A severe unbalance can blow a fuse, reducing operations down to a single phase. Overloading or unbalance should then be investigated using other types of measuring instruments such as a clamp meter or power quality analyser.

Reporting procedures
Analysis and reporting software is provided with the best thermal imagers. Whenever a problem is discovered using a thermal imager, this software should be used to document the findings in a report, accompanied by each thermal image and a digital image of the equipment. This is the best way to communicate the problems to the client along with the suggested repairs.

Keeping ahead of the game
Thermal imagers at affordable prices offer one more tool in the arsenal of the maintenance engineer who wants to keep one step ahead of the game by offering his clients even better preventative maintenance.

Increasingly demanding applications have driven the innovation of new products to set new industry standards. The electrical control enclosure in today’s technological environment needs to address an array of different applications and when considering which enclosure is suitable for an application, the basic enclosure is now only the starting point says Sando Selchow of Rittal


Within manufacturing process environments electrical enclosures are often situated in close proximity to the actual products being produced. The mechanical components used in and around such process plants tend to accumulate deposits and the electrical enclosure is no exception, with particles possibly cultivating on enclosure surfaces, crevices and recesses. If this were a food, pharmaceutical or chemical plant a strict hygienic protocol would need to be adhered to in order to prevent contamination. Maintaining a hygienic working environment in this type of environment although of paramount importance is always a constant battle.
Rittal has recently introduced a new range of hygienic design enclosures to facilitate in this constant battle. The range has been specifically designed to prevent deposits cumulating on the enclosure surfaces, crevices and recesses to help eliminate any potential contaminants, which could negatively impact on customer production.

Incorporated into the design is a 30° angled, sloped overhanging roof preventing any liquids or solids collecting on the roof area. A larger than average gap to the top of the door, allows for easy cleaning and prevents any unwanted deposits from reaching the door seal. The door has outward pointed edges (approximately 135° compared with 90° folded standard enclosure doors) and a larger flat surface on the inside of the edge. Together with the flat silicone base seal, the door builds a perfect corner finish, free of gaps and contact areas preventing any unwanted deposits.

The enclosure has a protection category of IP66, which also includes the internal door hinges to create an all round gap free door. The new flat gap free silicone door seal is coloured blue, which is the industry standard colour for non-consumable products, and offers a high resistance to all process and cleaning liquids.

Various different mounting options are available. The enclosure can be mounted either with tubular mounting brackets with a smooth finish, or open frame plinths with a clearance height of 300mm, designed from tubular stainless steel. Both options allow easy cleaning access and minimise entrapment areas. Adjustable levelling feet, with internal sealed threads, make entrapment areas completely obsolete and new stainless steel cable glands stop any particles from attaching themselves within the glands or connections.

Electrical enclosures, which are used in hostile situations in the manufacturing process environment, are usually hosed down at the end of the day. Often high pressure cleaning equipment is used and the mechanical equipment or controls are included in this wash down. In this type of environment where the controls need to be protected against any form of water ingress it is recommended that a stainless steel sealed enclosure be used which meets the demanding standards of IP69K.
More stringent cleaning methods are required within food processing plants where strong high velocity hoses are directed at machinery and their controls to prevent harmful bacteria from harbouring. The temperature in a process plant within a poultry factory could be around 10ºC ambient when in use, but when the cleaning process takes place, refrigeration is turned off, which allows the temperature to rise to 20ºC. The water temperature for cleaning is often higher than 50ºC and can have a water pressure of 70 bar. If the enclosure to house the controls was only rated at IP56 or 66 the control enclosure could fill with water, as the water temperature is far higher than the enclosure and the water pressure is greater than the design standard of the gaskets.
The IP69K protection category certifies the enclosure to be water ingress proof when tested on a turntable. The German DIN 44050 standard originated from requirements found in the automotive industry where spray water and high pressure cleaning resistance was required.
The IP69K to DIN EN 40 050 part 9/5.93 lists the IP (International Protection) rating for road vehicles. The IP rating is described in a combination of the two numbers and an additional letter behind the last characteristic numeral. In this case this creates for example the IP69K, where the letter “K” provides further information. The letter “K” refers to a special case for road vehicles which describes the protection of electrical devices in road vehicles with regards to foreign bodies, dust and, in particular, with regard to the penetration of water. The use of the additional letter “K” is, however, no longer used exclusively in vehicular applications, but also in the food and beverage processing industries. As this test procedure differs considerably from the other IP-tests, enclosures with IP69K test certificates are currently the highest protection standard available against water ingress.

