Arc Flash Protection
Arc Flash Study: Is It A Legal Requirement?
September 20th, 2019
Andrew Linley, Compliance Director at Electrical Safety UK Limited
The following article about the need to carry out an Arc Flash Study has been produced by Andrew Linley, Compliance Director at Electrical Safety UK Limited. Special thanks for the permission to re-publish your article.
Andrew has vast experience in electrical installation, maintenance and the requirements and the practicalities of electrical inspection, testing and certification. At Electrical Safety UK Limited, they provide expert consultancy and advice for organisations across Europe concerned with the safe management of risk associated with all electrical work activities.
Is arc flash study a legal requirement?
The simple answer is yes…
An arc flash study needs to be carried out by an electrical safety expert, to determine hazards and risks in electrical systems. The need to carry out a suitable and sufficient risk assessment, and to put measures in place to protect those who could be put at risk, is mandated by the following regulations:
- Regulation 4(1) – the Electricity at Work Regulations 1989
- Regulation 3(1) – the Management of Health and Safety at Work Regulations 1999
Regulations
Regulation 4(1) of the Electricity at Work Regulations 1989 states ‘All systems shall at all times be of such construction as to prevent, so far as is reasonably practicable, danger’.
Regulation 2(1) of the same regulations defines danger as meaning the risk of injury and ‘injury means the death or personal injury from electric shock, electric burn, electrical explosion or arcing, or from fire or explosion initiated by electrical energy, where any such death or injury is associated with the generation, provision, transmission, transformation, rectification, conversion, conduction, distribution, control, storage, measurement or use of electrical energy’.
Electricity poses arc flash hazards, and the risks posed are electric shock, burns, fires, arcing and explosion.
We demonstrate the need for Arc Flash Study and Arc Flash Protection
Regulation 3(1) of the Management of Health and Safety at Work Regulations 1999 states ‘every employer shall make suitable and sufficient assessment of (a) the risks to the health and safety of his employees to which they are exposed whilst they are at work; and (b) the risks to the health and safety of persons not in his employment arising out of or in connection with the conduct by him of his undertaking, for the purpose of identifying the measures he needs to take to comply with the requirements of and prohibitions imposed upon him by or under the relevant statutory provisions and by Part II of the Fire Precautions (Workplace) Regulations 1997’.
Conducting arc flash studies
It has been established that we need to conduct arc flash studies of the workplace to determine risks and hazards, but how exactly are they conducted?
The on-site evaluation results in fault current and coordination analysis, fault equipment labelling, recommendations for improvements and requirements for PPE (Personal Protective Equipment). An arc flash study can be carried out by several organisations, including Electrical Safety Uk Ltd.
Further reading
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.
Visit Website: https://www.elecsafety.co.uk/
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 is 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.
Contact Details
Electrical Safety (UK) Limited
2 Genesis Business Park
Sheffield Road
Rotherham
S60 1DX
Tel: 0800 652 1124
Tel: 01709 961 666
Email: [email protected]
Thorne & Derrick
Thorne & Derrick are national distributors of LV, MV & HV Cable Installation, Jointing, Substation & Electrical Equipment – servicing businesses involved in cabling, jointing, substation, earthing, overhead line and electrical construction at LV, 11kV, 33kV, 66kV and EHV. Supplying a complete range of power cable accessories to support the installation and maintenance of low/medium and high voltage power systems:
- Slip-on Cable Terminations
- Cold-shrink Cable Terminations
- Heat-shrink Cable Terminations
- Cable Joints – Heat & Cold-shrink
- Separable Connectors (Euromold)
- Surge Arresters & Switchgear/Transformer Bushings
Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MVÂ
Arc Flash Learning & Resources
Thorne and Derrick are proud to be distributors of ProGARM arc flash coveralls and protection.
We can help – should you require arc flash calculators or advice on the type of clothing and protection available please do not hesitate to contact us.
