10 Important Precautions When Working On Low Voltage Energized Equipment (photo credit – pacificsource.net)
With Kind Permission of: Edvard Csanyi (Editor-In-Chief & Electrical Engineer at EEP)
For most work, the electrical equipment must be de-energized because there is a high risk of injury to workers if they work on energized equipment. It may be possible to schedule such work outside of normal work hours to limit the inconvenience.
“Sometimes it is not practicable to completely disconnect low-voltage equipment before working on it.”
For example, it may be necessary to have equipment running in order to test it or fine-tune it. In such cases, the work must be performed by workers who are qualified and authorized to do the work. They must follow written safe work procedures.
You should observe the following important precautions when working on energized equipment, but note that these are not a substitute for proper training and written safe work procedures:
1. Think ahead
Assess all of the risks associated with the task. Plan the whole job in advance so that you can take every precaution, including arranging for help in case of paralyzing shock. Consider the use of a pre-job safety meeting to discuss the job with all workers before starting the work.
2. Know the system
Accurate, up-to-date information should be available to those who work on the system. This means that you should know all equipment installed according to the valid documentation (technical specifications, single line diagrams, wiring diagrams, block schemes etc.).
Be careful, sometimes equipment stated in documentation can differ from the one installed on site – due to the replacing of old (damaged) equipment with the new with similar characteristics.
3. Limit the exposure
Have live parts exposed for as little time as necessary. This does not mean that you should work hastily. Be organized so that the job can be done efficiently.
4. Cover exposed live metal
Use insulating barriers or shields to cover live parts. Plexiglas plates can be useful.
5. Cover grounded metalwork
Grounded metal parts should be covered with insulating material as much as possible. Very important.
To read on further and see the further 5 important precautions when working on low voltage energized equipment please visit Electrical Engineering Portal
Example of Slow Motion Arc Flash 100A Disconnect showing the impact of body position in arc flash. In the video, the door comes off in less than 2 cycles showing that Personal Protective Equipment (PPE) isn’t the only thing to consider when it comes to arc flash. Body position at the point of contact is also important.
Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV/MV switchgears and LV high power busbar trunking (<6300A) in power substations, commercial buildings and industry facilities. Professional in AutoCAD programming.
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“30,000 Arc Flash Incidents per year” Source: ISHN
Arc Flash Articles
Thorne & Derrick International would like to thank Pat Mynett for allowing us to publish his series of Arc Flash articles – over the course of these articles we have discussed the definitions, dangers, statistics, causes, prevention and protection against arc flash.
Pat is CEO at HV Training and Consulting Pty Ltd and is a High Voltage Specialist.
ProGARM are the leading UK manufacturer of high quality Arc Flash Clothing, Garments & Workwear – Thorne & Derrick work successfully with them Protecting Lives.
Thorne & Derrick are leading Specialist Distributors & Stockists of LV, MV & HV Cable Installation, Jointing, Substation & Electrical Equipment.
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T&D, CATU Electrical Safety & Arc Flash Protection Specialists for SAP’s, Linesmen, Jointers & Electrical Engineers – Largest UK Stockist
INVITATION
Thorne & Derrick invite you to join LinkedIn’s largest LV-HV Electrical Discussion Group : Low & High Voltage Power, Cabling, Jointing & Electricals. Discussion subjects include cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV. Network, engage and promote your profile, company or products with over 10,000 influencers.
Special thanks to Rebecca Frain CMgr FCMI Tech IOSH (Managing Director – Electrical Safety UK Ltd) for allowing Thorne & Derrick to publish her interview with Jim Phillips regarding the new IEEE 1584 2018 Edition.
What Is IEEE 1584?
IEEE 1584, published by the IEEE Standards Association, is A Guide for Performing Arc-Flash Hazard Calculations.
This guide provides mathematical models for designers and facility operators to apply in determining the arc-flash hazard distance and the incident energyto which workers could be exposed during their work on or near electrical equipment.
