Chris Ross explains the principle themes to the Arc Flash Protection Programme from J & K  Ross

Electric arc is one of the most deadly and least understood hazards of electricity. The outcome of an arc flash can be disastrous but most people are unsure how to deal with the risks effectively.

An electric arc is an ongoing plasma discharge through normally non-conductive media such as air and occurs when there is a short circuit through the air between conductors or conductors and the ground, resulting in hazards including exposure of workers in front of the electric arc to extremely high temperatures, ultra violet light, toxic smoke and fumes and fast moving debris. This can result in burns, blindness, lung damage, hearing damage and death to not only the people working on the electrical equipment but also to people located nearby. J & K Ross has developed the Arc Flash Protection Programme to help companies assess the potential risks of arc flash, carry out the necessary checks and implement improved procedures if necessary. This may include the implementation of personal protective equipment (PPE).

Risk Assess
People working in the vicinity of or at energised parts of electrical systems need to be protected against the effects of possible electric arcing. All such work needs, first of all, to be subjected to a risk assessment. This will enable the risk from arc flash to be identified, determine who might be harmed and form the foundation of the next steps.

The severity of the thermal effect of an arc flash is defined as incident energy, which may arrive at the worker at a given distance from the electric arc, and is measured in calories/centrementre² (cal/cm²); it is the energy that a victim, at a given distance from the electric arc, could receive to the surface of their clothing. In cases where the clothing is not sufficiently protective against the heat and radiation generated by an electric arc, the victim may suffer serious skin burns. An arc flash study will tell you the incident energy likely to occur due to the flashover, or in simple terms - how big is the bang? Following a risk assessment it may be necessary to carry out an arc flash study to establish the potential incident energy and then suitable risk control measures can be explored. Most importantly, there will be an evaluation that will highlight the cases of low risk, those which will need other protective measures and those areas where there is a great danger to workers who engage in live working activities or are working on or close to energized electrical equipment.

Based on the outcome of the risk assessment and arc flash study, control measures need to be implemented to remove, eliminate or reduce the risk. These measures should adhere to the following hierarchy of risk controls:
1. Elimination- de-energise equipment before beginning work
2. Minimisation - investigate trip times or fuse ratings and explore possibilities for faster disconnection times.
3. Information and training - educate workers to ensure their competence
4. Control the risk - properly maintain equipment and substations to ensure safe working systems
5. PPE - issue as a last line of defence to help prevent burn injury to workers

If it is still necessary to protect workers, providing all other practicable measures have been taken to minimise the risk, adequate PPE should be issued as a last line of defence. PPE can help protect against the thermal effects of an arc flash but it doesn't prevent the accident from happening in the first place.

Flame resistant (FR) clothing can be rated based on its Arc Thermal Performance Value (ATPV) in cal/cm2. To properly protect a worker, the ATPV rating of the FR clothing must exceed the calculated prospective incident energy caused by an arc flash onto the worker at a given distance from the electric arc. J & K Ross, in conjunction with DuPont Personal Protection, has developed ARCBAN® a range of CE certified arc flash protective garments made from Nomex®. The ARCBAN® range of garments are designed to be layered to offer the relevant level of protection when required for different jobs with different possible incident energies and ensure that the worker is not restricted or compromised with cumbersome clothing, which would have been selected based on being appropriate for the worst case situation. Layering the garments can help to increase the ATPV levels due to the air gaps in between the garment layers.  It can also help with matching the hazard and risk with the appropriately designed PPE resulting in the wearer having more fit for purpose and comfortable solutions for the relevant hazardous environment.

The ARCBAN® range incorporates DuPontTM Nomex®, an inherently flame resistant meta-aramid fibre that does not melt, drip or support combustion in the air.  The thermal behaviour of Nomex® is due to its molecular structure and not by applying a flame retardant chemical substance to the fabric, yarn, fibre or polymer. This means that Nomex® offers permanent protection that cannot be washed or worn away.  The ARCBAN® range offers head to toe solutions providing various levels of electric arc protection.