The IP69K to DIN40 050-9/5.93 lists the protection category test consisting of the following parameters: Water pressure up to 100 bar; 14-16 litres per minute flow rate; temperature up to 80°C; distance min 100 to max 150mm. Duration of the test calls for 4 directions and test jet time of 30 sec each at the angles of 0°, 30°, 60° and finally 90°. To achieve the 4 directional test, the test object is placed on a rotating turntable.

Protection class IP69K is therefore an important standard for enclosure systems used in the food industries. In addition to the water ingress properties, the food industry also requires hygienic standards on the surface properties. Standard 304-grade stainless steel achieves the required levels, but what about the gasket material? Special properties are required, such as a non-bacteria harbouring surface and a smooth transgression between the stainless steel parts and the gasket materials. The German Institute, “Frauenhofer-Institute IPA”, certified the highest standards in the food and hygiene sector for the Rittal IP69K enclosure range.

When products are used in factories and applications around the world, common safety standards are set to make sure all health and safety criteria are met. Enclosures are no exception; meeting the requirements of the EN60529 ingress protection and EN60439 low voltage control gear assemblies standards.

New markets have also given the enclosure manufacturer the ability to supply complete packages. There are a wide range of different climate control solutions available that range from addressing condensation issues to more severe heat problems, heaters for raising temperatures above freezing, louvers for normal convection, fans for forced convection along with air-to-air heat exchangers, to technically sophisticated cooling systems for the more hostile environment. Power distribution can also be a prerequisite in control panels and a busbar system that offers advantages in assembly and space saving is an advantage providing possible cost and time savings.

Rittal’s extensive range of climate control solutions feature two control options that allow functions such as door switch control, condensate management, master-slave set-up, and network connectivity, as well as a wealth of system information that can be accessed and evaluated. On three phase units, the systems accept both 400 V and 460 V +-10% connections from one single standard unit. The internal air circuit design of the roof-mounted units can open up more possibilities in drive cooling applications or targeted cooling.

Rising costs and a very real danger of future energy rationing are pushing the need for UPS systems to be correctly sized further up the agenda says Robin Koffler of Riello UPS (right)


Thermal imaging has typically been the exclusive domain of specialists in the field, and has required the use of costly and difficult to operate equipment. With recent advances in sensor technology, this non-contact, versatile measurement technique has become available to a wider audience through dramatic reductions in price and in developments of user-friendliness.
UPS customers are being urged to be energy efficient and play their part in tackling climate change. They cannot afford to have equipment, including UPS systems, running inefficiently nor can they risk an overload situation from ‘undersizing’ that would render equipment unprotected.
This is particularly true in power-hungry data centres where energy consumption in the business world is at an all time high. Not only do new, high-end servers require more power to operate, they also demand greater cooling resources. Every megawatt required to power hardware takes another 1.5Mwatts to cool it according to some reports. The need to prepare for the future is vital as electricity costs over the next five years are set to double, say analysts: In a recent report, consultancy BroadGroup found that the average energy bill to run a corporate data centre in the UK is around £5.3m/year. The company predicted that this would double to £11m over five years.
But is sizing UPS really down to simple maths? There has been a tendency, historically, to oversize UPS to ensure that, when everything is working at full capacity, the system itself is not overloaded (a situation to which some UPS respond by shutting down after a specified period of time, if it’s a double-conversion design, or at best by switching into bypass mode until someone notices, thus leaving critical computer systems vulnerable to cuts in the power supply or problems associated with raw, unfiltered mains energy).
Oversizing UPS leads to higher initial installation and on-going maintenance costs. Undersizing, especially in a busy data centre where new equipment is being continuously added and fluctuation in usage runs up and down the scale like fingers on a Cello, a customer will very soon be in trouble if they attempt to save costs in this way.
Whilst an On-Line UPS has a built-in automatic bypass, running close to its design limits with regular overloads is never considered good practice. The bypass is for emergency situations only and if overloads are a frequent and regular occurrence, it is always best to oversize the system slightly.
According to business continuity supplier Sungard, the proportion of business continuity plans invoked by companies experiencing power failures jumped from 7% in 2005 to 26% in 2006. The reasons for this may be three-fold: either energy supply is becoming less reliable, or existing UPS installations are unsatisfactory or - worse still – non-existent!
So, what needs to be done to ‘rightsize’ UPS? Firstly, the equipment that is being protected (defined as the ‘load’) has to be categorised into critical, essential and non-essential loads.

