When I questioned personnel on the comfort of the arc flash PPE currently in use, I found that they were not wearing the currently issued PPE correctly due to the discomfort of wearing the PPE, particularly when the ambient temperatures were high. It was a direct result of the lack of a quantitative and qualitative risk assessment that led to a situation where personnel were too hot in warm weather resulting in excessive perspiration possibly leading to dehydration. There was also restricted movement due to the specification of the PPE. Staff complained of not being able to get in and out of all-terrain vehicles and gloves were often removed in order to work. This all meant that the company electrical safety policy was not being followed and also the cost of PPE was unnecessarily high.

12.15 “Am I responsible for the competence of my contractors?”

The fact is that you are responsible. Even if the nature of the work is outside your own competence you will be expected to show due diligence when appointing a contractor. For instance, I remember presenting a strength and capability study to Health and Safety Executive inspectors from the COMAH (Control of Major Accident Hazards) team on behalf of a manufacturing client. The client had subcontracted the operation, maintenance and control of their entire high voltage network to the local Distribution Network Operator (DNO). The DNO had applied their own locks to the high voltage switchgear and transformer tap changers and were operating the system as if they owned it was an extension to their public electricity network. A question was put to my client “how do you know that the DNO is competent?” I must admit that I was a little surprised by the question at first but, having fairly extensive personal knowledge about the outsourcing of high voltage operation maintenance contracts, I could see where the inspector was coming from. Whilst it seemed to be a rhetorical question at first, it clarified that you can subcontract the maintenance but not the responsibility. The fact is, the client owned a high voltage network and it was on their land so anyone entering their site had to be under the appropriate supervision of the duty holder. For this client and others in similar circumstances, I have written specific management of high voltage systems procedures and delivered training to ensure that they fulfil their duty of care to contractors. The procedures were very specific to the site so laid down what, where and when of operational and maintenance responsibilities and activities including emergency situations.

Another example was a prosecution of a food manufacturing plant after the employee of one of their contractors was killed in an electrical accident. Although it was an electrocution case rather than arc flash, it was very clear about the duty holder’s responsibilities when it came to contractors from the following press release. “A contractor’s employee was removing a redundant cable from a trunking and was killed when he made direct contact with an un-insulated live cable at an in-line connector joint. The subsequent HSE prosecution resulted in a fine of £220,000 and £30,000 costs to the company ordering the work for (i) not ensuring that the subcontractor was sufficiently competent to perform such work and (ii) not ensuring a safe system of work was in place.” Other examples are from my experiences where I have, on several occasions found engineers working in energised high-power electrical equipment, with few formal electrical qualifications. One area of concern has been large refrigeration control equipment which often contains high current low voltage bus bar systems. As a result, the incident energy levels are frequently of a high level and could cause severe injury or even death. However, electrical training is purely supplemental to some refrigeration engineers that I have come across and sometimes just a skill that has just been acquired over time.

Learning Points
  • (12.1) Arc Flash is much more than PPE.
  • (12.1) Arcing faults can cause huge losses that are not related to personal protection.
  • (12.1) Consider the possible environmental impact.
  • (12.2) A competent electrical engineer can determine arc flash hazard severity.
  • (12.2) The tools provided with this guide give the means to determine fault levels and short cuts to provide answers quickly and without the need for complex software.
  • (12.4) There is an implied requirement in Law to take account of the arc flash hazard.
  • (12.4) All hazards should be considered in Risk Assessments.
  • (12.6) NEVER plug circuit breakers or relays into LIVE electrical equipment.
  • (12.6) Incident energy at the hands is often of much greater magnitude than the body and face.
  • (12.6) Burns from arc flash are often difficult to treat.
  • (12.7) Carry out a rigorous risk assessment before working on or near live equipment.
  • (12.7) NEVER work on or near damaged electrical equipment or conductors.
  • (12.7) Beware of the traps left by colleagues.
  • (12.8) Arc duration is not always measured in milliseconds.
  • (12.8) Arcing faults are extinguished only if: The source collapses; the protection operates; the arc cannot be sustained.
  • (12.9) Design Engineers should consider arcing faults on large power systems.
  • (12.9) Enhanced protection should be considered if necessary.
  • (12.9) Do not put additional impedance between transformers and switchboards.
  • (12.10) Just because you can plug it in does not mean that it is safe to do it live!
  • (12.10) Speak to the Manufacturer.
  • (12.10) DO NOT take risks!
  • (12.11) DO NOT rely on equipment that is finger safe.
  • (12.11) Substations and Switch rooms are dangerous places for unqualified staff.
  • (12.12) Establish the competence of ALL electrical workers.
  • (12.12) Undertake Panel Inspections and Risk Assessments.
  • (12.13) DO NOT put young people in harm’s way.
  • (12.13) The Dominos: Unsafe practice; work at height; equipment manufacturing defect; electrical design flaw; protection failed to operate; no personal protection; accident; injury.
  • (12.13) Carry out a risk assessment.
  • (12.13) Remember the human factors - Fatigue.
  • (12.13) Do not rely entirely on equipment design to eliminate the hazard.
  • (12.14) The arc flash hazard is often greater at LV than it is at HV.
  • (12.14) Carry out the four P approach.
  • (12.14) Remove the need for heavy duty PPE.
  • (12.15) You are responsible for the competence of your contractors.
  • (12.15) Outline the minimum requirements for competence.
  • (12.15) Ensure that contractors work under your rules including for competence assessment.