DuPontTM and Nomex® are registered trademarks or trademarks of E.I. du Pont de Nemours and Company or its affiliates.ARCBAN® is a registered trademark of J & K Ross.

call 01925 645645

From a Craftman's workshop to a modern industrial company

In our great-grandparents' time electricity was by no means a matter of course. At the beginning of the 20th century, electricity was at best available in large cities but rarely in rural areas. It was only at the beginning of the 1920's that electricity was made accessible to many small towns and villages for the first time.

The history of DEHN's success started in Nuremberg on January the 21st in 1910, when Hans Dehn founded his electrical installation company. Very soon he was involved in the complex problems of lightning protection. By 1918 he had published his first patent on this subject and started the production of lightning protection components. It is through Hans Dehn's entrepreneurship and vision that has seen DEHN become a world leader in this field.

Located in Neumarkt/Oberpfalz, DEHN is a third generation, worldwide family owned enterprise, employing more than 1000 people in Neumarkt and has seen almost 2000 young people trained over the last 100 years. The wide range of products now includes more than 4000 components and devices, specialising in three product ranges, lightning protection, surge protection and safety equipment. Recent products such as the DEHNventil, DEHNguard, Blitzductor and HVI conductor are milestones in the development of class leading lightning and surge protection and further proof of the talent within in the company.

As well as providing innovative products for lightning and surge protection, DEHN provides specifically designed protection concepts as well as engineering and test performance in the company's impulse current laboratory.

Our founder's ideas, continuous intensive research and development effort, combined with high social competence concerning its employees, has made DEHN a global market leader and pioneer in its field. Together with key principles of quality, innovation, customer satisfaction and confidence, ensures that human and engineering safety is always DEHN's uppermost priority.

To help celebrate the DEHN Groups 100 year anniversary, DEHN (UK) has expanded its nationwide seminars on BS EN 62305, the current Lightning and Surge Protection Standard. Released a new UK Lightning Protection Catalogue containing the most popular products from the UK and Europe and you will find DEHN (UK) exhibiting at Electrex in June and the M&E show in October, for more information on these and much more visit our website

Everyone at DEHN (UK) would like to thank you for your custom and look forward to working with you in the year ahead to make 2010 a year of real success.

Electrical equipment manufactured for the EU is designed to operate with an incoming supply of between 207V and 253V, which means electrical equipment has to accept a range of input voltages about its nominal design centre. But if the actual supply is higher than the necessary minimum the equipment will often consume excess power. For example, a resistive load subjected to a 5% overvoltage will consume 10.25% more power than necessary.  This excess consumption reduces equipment lifespan and increases ownership costs.

This is the story of a remarkable product manufactured by a similarly remarkable family-run power engineering company, and how it has made significant inroads into the supply transformer market. From technology to market in under two years the Wilson e2 is now specified by leading commercial organisations and blue chip companies.

Leeds based Wilson Power Solutions (WPS) is proud to celebrate the success of its e2transformer range - the UK’s most energy efficient distribution transformer. This is the UK’s first and only super low loss amorphous distribution transformer that substantially reduces operating costs and CO2 emissions. As a result the e2 is already delivering significant energy savings to businesses committed to driving down their energy costs and radically improving their carbon footprint.

The Wilson e2 - the highly efficient transformer brand

The unique e2 is the result of pioneering technology from WPS, a company that is wholly committed to engineering excellence, product innovation and the provision of cost efficient power solutions aimed at reducing environmental impact. The cause for celebration at WPS is that the e2 is a ‘home-grown’ product borne from the collaboration of a small R&D team with an equally small R&D budget at its disposal! Using proven technology and design the Wilson e2 transformers combine amorphous metal cores with low resistance copper conductors to provide unrivalled savings in both core and copper losses.