Arc Flash – The Electrician’s Insidious Companion
July 31st, 2019
Arc Flash – The Electrician’s Insidious Companion Image: Safety Management Services, Inc.
Arc Flash
-
Blog Written By Patrick Mynett -
CEO / High Voltage Specialist at HV Training and Consulting Pty Ltd
Thorne & Derrick International would like to thank Pat Mynett for allowing us to publish his article Arc Flash – The Electrician’s Insidious Companion.
Pat is CEO at HV Training and Consulting Pty Ltd and is a High Voltage Specialist.
In 2014, Pat Mynett decided there was room in the market for another RTO to provide quality electrical training. Especially from a person with recent industry experience, whose main interest was in the electrical safety of workers and the welfare of the plant. Arc flash safety training was a glaring omission in the industry so he developed, wrote and registered a nationally accredited arc flash course for those who work in an arc flash hazard zone.
This is Part 2 in a series of 3 articles about the dangers of arc flash – over the course of these articles we have discussed the definitions, dangers, statistics, causes, prevention and protection against arc flash.
- Introduction to Arc Flash
- Arc Flash – The Electrician’s Insidious Companion
- Overcoming Arc Flash Hazards
The Electrician’s Insidious Companion
Your insidious companion is always lurking there in the background, looking to pounce on people who take short cuts, ignore rules or do not understand how to ban him from the worksite. If your insidious companion pays you a visit you may receive serious burns or pass on to the next world. Do not let this happen to you.
What is an uncontrolled Arc Flash?
A type of electrical explosion that results from a low-impedance (Short Circuit) connection to earth or another voltage phase in an electrical system.
It is the light and heat produced from an electrical arc supplied with Sufficient Electrical Energy to cause fatalities, serious injury, substantial damage, fire, or worse.
What is Sufficient Electrical Energy
In rough figures, a 125kVA transformer 400V (LV) supply would have a fault current capacity of over 3600amps. This just gives an illustration of the current available at the transformer LV terminals.
At the main switchboard this could have dropped considerably, depending on the impedance of the mains, but will always significantly exceed the switchboard load rating.
Padmount transformers can be 20 times the capacity of the above example.
Severity of an arc flash
The severity of an arc flash depends on the amount of fault current available and the duration (Time) the fault is on the system. The system’s voltage is only significant at LV where the volt drop across the arc can be up to 60% of the Low Voltage, so it appears to the protection as a high impedance fault, which therefore clears slowly.
This delay may mean the difference between serious and fatal burns. The careless worker is therefore completely dependent on the distance from and size of, the feeding transformer and most importantly, the switchboard and protection design, commissioning and ongoing maintenance (including tripping batteries) being done correctly.
Overcoming Arc Flash Hazards
Energy received from an arc flash
The energy produced by an arc flash and the energy received from an arc flash are two different things. The energy received from an arc flash is measured in Incident Energy (cal/cm2) depends on the distance from the arc flash. The further you are away from the arc flash source the less the incident energy.
What events can cause an arc flash?
An arc flash initiated when the system is static, no movement of system devices. These events can be caused through vermin (rats, mice, etc.) and hot joints. These events generally occur without injury to personnel as no work is being carried out in the vicinity. However, these events can and do cause significant damage to equipment.
An arc flash initiated when there is movement in the system.
The movements can be;
- working live,
- operator error,
- closing, opening and racking of circuit breakers,
- operating switches/isolators live,
- inappropriate operation of switchgear,
- trying to operate damaged switchgear,
- dropping tool/ equipment on live conductors/busbars,
- circumventing interlocks etc.
When arc flash events are due to movement, fatalities or significant injuries can occur, as well as major damage to equipment.
What can you do to protect against an arc flash incident?
- Do not take short cuts!
- Do not work live!
- Do not operate faulty equipment!
- Get an understanding of arc flash, its causes, its hazards and how to mitigate the hazards!
- Know when it is not safe to proceed with the work!
- Know the correct PPE to select and wear!
