Arc Flash Compliance

Electrical Safety UK can advise you about compliance with UK legislation with regard to arc flash and compliance with the Electricity at Work Regulations in general. Our Principal Engineers are fully conversation with UK legislation and can advise you on where you may have gaps and could be open to criticism by the Regulatory Authorities. We can also provide you with expert advice in the event that your organisation has suffered an accident. We can also act as your expert legal witness in court.

The Electricity at Work Regulations 1989 defines “Injury” and “danger” as:

“injury” means 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;

“danger” means risk of injury;

Section 2 Guidance Item 37 Electric Burn states:

“…. Electrical arcs jump across gaps and can cause burns.”

Section 2 Guidance Items 41-43 states:

“Arcing

41 Arcing causes a particular type of burn injury which is distinct from other types. Arcing generates ultraviolet radiation which causes damage similar to severe sunburn. Molten metal particles from the arc itself can penetrate burn and lodge in the flesh. These effects are additional to any radiated heat damage caused by the arc.

42 On its own, ultraviolet radiation can cause damage; sensitive skin and eyes are especially vulnerable to arc flash. (‘Arc eye’ is commonly encountered with electric arc welding if the proper precautions are not adopted.)

43 Arcing faults can occur if the energy available at a piece of electrical equipment is sufficient to maintain a conductive path through the air or insulation between two conductors which are at different potentials. Under fault flashover conditions, currents many times the nominal rating or setting of a protective device may flow before those devices operate to clear the fault. Much energy is dissipated in the arc and, depending on the electrical protection, may continue long enough to inflict very serious arcing burns or to initiate a fire. These periods can be as short as 0.2 seconds. Arc flashovers caused during work on live circuit conductors are likely to be particularly hazardous because the worker is likely to be very near to or even enveloped by the arc. Such cases often lead to very serious, sometimes fatal, burn injuries.”

We can see that arc flash hazards are recognised by the legislation as hazards associated with electrical energy that could give rise to danger.

Regulation 4 Systems, work activities and protective equipment (3) states:

“Every work activity, including operation, use and maintenance of a system and work near a system, shall be carried out in such a manner as not to give rise, so far as is reasonably practicable, to danger.”

This Regulation makes it clear that operation, use and maintenance of your electrical system needs to be carried out safely and as such you should consider arc flash as part of your risk assessment processes. Your risk assessments need to consider each hazard, the severity of each hazard, as well as the likelihood of that hazard being realised. In the case of arc flash, unless you have carried out an arc flash study it is unlikely that you have been able to correctly quantify the arc flash hazard on each piece of equipment. The arc flash hazard on each piece of equipment can be quantified by calculating the incident energy level in Cal/cm².

Regulation 4 Systems, work activities and protective equipment (4) states:

“Any equipment provided under these Regulations for the purpose of protecting persons at work on or near electrical equipment shall be suitable for the use for which it is provided, be maintained in a condition suitable for that use, and be properly used.”

We can see from this regulation that if arc flash personal protective equipment is going to be used as a control measure to mitigate arc flash risk it needs to be correctly rated. If you do not know the incident energy level of the equipment you are working on, you cannot determine what level of protection is required from your arc flash PPE. The arc flash PPE rating needs to be at or higher than the incident energy level that you could be exposed to. So again, an arc flash study is required to determine the worst-case incident energy level for each piece of equipment on your electrical network

Regulation 4(3) is wide in its application and includes work of a non-electrical nature where there is a risk of electrical injury. A common example is excavation near to live electric power cables and work near live overhead power lines, where the risks can be severe. Electrical Safety UK has helped several organisations (Utilities, Telecoms and Local Government) to determine the likely arc flash hazard when excavating. This has then enabled us to provide guidance by carrying out a risk assessment on how best to mitigate the arc flash hazards.