Groundbreaking Energy Savings -Reducing operating costs by up to 15%

Since its launch just two years ago the Wilson e2 has been able to demonstrate startling
payback results on the initial investment required. The e2 provides guaranteed savings through reduced transformer losses. These savings can be accurately forecast depending on the size of the unit and typical load. For example a 1000kVA transformer at 70% load will save 28,000 kWh (~£2250) per year through loss savings and achieve payback on the additional investment in just 2.5 years. Significant additional savings can be achieved through in-built Voltage optimization capabilities where site supply Voltage is high and Voltage dependent loads are present.

Corporate endorsement
The Wilson e2 transformer is helping numerous customers including NHS hospital trusts such as Whipps Cross University Hospital, the Natural History Museum and leading supermarkets, to reduce their operating costs and lower their carbon emissions. ASDA and Tesco have already recognised the very considerable benefits that Wilson e2 transformers are delivering to their bottom line.

Daniel Travers from the Tesco Corporate Purchasing team commented: “Tesco is installing the Wilson e2 transformer into its estate as we believe it will assist us to improve our emissions target whilst helping us achieve our commercial constraints. The team at Wilson Power Solutions have shown strong technical expertise and customer service.”

The smart Voltage Optimisation solution for HV applications
11-14% kWh reduction

An additional -5% to +7.5% tapping range is built into the Wilson e2 at no extra cost. This enables the operating company to optimise voltage supply from 415V to 380V according to the needs of an individual site, wherever the incoming supply is at medium voltage. This solution avoids the need to invest in supplementary downstream voltage optimisation equipment and represents an extremely cost effective VO for HV installations with a typical reduction of 12% in kWh consumption. The transformer also integrates smoothly with current installations without the risk of disruption. Endorsing the VO capabilities of e2 for additional savings, the Hilton Hotel in Portsmouth saw a significant kWh reduction of up to 14% after replacing their transformer. Similarly, food manufacturer Cranswick bacon recorded an 11% reduction despite increased production levels.

Key features
Lowest combined transformer losses
Built to IEC76/BSEN60076 standard
Interchangeable with most existing installations
Flange heights to EA35-1
Midel or oil filled
Available for ratings from 315kVA- 3MVA
In-built Voltage Optimisation capabilities
Eligible for an interest free Energy Efficiency loan from Carbon Trust

New – the Wilson e2 plus
The new Wilson e2 plus is currently undergoing final trials and is being introduced to provide an ‘intelligent’ Voltage regulation solution where supply to site fluctuates or a constant (+/- 1.25%) output Voltage is required. e2 plus comes with an automatic voltage regulator that operates on load tap changers to provide stabilised site voltage.

Wilson Power Solutions family business

• Wilson Power Solutions is the Yorkshire-based home of family owned businesses, Power and Distribution Transformers Ltd and Richard Wilson Dencol Ltd.

• Now under the direction of the third generation of a remarkable power engineering family, this privately owned group strives to meet and exceed the highest standards of quality, client care, environmental sustainability and social responsibility.  It has a successful and growing export division.

• Passionate about the environment, Wilson Power Solutions is the first UK power engineering company to be certified Carbon Neutral in 2008.

• Leading provider of energy efficient and sustainable power distribution products and solutions:
- Wilson VO – Voltage optimisation equipment for LV applications
- Chargetec battery chargers
- Power and distribution transformers up to 150MVA
- Wilson sustainable: Re-engineered transformers and switchgear
- Buyback of redundant transformers

To share in the cost savings and environmental benefits delivered by e2 contact Wilson Power Solutions for an assessment of your company’s energy management strategy, by calling the Sales Engineering team on

+44 (0)113 271 7588
For more information about products and services visit

Power transformers are a critical, capital-intensive asset for the utility industry.  As an asset manager reviewing the life expectancy of a transformer, or a substation operator responsible for determining the loading capabilities of a transformer, you should be concerned with the water content in your transformer.