- Get training in arc flash hazards and mitigation!
arrow: Protecting Cable Jointers & Electrical Engineers When Working Live On Cables & Switchgear – comprehensive ranges of insulating matting and insulated tools.
Training to recognise Arc Flash Hazards
Now there is training available for people who work at the coal face and operate electrical equipment. This arc flash training imparts the knowledge to recognise, risk assess, mitigate, select the correct PPE for arc flash hazards and know when it is not safe to proceed with the work.
Arc Flash | Jackets | Coveralls | Trousers | Sweatshirts | Helmets | Gloves ProGARM
Selecting appropriate PPE
Wearing the correct type of PPE when working in an arc flash environment is imperative. If an arc flash occurs, without PPE you may not go home for a long time or you may not go home at all.
 ➡ Further Reading
- Arc Flash Clothing & Protection For Safe Windfarm & Wind Turbine Working
- Arc Flash Clothing – PPE To Protect Highways, Street Lighting & Utility Contractors
- Eliminate Arc Flash To Minimise Downtime & Repair Costs At The Circuit Breaker
- Do Insulating Gloves Provide Arc Flash Protection?
- Can Arc Flash Clothing Save Utility Workers Lives?
- Electrical Safety – Arc Flash Accidents & Electrocution In LV-HV Installations
- Arc Flash Calculation – Selecting Clothing & PPE To Protect Lives Against Arc Hazard
THORNE & DERRICK SPECIALIST ELECTRICAL DISTRIBUTOR
LVÂ ♦ MVÂ ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
- Key Products: MV-HV Cable Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Cable Jointing Tools, Feeder Pillars, Cable Ducting, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.
- Distributors for: 3M, ABB, Alroc, Band-It, Catu, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, Prysmian, Roxtec.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
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.
Arc Flash Learning & Resources
Thorne and Derrick are proud to be distributors of ProGARM arc flash coveralls and protection.
We can help – should you require arc flash calculators or advice on the type of clothing and protection available please do not hesitate to contact us.
Introduction To Arc Flash
July 31st, 2019
“30,000 Arc Flash Incidents per year” Source: ISHN
Arc Flash
-
Blog Written By Patrick Mynett -
CEO / High Voltage Specialist at HV Training and Consulting Pty Ltd
Thorne & Derrick International would like to thank Pat Mynett for allowing us to publish his article Introduction To Arc Flash.
Pat is CEO at HV Training and Consulting Pty Ltd and is a High Voltage Specialist.
In 2014, Pat Mynett decided there was room in the market for another RTO to provide quality electrical training. Especially from a person with recent industry experience, whose main interest was in the electrical safety of workers and the welfare of the plant. Arc flash safety training was a glaring omission in the industry so he developed, wrote and registered a nationally accredited arc flash course for those who work in an arc flash hazard zone.
This is Part 1 in a series of 3 articles about the dangers of arc flash – over the course of these articles we have discussed the definitions, dangers, statistics, causes, prevention and protection against arc flash.
- Introduction To Arc Flash
- Arc Flash – The Electrician’s Insidious Companion
- Overcoming Arc Flash Hazards
What is an Arc Flash?
An electric arc occurs whenever a circuit breaker, switch or isolator (Device) is opened and when there is current is flowing in the circuit. However, most devices under normal operating conditions are designed to control the arc when opening or closing.
An arc flash may occur when the arc is uncontrolled and there is sufficient energy released to cause harm or damage.
Arc flashes occur both at high voltage and at low voltage. There is little discrimination, low voltage arc flashes injuries are just as damaging at high voltage injuries.
An arc flash is the light and heat produced from an electrical arc supplied with sufficient electrical energy to cause substantial damage, harm, fire, or injury.
What is sufficient electrical energy, lets look at two situations, firstly a domestic situation and then a commercial, industrial or mining situation.