By Rebecca Frain
This week I had the opportunity to interview Jim Phillips regarding the new IEEE 1584-2018 Standard and what to expect with some of the new changes. In addition to being Associate Director for Electrical Safety UK and founder of Brainfiler.com, Jim is also Vice-Chair of IEEE 1584 and International Chair of IEC TC 78 – Live Working.
IEEE 1584 – IEEE Guide for Performing Arc Flash Hazard Calculations was first published in 2002 and is the standard that defines the equations and methods used in many of the arc flash software packages used for arc flash risk assessments. The second edition was published towards the end of 2018 and is a real game changer.
RF: A question many of us have is why did it take 16 years to publish the second edition of this standard?
JP: It has been a long journey. The timeline had many phases during this epic project. The first couple of years were spent developing a test plan and raising money from contributors for this enormous (and expensive) project. This was followed by preliminary tests that we call “Scouting Tests” These were used to help define the direction of the entire testing program.
After the preliminary tests, it took several more years for the project team to complete the main arc flash tests and develop the new model. That phase of testing was completed in 2012 and included over 1800 new arc flash tests. Quite an accomplishment. The 2002 edition of the standard was based on around 300 tests.
After the testing and model development phase, the IEEE 1584 working group created a model review task group to review and validate the new model. This took several more years of effort. During that time there was lots of fine tuning to further improve the accuracy. We completed it all in 2016 when it was now time for the formal balloting process. An interesting side note, the new standard passed on the very first ballot – we were all amazed. However, there were also over 1000 comments from the balloters that we had to address. Needless to say, this took some time to resolve. The second edition of this landmark standard was finally published on November 30, 2019
RF: What has changed with the 2018 edition?
JP: (laughs). It’s actually easier to answer the question “What did not change?” The standard still has the same title. With only a few exceptions, just about everything else is very different. This means what you previously knew about the IEEE 1584 standard can be tossed out.
RF: What is the single biggest change?
JP: That one is easy. The introduction of electrode configurations. The 2002 Edition had only two configurations: 1) An arc flash in an enclosure and 2) An arc flash in open air. Both were based on the test electrodes in a vertical configuration.
There are now five different electrode configurations: Vertical electrodes in an enclosure (VCB) and in air (VOA) which are the same as the 2002 standard but we also have horizontal electrodes in an enclosure (HCB) and in air (HOA) and vertical electrodes in an enclosure terminating in an insulating barrier (VCBB). The idea is the new configurations provide greater flexibility for modeling actual equipment.
RF: How does that affect the risk assessment?
JP: Depending on where the arc flash occurs and the type of equipment, the orientation of the electrodes, can affect the trajectory of the plasma and incident energy that reaches the worker. There is some guidance provided in the 2018 Edition of the standard.
RF: I assume there are other big changes?
JP: Yes. There are adjustments for different enclosure sizes. The enclosure size can have quite an effect on the incident energy. If an arc flash occurs in a smaller enclosure, the arc energy is more focused resulting in greater incident energy reaching the worker. If the enclosure is larger, the energy is not as focused and less energy reaches the worker. As a result, the tests included new enclosure sizes and the development of an enclosure size correction factor for the calculations.
RF: Anything else?
JP: The standard now uses interpolation and extrapolation to fine tune the results and provide better accuracy. There is also a new more detailed calculation for determining the minimum arcing current during an arc flash. The past standard simply used a fixed 85 percent value to determine the minimum.
The new equations are much more complex including a thirteenth-degree polynomial with thirteen coefficients that are selected based on the voltage and electrode configuration. (I hope I didn’t scare anyone away with that comment) The good news is the software takes care of the difficult math for us. The list of changes goes on.
RF: How does this all affect the results from previous studies?
JP: I have a series of worksheets that I developed and use to illustrate the calculations and compare with the 2002 edition. Some calculation results are similar to 2002. However, some can be quite different. It has quite a bit to do with the electrode configuration and other factors such as enclosure size.
RF: Does this change way arc rated clothing and PPE is selected?
JP: The overall risk assessment process is the same as before. i.e. Arc rated clothing and PPE are selected with an arc rating sufficient for the calculated incident energy. However, the difference is with the incident energy calculations using IEEE 1584. The calculations and modeling have changed dramatically.