One of the most important ageing indicators of transformers is the water content in the solid part of the insulation (paper, pressboard).  Accurate diagnostic tools for determining the health of your transformers is critical. The OMICRON DIRANA is a unique and efficient device which determines the water content in the solid insulation.

Moisture entering in to oil-paper insulation can cause three dangerous effects in transformers: it decreases the dielectric withstand strength, accelerates cellulose ageing (de-polymerization) and causes the emission of gas bubbles at high temperatures.

Water in transformers comes from four sources: residual water after drying, water from cellulose and oil ageing, water through leaky seals or repairs, and water due to breathing.  Therefore, even in the case of a non-breathing transformer the moisture can reach a critical level.

The DIRANA measures the dielectric response of solid insulation in equipment. The dielectric response is a unique characteristic of the particular insulation system.  The increased moisture content of the insulation results in a changed dielectric model and, consequently a changed dielectric response.  By measuring the dielectric response of the equipment in a wide frequency range, the moisture content can be assessed and the insulation condition diagnosed.  For the dielectric response, the measurement is performed as a traditional ungrounded specimen test (UST), made from the high voltage winding to the low voltage winding (CHL) in a two winding transformer.  We are most concerned with the CHL test, as this is the measurement which contains the most cellulose insulation material.  The test connections and modes are the same as used in a traditional transformer insulation Tangent Delta (or power fact)test with the difference being that it is performed at a low voltage, up to 200vpp, and the test is performed at frequencies from 1 kHz to 10µHz. 

The unit combines the polarization current measurement (PDC) method in time domain with frequency domain spectroscopy (FDS) and thus significantly reduces the testing time compared to existing techniques.  Essentially, time domain measurements can be accomplished in a short time period but are limited to low frequencies. The extended measurement range of 5 kHz down to 50 µHz, allows the DIRANA to discriminate between the oil, insulation geometry and paper.  The result is independent from the moisture equilibrium.

The patented technique combines the advantages of both principles.  It acquires data in the time domain from 10 µHz to 0.1 Hz and in the frequency domain from 0.1 Hz to 5 kHz.  This reduces the measuring duration by up to 75% compared to exclusive frequency domain measurements.

DIRANA's moisture determination is based on a comparison of the transformer's dielectric response to a modelled dielectric response. A fitted algorithm compares the measured data with the modelled data and calculates the geometry data, the moisture content, as well as the oil conductivity.  The moisture assessment is based on IEC 60422. The software is very easy to use, and the user only needs to enter the oil temperature.

Aged transformer oils often have increased values of conductivity due to acids and other ageing byproducts. This can lead to incorrect water content results. The insulation model in the DIRANA's software compensates for this influence.

Excessive water content can be extremely detrimental to the life expectancy of a transformer. The Dirana provides a simple, non-intrusive method of detecting this moisture and alerting the user of the need to take action to alleviate the problem.

Tel: 01785 251 000

The use of connectors in wind turbines faces a unique set of challenges explains Kevin Canham of Harting

Working with wind turbines, ambient conditions such as vibration and air humidity are harsher than in some industrial environments. This applies in particular to wind farms sited in offshore waters – an increasingly important location.

As well as needing to be resistant to these environmental influences, it is important prefabricated components can be assembled quickly and without mistakes on-site. One of the requirements is the time taken to assemble these turbines and take them into operation is kept as short as possible.

Application sectors
Fig.1 shows the key areas where high-quality interconnection is required in a wind turbine:
Pitch control: Almost all modern wind turbines use so-called ‘pitch control’ to regulate speed and power output. Here, the angle between the rotor blades and the wind is changed by rotating them around their longitudinal axis. In this application, components in Harting’s flexible Han-Modular‚ connector series can be freely combined, so that users can configure their own connector. An extensive range of modules is available for electric, optical and gaseous signals.