A domestic situation:Â In most domestic dwellings, even though the risk of electric shock is present, the risks of an arc flash are only minor, as there is normally insufficient energy to cause a serious arc flash. The main switch / main circuit breaker is normally quite a distance from a transformer. The distance and smaller cables sizes results in much higher circuit impedance and lower fault current.
A commercial, industrial or mining situation:Â This is a different story, as the results of an arc flash can be catastrophic. The main switch / main circuit breakers may be only a few meters from a transformer, fed by busbars or large cables. This results in extremely low impedance and very high fault currents.
What can initiate an Arc Flash?
There are many things that can initiate an arc flash, they can be divided into two groups.
- Group 1: An arc flash when the electrical system is static and
- Group 2: An arc flash when there is movement in the electrical system
Group 1:Â An arc flash can occur and be caused by items such as vermin, hot joints etc. Â In these cases, there can be substantial damage to equipment, but injury to people is extremely rare. Vermin avoid areas when people are around.
Group 2: Â An arc flash can occur and be caused or initiated by items when there is movement in the system, such as closing or opening of circuit breakers, switches or isolators, applying earths, opening enclosures, dropping tools, inappropriate use of tools etc.
This is where the majority of arc flash injuries occur.
Arc flash can be caused by; switching devices being operated that are faulty or damaged, circuit breakers racked when closed, isolators opened on load, applying earths to energised conductors, closing a switch onto an earthed conductor, inadvertent contact through working close to live conductors, dropping tools onto live conductors, drilling into enclosures and the drill contacts an energised conductor.
Many of these causes are due to human error, working live, complacency, lack of training, lack of maintenance, taking short cuts etc.
Who are the people that get hurt
from an Arc Flash?
Nearly all arc flash injuries occur to people in two distinct groups.
Electrical workers and non-electrical workers.
Injuries to electrical workers make up the majority of arc flash injuries. They are the people that generally operate electrical switchgear, work on or close to energised conductors.
Injuries to electrical workers occur due a to lack of understanding, lack of training, complacency and ignoring or short cutting safety rules. There is tremendous pressure on electrical workers to keep electricity supply on when working on or close to energised conductors.
This pressure is applied by people who do not have any understanding of electrical hazards. Legislation in Australia only allows work on or close to energised conductors under strict conditions. Yet many electrical workers still work on or close to energised conductors.
Non- electrical workers who operate industrial switchgear is the other group where arc flash injuries occur.
There are many non-electrical workers in industry that switch industrial electrical low voltage loads on and off.
There are some that operate high voltage switchgear to create an isolation point for non-electrical work. Most of these non-electrical workers would not know what an arc flash is.
How many people get hurt in Australia
through Arc Flash and what can we learn in the UK?
Arc flash injury statistics are hard to acquire and quantify. In many cases this is due to arc flash injuries recorded at electrical injuries.
About three years ago figures were obtained from one Australian state’s hospitals on the number of people admitted with serious electrical (arc flash) burns. When these figures are extrapolated out to cover all of Australia. On average (30) thirty people each year get admitted to hospital with arc flash burns and (1) one fatality occurs every two years.
These figures can be backed up by the fact that in NSW/QLD and WA for the three months ending in November 2018, there was one fatality and 7 people who received serious burns.
In 2014 two fatalities occurred in WA.
It is unfortunate, that many arc flash injuries do not get reported and in some cases the information gets suppressed due to legal reasons.
The UK has 3 times the population of Australia, so it can be reasonably assumed that the numbers of injuries in the UK are 3 times greater.
90 people hospitalised and 1.5 fatalities each year.
What are the costs from an Arc Flash?
There are human costs and financial costs.
Human costs: It is not just the injury, it’s the trauma of recovery (burns take a long time to heal and scar for life), the family trauma (living with someone who is in constant pain and disfigured), loss of income (many burns victims never return to work). The divorce rate of burn victims is extremely high.
Financial costs: Loss of supply can be from an hour to several weeks. A single piece of equipment may only be damaged and easily replaced or a whole switchboard/transformer etc. may be damaged beyond repair. The costs can be from a few dollars up to millions of dollars. I would suspect that arc flash incidents cost Australian industries many millions of dollars each year.