Critical Loads
Are defined as all the IT and electrical components and equipment that make up the business architecture and without which business continuity would be lost. Servers, routers, computers, storage devices, telecommunications equipment, security and building management systems usually fall into this category.
In this instance, UPS protection will probably require some form of extended runtime to keep equipment running continuously, more often than not it will also require redundancy so that if a power failure occurs and one UPS goes out of action, the other would take over powering the load.

Essential Loads
These are essential to the business but in their absence some semblance of functionality can exist. Essential loads are things like lighting (other than emergency lighting), air conditioning and heating. Some essential loads may need some form of redundancy built into the UPS system but in many instances back-up does not need to be as robust as with critical loads.

Non-essential loads
Are those that the business can survive without for the time it takes to reinstate power, such as printers and canteen facilities for example.
There can be significant differences between the power ratings recorded on rear panel labels and in operating manuals, and the true values drawn by electrical equipment. This is because hardware manufacturers use power supplies rated for maximum, worst-case conditions which are often far in excess of the actual power drawn. Loads can typically be seen running at only 50-60% of this total capacity. In addition, any ratings given may be in amps or watts to further complicate matters and there can be quite a difference between actual in-rush (start-up) and running power requirements.
Factors that must be considered when sizing UPS loads include:
• Apparent power (VA)
• Active power (W)
• Power Factor (pf)
Other factors that need to be considered if the right UPS is to be installed include expected response to overloads, which should only be intermittent, battery runtime required, fault tolerance (resilience) levels to be reached, the type of electrical installation in terms of the supply and load voltage and frequency requirements and the potential for future system expansion.

Apparent Power
Volt-ampere (VA) is a unit of measure for apparent power drawn by an electrical device. Once known, this figure can be matched to an appropriately-sized UPS. VA is calculated by multiplying the RMS source voltage (V) by the current drawn in amps (A). apparent power (VA) = volts (V) x amps (A)
For example, if an electrical device is connected to a 230Vac single-phase supply and the current drawn by this device is 10 Amps, the resulting VA value would be: 10 x 230 = 2300VA or 2.3kVA.
For a three-phase load, the calculation is slightly different. A 15kVA three-phase UPS will supply a maximum of 5kVA per phase (15

A sensible leave of absence

My congratulations to Dr Timothy Stone. Who is Dr Stone, you ask? He has been the head of global infrastructure at consultancy firm KPMG. And is the man chosen by (shortly to be former) DTI Secretary Alistair Darling, to look after the entire nuclear clean-up.
Or to give the task its more formal title, to oversee “arrangements for the costs of new build, decommissioning and waste management.” And with clean-up costs alone now estimated to be well over £70,000m, he will have quite a task before him.
This month’s much delayed Energy White Paper repeats the government’s volte face on nuclear. Having spent the previous nine years bad-mouthing anything to do with the Great God Atom, last summer New Labour suddenly got religion, and declared itself in favour of lots of new nukes.
But with one crucial condition. Any new power stations must not only be built and run by the private sector, these private operators must be prepared to pick up the tab for handling all the consequent costs.
That is the brief Dr Stone has. Were he to fulfil it to the letter, it would undoubtedly infuriate his former colleagues at KPMG. At present, the consultancy makes millions from advising the different parts of the nuclear industry.
For instance, last year the firm won an award for its work on the sale by British Nuclear Fuels of its construction subsidiary, Westinghouse to Toshiba. Working it has to be said for the purchasers. In the judges’ words, “KPMG Corporate Finance used its contacts with the UK Government and BNFL to market (sic) the Japanese player.”
Wisely Dr Stone has not become a full-time civil servant to carry out his new duties. Instead, he has simply taken leave of absence from his former employers. Really, the last thing a consultancy like KPMG wants is somebody intervening on behalf of the UK government, trying to ensure all the relevant nuclear costs are carried by the private sector. I am sure that Dr Stone will bear that particular concern in mind in his new, temporary, role.