Regulation 14 Work on or near live conductors states:

“No person shall be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material so as to prevent danger) that danger may arise unless –

(a) it is unreasonable in all the circumstances for it to be dead; and

(b) it is reasonable in all the circumstances for him to be at work on or near it while it is live; and

(c) suitable precautions (including where necessary the provision of suitable protective equipment) are taken to prevent injury.”

Whilst working on or near live conductors should be a rare event on electrical systems, it is sometimes necessary. The other thing to consider is that fault finding on equipment that is insulated to prevent accidental touching of live conductors can rely on the fact that equipment was designed and built to meet the requirements of the Ingress Protection Level 2X. As equipment ages it is not uncommon to see IP2X protection is comprised i.e. shielding missing, insulation damaged, covers missing etc.

Regulation 3 (1) Risk assessment states:

“Every employer shall make a 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 and prohibitions imposed upon him by or under the relevant statutory provisions”

In the case of arc flash, it is clear that it falls under these Regulations, and that to risk assess arc flash, the hazard must be quantified by calculating the worst-case incident energy levels of each piece of equipment on the network. Therefore, an arc flash study is required.

Regulation 4 Provision of personal protective equipment. Regulation 4(1) states:

“every employer shall ensure that suitable personal protective equipment is provided to their workers who may be exposed to a risk to their health or safety while at work except where and to the extent that such risk has been adequately controlled by other means which are equally or more effective”

Regulation 4(3) states:

 Without prejudice to the generality of paragraphs (1) and (2), personal protective equipment shall not be suitable unless –

(a) it is appropriate for the risk or risks involved, the conditions at the place where exposure to the risk may occur, and the period for which it is worn;

(b) it takes account of ergonomic requirements and the state of health of the person or persons who may wear it, and of the characteristics of the workstation of each such person;

(c) it is capable of fitting the wearer correctly, if necessary, after adjustments within the range for which it is designed;

(d) so far as is practicable, it is effective to prevent or adequately control the risk or risks involved without increasing overall risk;

(e) it complies with any legal requirement which is applicable to that item of personal protective equipment.

Under the PPE Regulations we can see that again there is a requirement to risk assess before asking personnel to wear PPE. Again, with arc flash we must consider how we would quantify the hazard and again I would suggest that an arc flash study is the only sensible way to do this.

How much money should you be spending on Arc Flash Risk Management?

Let’s first take a look at what the Electricity at Work Regulations guidance says about as low as reasonably practicable.

“Generally, you should do everything ‘reasonably practicable’ to protect people from harm. This means balancing the level of risk against the measures needed to control the real risk in terms of money, time or trouble. However, you do not need to take action if it would be grossly disproportionate to the level of risk.”

In order to give guidance on how much money you should be spending to meet current legislative “ALARP” requirements an assessment needs to be made of how the risk should be managed. United Kingdom Health and Safety Executive (HSE) guidance expects the Duty Holder to comply with current good practice. There is very little specific guidance from the UK HSE on the management of arc flash risk, so this gives us a problem. We should then consider whether the risk is as low as reasonably practicable. To do this we need to consider the cost of implementing the specific control measures, versus the benefits they would give us. At ESUK we have carried out this analysis for a typical small and large industrial/commercial site. A summary of the results showed a spend of £10k-£100k was reasonable and would meet the as low as reasonably practicable (ALARP) requirement. If we then consider that the cost of an arc flash study + staff training + incident energy reduction actions + providing arc flash PPE. The total cost of those actions is likely to put you in the £10k-£100k range. It is very difficult to justify additional more costly remedial work such as retrofitting of: remote switching; arc flash relays; fast-acting earthing devices etc… It is also very difficult to justify replacement of electrical equipment e.g. switchgear, switchboards etc purely for arc flash hazard mitigation reasons. However, if your Company has a lower tolerance to risk than that required by legislation you may need to consider spending limits higher than the guidance above. Your company risk tolerance criteria are normally set out by your Health and Safety Department.