In Conclusion
Arc flash is a real and present hazard.
Yet, it is often ignored or given the pretence to comply by industry.
The majority of electrical workers do not have an understanding of Arc Flash or its hazards, if they did we would not have the number of arc flash injuries that we do have at present. Arc flash training is available, but few companies take it up due to the lack of understanding of the subject.
arrow: Protecting Cable Jointers & Electrical Engineers When Working Live On Cables & Switchgear – comprehensive ranges of insulating matting and insulated tools.
Protect Yourself Against Arc Flash
Arc flash protection is provided by specialist clothing and garments for “head-to-toe” protection.
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.
âž¡ Further Reading
- Arc Flash Clothing & Protection For Safe Windfarm & Wind Turbine Working
- Arc Flash Clothing – PPE To Protect Highways, Street Lighting & Utility Contractors
- Eliminate Arc Flash To Minimise Downtime & Repair Costs At The Circuit Breaker
- Do Insulating Gloves Provide Arc Flash Protection?
- Can Arc Flash Clothing Save Utility Workers Lives?
- Electrical Safety – Arc Flash Accidents & Electrocution In LV-HV Installations
- Arc Flash Calculation – Selecting Clothing & PPE To Protect Lives Against Arc Hazard
THORNE & DERRICK SPECIALIST ELECTRICAL DISTRIBUTOR
LVÂ ♦ MVÂ ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
- Key Products: MV-HV Cable Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Cable Jointing Tools, Feeder Pillars, Cable Ducting, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.
- Distributors for: 3M, ABB, Alroc, Band-It, Catu, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, Prysmian, Roxtec.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
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.
Arc Flash Learning & Resources
Thorne and Derrick are proud to be distributors of ProGARM arc flash coveralls and protection.
We can help – should you require arc flash calculators or advice on the type of clothing and protection available please do not hesitate to contact us.
Overcoming Arc Flash Hazards
July 30th, 2019Overcoming Arc Flash Hazards
Arc Flash Hazards
-
Blog Written By Patrick Mynett -
CEO / High Voltage Specialist at HV Training and Consulting Pty Ltd "Every worker can go home at night after a day at work"
Thorne & Derrick International would like to thank Pat Mynett for allowing us to publish his article Overcoming Arc Flash Hazards.
Pat is CEO at HV Training and Consulting Pty Ltd and is a High Voltage Specialist.
In 2014, Pat Mynett decided there was room in the market for another RTO to provide quality electrical training. Especially from a person with recent industry experience, whose main interest was in the electrical safety of workers and the welfare of the plant. Arc flash safety training was a glaring omission in the industry so he developed, wrote and registered a nationally accredited arc flash course for those who work in an arc flash hazard zone.
This is Part 3 in a series of articles about the dangers of arc flash – over the course of these articles we have discussed the definitions, dangers, statistics, causes, prevention and protection against arc flash.
- Introduction to Arc Flash
- Arc Flash – The Electrician’s Insidious Companion
- Overcoming Arc Flash Hazards
Arc Flash
An arc flash can cause minor injuries, third degree burns and potential death as well as other injuries including blindness, hearing loss, nerve damage and cardiac arrest. Fatal burns can occur when the victim is several feet from the arc. Serious burns are common at a distance of 10 feet – arc flash can generate heat 4 times greater than the surface of the sun.
The Energy In An Uncontrolled Arc Flash
Arc Flash is the result of a breakdown in insulation which in turn causes an excessive flow of current between phase and earth, phase to neural or phase to phase. This current flow may be thousands of amps, that is why arc flash fault current is measured in kilo Amperes (kA).
The energy released from an arc flash is governed by the systems voltage, the generation capacity available, the impedance to the source and the time the fault is on the system.
Arc flash is made up of molten metal, plasma, intense heat, intense light, gas, intense sound, and pressure waves, all released in milliseconds.