Gordon keeps it in the family

In his current seven week round tour of the UK, prior to becoming our prime minister, Gordon Brown has endlessly stressed how ‘family friendly’ his new administration would be. That will come as excellent news for the nuclear industry.
Take for instance Andrew Brown, younger brother of the aforesaid Gordon, who is chief spin doctor (whoops, press officer) for EDF Energy. Which has long been the only electricity company prepared to openly champion new nuclear stations. Possibly to do with being French-owned, and therefore heavily subsidised by the French state?
Or take Tony Cooper, the father-in-law of Brown’s right hand man Ed Balls, effectively our new deputy prime minister. A former general secretary of Prospect, covering employees in nuclear power stations, Cooper is still very active within the TUC, plugging away on the pro-nuke cause. And who should the present construction minister be? Step forward Yvette Copper, Tony’s daughter.
All that is needed now is for Sir Bernard Ingham, the one person member of SONE, Supporters of Nuclear Energy, to declare himself as Brown’s long-lost uncle, and the Happy Family pack will be complete.


Planning for the future

When a Minister creates a public body to award lucrative contracts to the private sector, he or she will of course never be giving any thought as to whether they might be able to benefit from such contacts when they leave office.
Take Brian Wilson, for instance. When, as energy minister in 2000, he set up the Nuclear Decommissioning Authority, it will never have crossed his mind that it might be advantageous to any private sector company bidding for such contracts to have an ex- energy minister on its board.
So it is of course as complete a surprise to him, as to everybody else, to learn the construction company Amec is bidding for clean-up contracts from the Nuclear Decommissioning Authority. Well, perhaps not quite as much of a surprise to Wilson as everybody else. Just a few months before the bid was made, Wilson joined the Amec board of directors.


Gas suppliers ignored by Ofgem compensation scheme

Any electricity consumer who spots a billing mistake, is entitled to £20 compensation from their supplier, if the matter is not dealt with speedily. The compensation kicks in if the supplier has not made a “substantive response”, known as an ESG10, to a query on charges and payments within five working days.
At least, that is true if you have remained with your initial electricity supplier. Quaintly, Ofgem only insists upon such compensation being available to those who reside within the suppliers’ home market. At a time when Ofgem seems to believe the main value of its drive to deliver ‘competitive markets’ is the number of households who switch suppliers, this restriction seems utterly bizarre.
But not as bizarre as the compensation levels required for those who find they have been incorrectly billed for their gas consumption. There is absolutely no requirement for Centrica, or indeed anybody else, to provide any such recompense at all.
I do not understand why this occurs. I do think Ofgem should explain.

