The Arc Flash Risk in Electric Metering

The Arc Flash Risk in Electric Metering

There are millions of electricity meters across each country around the world. The quality of these meters varies from very modern installations to very old assets which are deteriorating. 

One important fact:  there are certain activities undertaken by a meter operator that can only be conducted ‘live and it’s important if you are responsible for people working with electricity and gas meters for that matter of the inherent arc flash risks.

The primary risk for a meter operative/engineer are activities involving the cut-out so that is:-

1. The initial withdrawal of the fuse carrier.
2. Testing polarity and (if carried out) measuring voltage
3. Insertion of a shroud
4. Checking the tightness of connections within the upper cutout
5. Withdrawal of shroud
6. Re-insertion of the cut-out

In addition to these activities, there is also an additional risk around metal-clad cut-outs and the opening of the cover. As the cover is conductive if there is a problem with the hinges, or if the cover is in fact unhinged, it can drop and come into contact with energised conductors causing an arc event.

A similar risk can exist around multi-way distribution boards should any of the buzz bar covers be missing internally. This cannot be established before the opening of the cover.

Indicative Arc Flash Incident Energy Calculations for Metering

  • Common Domestic Estate Style Property with 240V Meter: If the premises are fed by a 100A protection device upstream then generally the incident energy is generally no greater than 4 Cal/cm²
  • Farmhouse/Rural Cottage style Property: If the premises are fed by a 100A protection device upstream then generally the incident energy is usually between 0-4 Cal/cm2. IF however it is fed by a protection device rated above 100A and is not protected by a fuse then incident energy is likely to be greater than 4 Cal/cm²
  • Commercial Property with 415V Meter: If the premises are fed by a 100A protection device upstream then generally the incident energy is usually between 0-4 Cal/cm². If fed by a protection device rated above 100A and is not protected by a fuse then incident energy is likely to be considerably greater than 4 Cal/cm²

SKANWEAR® will not be held liable for this information and is shared based upon our experience and knowledge of a variety of situations. You should make your own risk assessments and calculations where required.

Law & Legislation

There have been several life-changing injuries to meter operators/engineers with engineers being hospitalised for extended periods of times with repeated skin grafts being required on their hands, arms and face. Typically engineers have not been wearing adequate PPE protection which is required by law in many countries including the UK.

Electricity at Work Regulation 1989. According to HSE Regulation 14 Work on or near live conductors;

No person shall be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material 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.

Affects of wearing inadequate PPE

Affects of an Arc Flash on Arc Flash Clothing and Non-Arc Flash Clothing

Bottom Line:

If you have engineers working on or near live or potentially live electricity then it is very likely you are exposed to the risk of an Arc Flash or Electric Shock. Adequately protecting your people and organisation is paramount.

Understanding the risk and creating meaningful steps to mitigate that risk is something each organisation is responsible to do. SKANWEAR have a dedicated technical team that works through the hierarchy of controls assisting clients in ways to:

  1. Eliminate the Risk by Physically removing the risk
  2. Substitute the Risk by Replacing the Hazard
  3. Engineering Out the Risk by Isolating people from the Hazard
  4. Use Administrative Controls to Change the way people work
  5. Mandate Correct PPE (Personal Protective Equipment) – Last but not least!

To speak to a technical advisor for support, contact email:  Anthony.long@skanwear.com

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