Arc Flash Energy In Perspective
To get some idea of the energy that can be released: a 415 volts system with 5000 amps/ 5kA of fault current flowing for 500 milliseconds or 2500 amps/2.5kA flowing for 1 second, it would have a similar energy release as one stick of explosive.
A 200kVA transformer’s fault current at the 415-volt terminals can be up to 6170 amps.
A 100kVA transformer’s fault current at the 415-volt terminals can be up to 3085 amps.
Both having the capacity to produce the energy shown in the paragraph above.
How Is The Energy From An Arc Flash Measured?
Firstly, the energy at the arc flash source, is different from the energy received from an arc flash. It all depends on where you stand. So, the energy received depends on the distance to the arc flash source.
The energy received from the arc flash is called Incident Energy.
It is measured in calories per centimetre squared, (cal/cm2).
Incident Energy is:Â The amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event.
So What Actions Can Initiate An Arc Flash
You will notice that all of the below, are actions that happen very frequently but only a very few ever initiate an arc flash. They are not normally the cause, there is usually other contributing factors,
1: Opening or closing a circuit breaker
2: Racking a circuit breaker in or out (see picture below)
3: Working live
4: Opening or closing a switch
5: Opening or closing an isolator
6: Dropping tools
7: Testing
8: Replacing parts
What Initiates & What Causes An Arc Flash
Are Different In Many Cases
Because the initiating actions, are actions that are all part of normal operations carried out frequently by many electrical workers, very little thought is given to the action itself.
Just as an example:  A circuit has been modified. (AS/NZS 3000 specifies the circuit must be tested before re-energisation) yet many ignore this testing. The circuit breaker is closed without thought and there is a fault with the modification. The closing of the circuit breaker initiates an arc flash at the modification. If the circuit breaker has not been maintained, it may not clear the fault as per the trip settings time, it may not clear the fault at all, or another arc flash may occur at the circuit breaker.
Initiation Causes
1: Closing a circuit breaker – Closing onto a short circuit, the circuit breaker is under rated
2: Racking a circuit breaker in – Racking in a closed-circuit breaker onto a load
3: Closing a switch – Closing onto a short circuit and the upstream protection is incorrect
4: Opening an isolator – Opening an isolator with load on the circuit
5: Dropping tools – Working in a live switchboard with uninsulated tools
6: Testing using a non-rated multimeter with the settings on the wrong function
7: Replacing parts – Long tails make contact with live parts
8: Working live ignoring legislation, such as peer pressure not to turn the supply off
➡ Protecting Cable Jointers & Electrical Engineers When Working Live On Cables & Switchgear – comprehensive ranges of insulating matting and insulated tools.
Causes Can Often Be Traced To Human Performance
Let’s look at some human performance issues.
Not concentrating, “I’ve always done it this way,” rushing to finish the job, taking short cuts, ignoring standard procedures, lack of knowledge etc.
One of the biggest issues with arc flash, is the lack of knowledge. Most electrical workers have heard of arc flash and have some idea of the results but have little understanding of arc flash hazards and mitigation of the hazards.
A few years ago, it was taken as an occupational hazard that electrical workers would occasionally get injured or die from exposure to an arc flash. This should not be the case today as arc flash is now a recognised foreseeable occupational hazard.
Where Do We Stand Under Law?
Australian Health and Safety law is quite specific about occupational hazards.
Australian Model Work Health and Safety Regulations: Chapter 3 General Risk and Workplace Management
34 Duty to identify hazards
A duty holder, in managing risks to health and safety, must identify reasonably foreseeable hazards that could give rise to risks to health and safety.
35 Managing risks to health and safety
A duty holder, in managing risks to health and safety, must:
(a) eliminate risks to health and safety so far as is reasonably practicable; and
(b) if it is not reasonably practicable to eliminate risks to health and safety—minimise those risks so far as is reasonably practicable.