By Nick Guite, director, Utilities, Construction and Professional Services at BT


For companies with a large number of mobile field workers, to say it is a challenge to keep in touch with their workforce whilst keeping them employed is probably an understatement. Yet, remarkably, many industries – not least those for whom the challenge is most acute, such as utilities, remain unaware of the rapid pace of technological change in this area, and the benefits it can bring.
Traditionally, or at least since the early ’90s, the communication and work scheduling challenge has been tackled by deploying a standard mobile phone coupled with a manual job allocation process back at headquarters. Perhaps not surprisingly, the results over the years have been mixed. Marked variations in customer service experiences and costly internal resource overheads make the traditional solution an inefficient and unsatisfactory one – and therefore no ‘solution’ at all.
Meanwhile, the evolution of technology designed specifically for mobile working – GPS (Global Positioning System) locators, mobile communications, automated work scheduling – has continued apace. Real solutions are out there. The problem has been that, even where they have deployed the technology, the pace of change may have outstripped businesses’ capacity to exploit it and reap the full benefits. Automating a force of field workers, essentially, is about improving service. That’s it. Or is it?
Certainly, getting the right engineer with the right skills to the right job at the right time is about making sure your army of people-on-the-ground are giving the best possible service to customers. As is improving productivity and responsiveness of service contact centres or keeping promises with customers by adhering to well-defined appointment slots.
But is it all about customer service? Is it just the customer that you should be thinking of? Or is the field force automation strategy, which companies like Northumbrian Water are embarking upon, where they are planning to roll-out field force automation (FFA) across the company’s fleet of approximately 900 vehicles and 1,100 field operatives over the next 12 months, slightly more complex?
As you’d expect in the 21st century, technology’s role in that strategy is increasingly critical, but is not in itself where the complexity lies. Behind the jargon and the esoteric acronyms, the technological process is actually rather straightforward. No matter the type of device being used, put plainly, it’s about connecting all the dots to reveal the – until now – hidden picture. The dots, of course, are a business’s field engineers, service representatives, or indeed any workforce that spends a large part of the working day out of the office and physically isolated from colleagues. And today, in 2007, that last aspect of the job is where the complexity of the issue lies. Giving HQ a full picture of where vehicles are, whether their engines are running, where workers are and what they are working on is vital not only for efficiency but also for duty-of-care to staff. The dangers of being ‘physically isolated’ whilst at work represent one of the most compelling drivers for adopting the type of field force technology which BT has developed for a number of utilities companies and fleet operators.
Working in remote or isolated locations or, particularly, working alone, carries inherent risks. Frequently, the areas in which service engineers, carrying money and valuable equipment, have to go to conduct critical repair or maintenance work are secluded and potentially threatening. Working in the dark, in bad weather, or in any unwelcoming environment can and does make field workers feel vulnerable. BT itself allocates 18 million jobs a year to 24,000 engineers and the reality is that as their employer it has a responsibility to ensure their safety.
The technology utilised to monitor field worker whereabouts and improve customer response times can equally be used to increase worker safety. One new solution is a round-the-neck ID card-sized device with an inbuilt GPRS SIM card – exactly like that which makes our mobile phones work. If entering a vulnerable area or situation, lone workers can put themselves on amber alert by sending an instant message that will flash up on HQ or customer screen – “I’m arriving at the back door” – or they can put themselves on red alert, whilst remaining discreet, and open a one-way voice channel that enables HQ to monitor them, and initiate support if necessary.
The value of such a straightforward piece of technology to a worker operating in a threatening environment is incalculable. The technology itself is, as it always should be, relatively simple – but sometimes the simple solutions are the best. And it is the responsibility of the companies developing the technology to explain it in simple terms.
Organisations are recognising the benefits of technology for their field workers. It’s worth remembering that those benefits do not only help customers, but extend to your own workers too.

Mike Henshaw of Omega Red Group, a company specialising in earthing and lightning protection, investigates


During the recession in the early 1990’s, hundreds of thousands of skilled and unskilled workers were lost from the construction industry. Since then only the most progressive companies have continued to make a significant training investment in their workforce and ensure that they have a balanced, skilled team.
The earthing and lightning protection sector has identified the need for professional training to ensure companies can properly resource the industry’s growth. The vehicle for this training is the Lightning Conductor Engineering Apprenticeship run by the Construction Industry Training Board (CITB). Running since the early 1990’s, it continues to deliver quality, professionally trained engineers into the industry.
Omega has grown steadily over recent years and, in order to properly resource growth, has been a strong advocate of industry apprenticeships. We believe this method is the most effective way to guarantee properly trained and skilled workers are available to meet the growth plans of our business and the industry sector overall. With skilled trades people being effectively ‘home grown’ through the apprenticeship scheme, companies are able to ensure a good knowledge of health & safety together with best practice job related skills are developed to the highest standard.
The apprentice route does not come without a need for some crucial added input from the recruiting company.The recruitment and retention process used by Omega follows a professional model:-
Good recruitment practices are the key
Our involvement is vital so we spend time ensuring we recruit the right type of person to fit the role. We have built a good reputation for training and so soliciting interest in our apprenticeship scheme is not difficult.
Selected applicants are interviewed to assess suitability and determine whether they would fit in to the organisation - this is a particularly important factor in ensuring long-term retention. Candidates who successfully negotiate through the first round interviews attend the CITB National Construction College (NCC) at Bircham Newton near Kings Lynn for further suitability assessments. Those passing the rigorous rounds of interviews and assessments are then offered places on the apprenticeship programme and are based at one of five regional offices.