Arcing faults can be quickly detected and cleared using the Falcon Arc Detection System from CEE Relays. Clearing arcing faults more quickly reduces the incident energy of the fault. The incident energy at each busbar and required personal protective equipment (PPE) can be calculated using the Arc Flash Evaluation module of the Power*Tools for Windows (PTW) power system analysis software, helping engineers modify protection settings and the network configuration to reduce the incident energy. Reducing the incident energy reduces the risk to personnel and the expensive downtime due to the damage caused by arcing faults.

Newly announced by APC by Schneider Electric, a global leader in integrated critical power and cooling services, the MGE Galaxy 300 UPS system provides a compact, simplified and reliable solution for protecting small and medium businesses, commercial buildings and technical facilities.  It offers reliable power protection and a robust and easy to install system at the best price to performance ratio.

The new 3-phase UPS is a high availability solution which provides a wide input voltage range for harsh electrical environments; on-line double conversion topology for true isolation between input and output with zero transfer time; parallel capability to increase system redundancy and dual mains feed input for installation of one or two independent power sources.

Riello UPS is proud to protect Sudlows' award-winning data centre with its Multi Sentry Uninterruptible Power Supply system.

Last month the North West based data centre specialist scooped the prestigious Data Centre Solutions' Innovative Data Centre Project of the Year Award 2011 in recognition of Sudlows' unique Data Centre Innovation Pod (DCiP) - one of the most pioneering micro data centre facilities in the UK.

Sudlows has designed and built a fully functional data centre to demonstrate its expertise to both current and potential clients. The 1,000 sq ft facility, costing almost £500,000, was completed back in 2010, and with it, Sudlows has claimed a place as a centre of excellence in the field of data centre design and solutions.

But integral to any successful data centre is the highest quality power protection, and this is where Riello UPS, one of Sudlows' key suppliers, enters the picture.
Sudlows is renowned for advising its clients on the latest in energy and money saving technologies, so with this in mind the company approached Riello UPS to contribute to the project.

Robin Koffler, general manager of Riello UPS (UK), said: "Riello UPS worked closely with Sudlows to organise the many aspects of the UPS installation, commissioning and testing; selecting the100kVA Multi Sentry UPS to illustrate to Sudlows' clients the typical footprint of a UPS.
"The system provides eight minutes of protection when at full load. With Sudlows' usual power requirements using only 20%, the Multi Plus would protect the business for 40 minutes.
"With a continuous supply of conditioned, reliable power ensured by the Riello UPS Multi Sentry, this fully working showroom allows Sudlows' clients to experience state-of-the-art product application and innovation in a functioning data room packed full of the latest technology."
He added: "Riello UPS is pleased to be able to offer an extensive line of environmentally-friendly, energy efficient products that not only meet the most challenging demands of the data centre environment, but also meet the scalability requirements of this growing business sector."

Andy Hirst, projects director for Sudlows, said: "The UPS in a data centre is a critical requirement and one of, if not the most important pieces of kit. "Riello UPS is one of our key preferred suppliers and we have total confidence in their products and services.

"We've always had total support from them throughout all our projects and this is very refreshing. When it comes to UPS products and services, Riello UPS is unbeatable.

"We work with many contractors and suppliers and we are renowned for our quality projects and services. We have to ensure that we work with the best as our reputation in on the line.

"This is why you will see Riello UPS units in the majority of our projects."

The Sudlows and other Riello UPS power protection case studies can be downloaded from the company's dedicated PR website at

To request a free site survey, book a UPS health check or request a quotation call 0800 269 394.
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

ABB's UniGear 500R compact medium voltage switchgear with removable circuit breaker offers the highest levels of safety and reliability combined with simplicity of installation and ease of use for a wide variety of primary distribution applications

This project involved the construction of Europe's largest in-town retail development on a 40 acre site grouping 150,000m2 of shops and leisure complex. Located adjacent to the A40 main western access route to the capital, the contract was awarded to the Australian developer Westfield in 2005 with the work being completed in 2008 at a cost of £1.6 bn

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