As arc flash is now a foreseeable occupational hazard, so there is a duty to manage these hazards. Yet many companies choose to either ignore or play lip service to arc flash hazards.
Understanding Arc Flash Comes From Quality Training
Training workers is one area where little is happening.
Some large companies consider a familiarisation session of one hour as adequate training.
To cover training adequately takes 5 to 7 hours to cover what is required. Training should include; what arc flash is, Legislation & Standards, definitions, incident energy, causes of arc flash, PPE selection and requirements, arc flash risk management.
Protect Yourself Against Arc Flash
Arc flash protection is provided by specialist clothing and garments for “head-to-toe” protection.
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.
âž¡ Further Reading
- Arc Flash Clothing & Protection For Safe Windfarm & Wind Turbine Working
- Arc Flash Clothing – PPE To Protect Highways, Street Lighting & Utility Contractors
- Eliminate Arc Flash To Minimise Downtime & Repair Costs At The Circuit Breaker
- Do Insulating Gloves Provide Arc Flash Protection?
- Can Arc Flash Clothing Save Utility Workers Lives?
- Electrical Safety – Arc Flash Accidents & Electrocution In LV-HV Installations
- Arc Flash Calculation – Selecting Clothing & PPE To Protect Lives Against Arc Hazard
THORNE & DERRICK SPECIALIST ELECTRICAL DISTRIBUTOR
LVÂ ♦ MVÂ ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
- Key Products: MV-HV Cable Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Cable Jointing Tools, Feeder Pillars, Cable Ducting, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.
- Distributors for: 3M, ABB, Alroc, Band-It, Catu, Cembre, Centriforce, CMP, Elastimold, Ellis Patents, Emtelle, Furse, Lucy Zodion, Nexans Euromold, Pfisterer, Polypipe, Prysmian, Roxtec.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
T&D, CATU Electrical Safety & Arc Flash Protection Specialists for SAP’s, Linesmen, Jointers & Electrical Engineers – Largest UK Stockist
INVITATION
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Arc Flash Learning & Resources
Thorne and Derrick are proud to be distributors of ProGARM arc flash coveralls and protection.
We can help – should you require arc flash calculators or advice on the type of clothing and protection available please do not hesitate to contact us.
Arc Flash Clothing & Protection For Safe Windfarm & Wind Turbine Working
November 22nd, 2018
Arc Flash Clothing & Protection
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uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager
Arc flash
Arc flash accidents are not nearly as rare as you would think and the hazards they create are severe. In wind turbines, these hazards are magnified.Â
Installing and maintaining wind turbines can be a tricky job and it is important to understand the importance of staying safe and Protecting Lives by wearing arc flash clothing including an arc flash helmet, insulating boots and arc flash gloves.
In fact, most employers wouldn’t dream of permitting their teams on site without adequate protection and workers themselves are more than clued up when it comes to the latest electrical safety equipment requirements.
However, the same can’t be said when it comes to the potentially fatal risk posed by an Arc Flash – a relatively misunderstood, but extremely common type of electrical explosion facing those working on onshore or offshore, private or commercial wind turbine projects.
Arc Myth Busted: Did you know most arc flash accidents occur in LV systems?
Especially legacy switchgear and switchboards undergoing the The Three R’s – retrofit, refurbishment or repair. Modern technology Low, Medium & High Voltage Electrical Equipment with integral insulated arc-free busbar assemblies, arc flash relays and arc quenching switchgear, such as manufactured by Eaton, minimises but does not eliminate the risk of arc flash completely.
Of course, the best way to avoid arc flash is to de-energise – nevertheless, Arc Flash can occur on power systems inadvertently made live while undergoing maintenance under planned isolation procedures.
Image: Safety Management Services, Inc.
A Wind Turbine Arc Flash Incident
The Clear & Present Danger
Although no injuries were reported – thankfully – the devastation inflicted to the wind turbine pictured below is extreme, to the point of destruction. That turbine is beyond repair.