Structured training is essential
Apprentices are recruited in early autumn to provide an introduction to working life, the construction industry and the company before they start their training at NCC.
The academic and off-the-job practical training usually starts in January and comprises 24 weeks residential training at NCC over a two-year period. Off-the-job training covers all technical and practical aspects of the job. The College also provides welfare, sport and other activities which help our apprentices successfully complete their academic training.
Off-the-job training is augmented by on-the-job training. Apprentices are taught in a wide range of disciplines including health and safety, safe accessing, earthing and lightning protection design in order to satisfy evidencing criteria needed for the successful completion of the course.
It is important to celebrate the success of the trainees and this is done internally by updating company notice boards, several other communication methods and by senior managers and directors of the company attending the annual prize giving at NCC.
Ensuring retention
The direct cost of employing an apprentice is roughly £20,000 over the two year period, after the CITB grant. Considering the costs of recruiting and training over the two-year period, our key driver is to ensure appropriate retention policies are in place. These include regular meetings with apprentices, visiting them whilst at the college and working closely with CITB staff. It is important to monitor the progress of apprentices and provide them with support, guidance and encouragement.
Omega’s recruitment plan together with ongoing mentoring means it retains in excess of 90% of all apprentices through to the end of their apprenticeship. More than 13 years after the first lightning conductor engineering apprenticeship course was run, we still have an overall retention of 65% of all the apprentices recruited.
Success of Apprenticeship Training Scheme
As with any business asset, the measure of success is based upon the return on investment. We believe recruiting apprentices is vital to the current and future growth plans of our business. The real success is in ensuring the company has the right number of competent people to fulfil the needs of our customers in a safe, professional and efficient manner. It follows that if the company is able to achieve this aim then it benefits from a more loyal customer base, reduced long-term recruitment costs and a more effective workforce. In the end this whole process aims for and achieves enhanced profitability.
Benefits to Industry
The construction industry, sadly, has a reputation for harbouring many unprofessional operators. Properly recruited and trained apprentices developing into competent trades people will go some way to achieving a reputation for trust and professionalism.
Omega Red Group has heavily supported industry apprenticeship training since the course started 12 years ago. As a result of this investment, almost 100 apprentices over the last 13 years, the company has doubled turnover with a much lower proportional increase in its labour force.
Without investment in apprentices, customers and the industry will suffer from a lack of competent, safe tradespeople. Whilst apprentices involve a short term cost, without them the industry will never achieve the respect, and profitability, it needs.

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PAT scheme and training from NICEIC


To support its national registration scheme for enterprises conducting portable appliance testing (PAT), NICEIC has developed a PAT training course which will provide enterprises with the key competence qualifications required. An NICEIC Guide to Electrical Equipment Maintenance is also available as a reference.
Many deaths and injuries result from poorly maintained electrical equipment and fires started by faulty electrical appliances. Around 1,000 electrical accidents at work are reported to the Health and Safety Executive each year, of these, 30 people die of their injuries.
All electrical equipment should be maintained and checked regularly to ensure it is safe and in good repair. Managers responsible for electrical equipment maintenance should ensure equipment is maintained in a safe condition, information is available to equipment users to ensure safety, safe procedures for inspection and testing are used and records of inspection and testing are maintained.
The NICEIC scheme and register provides companies with a straightforward route to registration, formal recognition of competence to undertake PAT testing services and a reference for purchasers of PAT testing services.
Safety First, a specialist PAT testing company operating in Northern Ireland assisted NICEIC to pilot the scheme. Mervyn Portis, Director, explained: “We are delighted to be recognised by the NICEIC solely for our PAT testing services. We have seen a growing trend in our clients realising the benefits of only using NICEIC contractors to undertake PAT work. Our clients have the added assurance that our standard of work will be continually monitored.”
Existing NICEIC registrants need do nothing further as they will be contacted separately with details of the scheme. NICEIC approved contractors with full approval will automatically meet the scheme requirements for inclusion in the PAT register.