Arc rated protective clothing is based on the standards: IEC 61482-1-1 and IEC 61482-2. There are a few other IEC standards for arc flash protection as well. These standards are from the IEC TC 78 Committee that has a group of highly knowledgeable and talented experts from around the globe all working towards developing and maintaining product standards for greater worker safety.
RF: We are looking forward to hearing more about the 2018 Edition of IEEE 1584 on September 24 at the upcoming International Arc Flash Conference in Manchester.
JP: Thank You Becky! I am looking forward to it. See you soon!
Arc Flash International Conference -Manchester Airport Tuesday 24th September
Company Profile
Electrical Safety UK Ltd
Electrical Safety Management is our core business. We provide expert consultancy and advice for blue chip organisations across Europe concerned with the safe management of risk associated with all electrical work activities. ESUK provide a multi-faceted holistic approach including a full electrical safety management program, project management and policy documentation all bespoke to the client’s requirements including fully accredited and bespoke training courses and personnel assessment programmes.
Here at Electrical Safety UK, our team delivers a range of professional services to customers in a variety of Market sectors. The team prides itself on the quality of the services it delivers to companies at the heart of manufacturing, engineering, energy, food production and education in the UK and Europe.
ESUK Services include:
1 Electrical Safety Management – Specialist consultancy and advice concerned with the safe management of risk associated with all electrical work activities. ESUK offer a multi-faceted approach including a full electrical safety management program, full project management and policy documentation bespoke to a client’s requirements.
2 Electrical System Studies – ESUK are the UK’s foremost exponent of Arc Flash Technology and carry out a wide range of power system studies, including Fault Level Analysis to IEC and ANSI standards, Protection Coordination, and complex Arc Flash Risk Assessments.
3 Training – ESUK offer both accredited and bespoke training courses including City & Guilds, IOSH, Safety Pass Alliance, Energy and Utility Skills. ESUK are also registered with the EEIAS and CIPD for recognition and accreditation of bespoke training courses.
Thorne & Derrick International are specialist distributors of LV, MV & HV Cable Installation, Jointing, Duct Sealing, Substation & Electrical Equipment – servicing UK and global businesses involved in cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.
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Safe Electrical Isolation
Thorne & Derrick International, a Panduit Channel Partner, based in the UK and Specialist Distributors of Electrical Safety Equipment are delighted to provide this following Product Endorsementof Panduit Verisafe by Craig O’Neill of Steve Willis Training Ltd.
Initially sceptic but nevertheless open-minded Craig wanted to learn more – so we arranged a product demonstration.
” Verisafe is an electrical safety product manufactured by Panduit that automatically isolates electrical control panels and distribution boards.The risk of arc flash is an incredibly dangerous problem – arc flash incidents and blasts can vaporise someone in a split second. Having worked in substations for the early part of my career I was always terrified of being responsible for electrical isolation. One false move and it’s too late.” comments Craig.
“Verisafe eliminates 99.999% of this risk and should be implemented to every panel as a first step to isolation procedures. My concerns initially was the device picking up inductive back emf and other induced currents but the demonstration carried out by Glen Bate (Panduit IEI Account Manager) proved it can detect these.”
“Verisafe even detects when a phase has lost connection!”
“I am very good at finding product faults or shortcomings but so far I’ve found none.”
“The electrical safety device needs maintenance like any product but if put in a professional environment, this could easily be implemented into regular checks. Safe electrical isolation is a lesson we drum into our learners at Steve Willis Training Ltd because high standards of professionalism is at the heart of what we do. Electrical safety is at the forefront of being a professional and so it fits right in with our ethics and we were very pleased to have Glen Bate visit and discuss it with us. The students really had a good think about safe isolation after he left and it really helped move the us up a peg on the professional ladder.”
SWT Specialists In Building Engineering Services Training
Who Are Steve Willis Training Limited?