Now imagine just for a moment if the wind turbine had been manned or the incident had involved manpower – the feasibility of providing urgent medical treatment to an injured worker in a nacelle at high level is complicated. Often, the physical workplace location of the wind turbine prevents rapid rescue and emergency intervention due to remoteness and accessibility – quite often offshore. By September 2018, the UK wind power sector consisted of 9,088 wind turbines with a total installed capacity of over 20.1 gigawatts: 12,222 megawatts of onshore capacity and 7,907 megawatts of offshore capacity.
Technicians from Vestas, the company that oversees the maintenance of the turbine, attended site in April 2018 to complete a damage assessment. An expert from the company, who specialises in examining wind turbines that have experienced major malfunctions and fires, began an investigation into how the fire occurred.
An engineer hired as part of the insurance claim eligibility process was able to look at the wind turbine and investigate the cause of the fire. According to the engineer’s findings, the turbine experienced an arc flash that caused an electrical fire.
Officials with Vestas have declared the nacelle a total loss, though the tower and foundation are reusable, and will be providing the client with the costs for options ranging from decommissioning of the wind turbine to replacement of the unit.
Clean-up at the site to remove the damaged nacelle occured over the summer but is not expected to be completed before the end of the year.
So don’t ignore The Arc – a few attributable costs of arc flash induced outages and downtime:
- Revenue loss incurred from inability to generate electricity. £100K’s-ish. Minimum.
- Outage period until repairs are complete. Weeks? Months??
- Replacement of damaged or destroyed equipment. Financially, don’t think about it.
- Consequential reputation damage. Immeasurable.
Image: Crown Estates
What Is An Arc Flash?
Hotter than the sun (around 20,000°C) and louder than a bullet, an Arc Flash is when an arcing fault releases dangerous levels of radiant energy, which vaporises metal that spews from the arc. The air is super-heated causing pressure waves that can propel individuals across rooms and create a deadly molten shrapnel.
It goes without saying; the extreme temperatures of an Arc Flash can burn clothing and human skin within fractions of a second, even if the operative is situated five or six metres away from the Arc Flash event. It can also result in an explosive pressure wave that can throw workers across the room and a sound blast that can rupture eardrums.
An Arc Flash event is also accompanied by a bright flash which can cause temporary or even permanent blindness.
Treatment for those that survive an incident can require years of skin grafts, hospital stays and rehabilitation – they may never recover sufficiently to regain their lifestyle, so it’s safe to say that choosing the appropriate PPE is key when it comes to Arc Flash safety.
Posing A Risk
Electrical in nature, Arc Flash poses a substantial risk to those working in the wind industry which is constantly growing in importance due to its potential to contribute significantly to our national energy needs.
When working on wind turbines or windfarms, Arc Flash incidents can occur in both low voltage environments as well as high voltage, with particular reference to the following incidents…
- Opening energised electrical cabinets and verifying zero energy (testing dead)
- Securing and removing lock out and tag out (LOTO) devices
- Conducting trouble shooting on energised equipment and parts
- Working on near or exposed live conductors
- Breaking ground to install turbines
It is worth noting that the above incidents are of broadly the same severity whether the turbine is part of a large commercial windfarm or one of the growing number of small scale turbines installed by businesses.
How To Protect Yourself Against Arc Flash
Arc Flash protection is found in 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.
In addition to quality, it’s important to consider the longevity of the garment – depending on how it’s manufactured it may lose its effectiveness. Always look for products that feature Arc Flash protective qualities in the thread, as opposed to just a sprayed material, which will lose its impact over time.
Arc Flash Risks & How To Prevent Them – Wind Turbines & Windfarms
Overview of Arc Flash Clothing | Contact us to discuss your garment and PPE requirements, we can mitigate risk with guidance on safe working practices and by providing appropriate worker clothing that offers advanced Arc Flash Protection that saves lives every day. Whether working on underground cables or overhead lines, here is a selection of workwear clothing – contact us to discuss your requirements;
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