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Guest Article | The following article has been republished with the kind permission of Integrum Power Engineering.

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Integrum Power Engineering are committed to providing highest quality engineering services and solutions designed to add value to their clients’ businesses whilst maintaining a zero-harm approach to safety and the environment – operating in all sectors and industries where power distribution engineering services are required, including renewables, utilities, oil and gas, mass transit, private networks and independent connections.

LV HV Power Engineering Services:

• Network modelling and fault analysis
• Power distribution network protection scheme design
• Protection relay settings and Programmeable Scheme Logic
• IEC 61850 substation automation design
• Protection transformer sizing and specification
• Protection & Control and SCADA interface design
• Substation earthing system analysis, modelling and detailed design
• Substation LV and domestic services design
• Substation protection & control panel secondary design

Last year an article had been produced assessing the types of Arc Flash Risks and the prevention of those same risks through the implementation of effective Arc Flash Clothing & PPE for workers in the UK Highways & Street Lighting industry.

With the incident at Network Rail’s Godinton Substation in December 2018, still at the forefront of our minds at Integrum Power Engineering, the question that has been raised is: “Do we do enough to Protect Civil & Utility Contractors within the railway boundary?”

What is ARC Flash?

Electrical arcing (sometimes called a ‘flashover’ or ‘arc flash’) can generate intense heat leading to deep-seated and slow healing burns. The intense ultraviolet radiation from an electric arc can also cause damage to the eyes.

Arc Flash PPE Safety

An arc fault is similar to the arc obtained during electric welding and the fault has to be manually started by something creating the path of conduction or a failure, such as a breakdown in insulation or contact with a conducting object.

When the air quality or insulation is degraded with moisture or other impurities, the possibility of an arc striking is increased. The arc column temperature can vary from 5,000ºC to 20,000ºC and the intense heat can vaporise the conductors and surrounding materials.

It can cause severe shock waves, splattering of molten debris, loud explosions due to the rapidly released vapour, as well as shrapnel and serious burn injury to anyone in the vicinity. The arc has a tendency to move away from its source.

What do the statistics tell us about ARC flash incidents?

Cable strikes are one of the most common causes of an Arc Flash, with approximately 60,000 strikes taking place in the UK per year.

The HSE states that around 1,000 workplace electrical incidents are reported to them each year, with around 25 people a year dying from their injuries.

It can be assumed that the proportion of incidents which resulted in life changing injuries or death being caused by Arc Flash incidents are likely to be even higher.

Alarmingly, ProGARM’s recent research revealed that a staggering 57% of electrical workers had first-hand experience of an Arc Flash incident having experienced or seen someone else suffer a strike during their career. This supports that the frequency of Arc Flash incidents that occur are far higher than the officially reported electrical incident statistics to HSE.

Despite being extremely dangerous – potentially fatal for those caught in one – the UK’s Health & Safety Executive (HSE) categorises such reportable incidents together with all other electrical work incidents.

ARC Flash UK Legislative

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 is a hazard, and the risks posed are electric shock, burns, fires, arcing and explosion. 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’.

The HSE have concern about ARC flash

There are two types of enforcement notices that have been issued by the HSE that refer to Arc Flash, Improvement Notices and Prohibition Notices. There have been 37 Enforcement Notices issued in the past few years by the HSE that concern Arc Flash. The Enforcement Notices cite the following Legislation and Regulations:

Health And Safety At Work Act 1974 (HASAWA)

This is the “umbrella” legislation that defines how workplace health, safety and welfare is controlled.

• Management of Health and Safety at Work Regulations 1999
• A more detailed document that covers the principles needed to ensure workplace health and safety.
• This covers the need to carry out risk assessments.
• Personal Protective Equipment at Work Regulations 2002
• This implements the requirements of the European PPE directive.
• Provision and Use of Work Equipment Regulations 1998 (PUWER)
• Covering the provision of safe working equipment and the training in its operation.
• Electricity at Work Regulations 1989
• General electrical regulations that cover working on or around electrical equipment including live systems.

Network Rail’s response to godinton substation incident

Following the Godinton incident, the minimum requirements for Arc Flash PPE have been enhanced.substation incident

But the enhancements are only limited to Distribution & Plant maintenance and projects staff who undertake work inside traction / non traction distribution locations, which are required to wear the following at all times:

Main layer – Arc Flash polo shirt and Arc flash cargo trousers
Any Base layer underclothes MUST be either natural 100% cotton or approved flame retardant items

DOES THE NETWORK RAIL RESPONSE GO FAR ENOUGH?

In May 2015, an Injured Person (IP) undertaking work on behalf of Amey was removing the bottom of a concrete service box with a hand-held breaker machine to lay a cable duct in a non railway environment. The IP hit a live 11,000Vac cable that was under the box and received an electric shock. The IP’s clothing caught fire and sustained serious burns to their face, chest, arms, hands, legs and stomach.

The IP was put in a medically induced coma for two weeks and has undergone several skin grafts. The accident also affected their eyesight and heart rhythm, while nerve damage means they no longer have full use of their left hand. The IP still attends physiotherapy appointments and has been unable to return to work.

Amey stopped work immediately after the accident and has since reviewed its safety procedures and operating practices. Amey now mandate the requirement that all workers wear arc flash personal protective equipment. Amey has also appointed an Electrical Duty Holder and improved its risk assessment process and increased supervisor training.

Operatives are exposed to arc flash risks if correct digging procedures are not followed while excavating underground electricity cables – operatives have suffered arc flash burns when digging with a hammer drill directly above an identified live buried cable. Upon making contact with even a 415Vac street lighting cable, ‘arc flash’ would still occur resulting in burns to the wrist and elbow and a visit to the hospital A&E. Never dig directly over an identified live buried service. Powered hand tools used close to live cables are likely to represent the greatest risk of injury.

What does ARC Flash risk management good practice look like?

In brief, good practice can be achieved by implementing certain tasks:

• Calculate the Arc Flash Incident Energy Levels and Arc Flash Boundary Distances on each piece of equipment that is connected to your Electrical Distribution Network.
• Label the equipment with the calculated values and recommended Personal Protective Equipment (PPE) that could be used to mitigate the risk.
• Reduce the arc flash incident energy levels. (where practicable)
• Carry out task-based arc flash risk assessments on the equipment with the highest levels of incident energy.
• Give your staff the competence to understand Arc Flash Risk and how they can mitigate it.

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External URL: https://www.powerandcables.com/arc-flash-ppe-safety-guidance/