We are specialists in building engineering services training with over 18 years’ experience at our first class training centres in Burgess Hill, West Sussex and Portchester, near Portsmouth. Our training ranges from short courses for tradespeople to full apprenticeships and retraining for those leaving the armed services.
We treat you as an individual, finding the perfect course to suit your needs based on your requirements, experience and qualifications – we’ll never sell you a course you don’t need. We have an excellent reputation – most of our business comes from repeat customers and personal recommendation – and we are approved by all the industry bodies.
We are proud to be an EU Skills approved centre for our IGEM/IG/1 compliant gas managed learning programme, City & Guilds approved for our electrical training, and an OFTEC approved oil training centre.
Steve Willis Training Ltd
Unit F2, Sheddingdean Industrial Estate
Marchants Way, Burgess Hill
West Sussex, RH15 8QY
— SteveWillisTraining (@Steve_WillisLTD) June 12, 2019
Thorne & Derrick
T&D are Specialist Distributors to UK Distribution Network Operators (DNO’s), NERS Registered Service Providers, ICP’s and HV Jointing Contractors of an extensive range of LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt– this includes 11kV/33kV/66kV joints, terminations and connectors for both DNO and private network applications.
Contact our UK Power Team for competitive quotations, fast delivery from stock and technical support or training on all LV-HV products.
Arc Flash Inflicts Serious Electrical Burns- HSE Image Of Accident Scene
By Grant Prior for Construction Enquirer
Construction Enquirer is an online only magazine focusing on the latest news stories, contract opportunities and job vacancies – Completely Free.
Arc Flash
Two companies have been fined after a worker received serious electrical burns caused by an arc flash during demolition work.
Chelmsford Magistrates Court heard how on April 12 2017, two demolition workers employed by sub-contractor R B Haigh & Sons were removing electrical distribution equipment from a switchgear room at the former Molecular Products site in Thaxted, Essex.
Alan Banks had been told by the principal contractor that the electrical equipment had been isolated. To reassure his colleague that it was safe he threw a crowbar at the 400V ac equipment.
This came into contact with live exposed wires, causing a flashover and temperatures of several thousand degrees, followed by a subsequent fire.
As a result Banks suffered serious burn injuries and was immediately hospitalised.
An HSE investigation found that the task being undertaken had not been properly planned and suitable control measures were not implemented to ensure the isolation of the electrical power supply.
The principal contractor, A J Wadhams & Co Ltd failed to follow the clear procedures outlined in their risk assessments and method statements, which identified all equipment must be treated as live unless written authorisation proved otherwise.
Russell Haigh and Stuart Haigh (Partners of R B Haighs & Sons) of Thaxted, Essex, pleaded guilty to safety breaches and were fined £80,000 and ordered to pay costs of £3882.65.
AJ Wadhams & Co Limited trading as Wadham Homes of London also pleaded guilty to safety breaches and was fined £80,000 and ordered to pay costs of £3816.60.
After the hearing HSE inspector Adam Hills said “This incident has had a significant impact on Mr Banks life and the injuries could so very easily have been fatal.
“Had the companies followed the control measures outlined in their respective risk assessments, then this incident would not have occurred.
“Never assume that an electrical supply is disconnected. Always check with the Distribution Network Operator or a qualified electrician to obtain written proof of isolation before commencing work.”
ARC FLASH STATISTICS
30,000 Arc flash incidents per year
7,000 Burn injuries per year
2,000 Hospitalisations per year
400 Fatalities per year
“30,000 Arc Flash Incidents per year” Source: ISHN
How To Protect Yourself Against Arc Flash
Arc flash protection is provided by specialist clothing and garments for “head-to-toe” protection – everything from arc flash coveralls to arc flash trousers.
Enhanced and effective arc flash protection is safely achieved by wearing layers of protective clothing and garments manufactured from inherent fibres and which feature specific Arc Flash resilient components. Without the correct high-quality garments, arc protection levels will be compromised.
centres in Burgess Hill, West Sussex and Portchester, near Portsmouth. Our training ranges from short courses for tradespeople to full apprenticeships and retraining for those leaving the armed services.
