How to predict when an Arc Flash might occur

How to predict when an Arc Flash might occur

There are lots of factors to consider when thinking about how to predict when an Arc Flash might occur. Here we give a brief overview of what you need to know and do in order to properly understand the risks and predict when an Arc Flash incident is more likely.

The hierarchy of control is commonly used to assess and understand risk – read more about it here. This article will discuss just a few aspects of that hierarchy.

Using Arc Flash studies to predict when incidents might occur

Carried out by a qualified electrical engineer usually using dedicated software, an Arc Flash study will analyse the whole of a facility with an on-site evaluation, Arc Flash modelling using original drawings, and will use the results of a short circuit and coordination study.

The output of an Arc Flash study will be details of the potential incident energy – the measure of how severe an Arc Flash is – at each piece of equipment posing a risk, along with the incident boundary – how far away someone would need to be before PPE is needed. 

Using this information, equipment can be labelled and risk assessments carried out, which may result in different types and/or ratings of PPE being recommended. 

Using risk assessments to keep you safe from Arc Flash

Anyone working in an operational role will be used to making reference to risk assessments. They should be part of a much larger programme and culture of health and safety and will provide insight into the steps both the organisation and the workers need to take to keep themselves safe. 

In order to make sure they take account of current understanding and best practice, risk assessments need to be regularly updated – every five years or whenever a major change is made to an installation or facility would be a reasonable period of time. 

Risk assessments will take some information from an Arc Flash study but tend to be specific to either an action or a piece of equipment. In short, an Arc Flash risk assessment will predict when an Arc Flash incident could occur by:

  1. Identifying a hazard
  2. Estimating the likelihood of an incident and the potential severity of injuries as a result (the risk)
  3. Recommending whether additional protective measures are needed

Fixed risk assessments are no substitute for dynamic risk assessments – those carried out in the moment and at the time work is about to be undertaken – so adequate training for your electrical engineers will also help them to predict when an Arc Flash might occur so they can take steps to avoid it.

How to predict an Arc Flash – risky activities

You can argue that everything we do carries a risk – according to ROSPA, more accidents happen at home than anywhere else, with 6,000 people dying every year as a result of an accident at home. 

But it’s clear that some activities will be more risky than others, especially in the context of Arc Flash. Particularly risk activities include:

  • Breaking ground – service maps aren’t always accurate, leading to striking cables or pipes not marked on the map. In 2016 an operative’s life was saved by wearing one of our polo shirts when he struck a 120 CNE 3 Phase low voltage cable which led to an Arc Flash
  • Working on energised equipment – it should go without saying that the risks of any kind of electrical incident are increased when power is live
  • Working in electrical cabinets – In Mitigation of high energy arcing faults in nuclear power plant medium voltage switchgear, by Choong-koo Chang, published in February 2019 in Nuclear Engineering and Technology, Chang says: “The most likely place where HEAF can occur is in the electrical cabinets. Among the… twenty-one events, nine events occurred in the electrical cabinets, five events occurred in the cableways (bus duct, bus bar, and cable runs), four events occurred in the transformers, and remaining three events occurred in the circuit breakers.”

Arc Flash PPE – the last line of defence

At the bottom of the hierarchy of control, once all risks have been managed and minimised, is PPE. Understanding the correct types and ratings for personal protective equipment that will help protect you and your crews from an Arc Flash incident is critical. This information, in the form of a cal rating, will be available as a result of the Arc Flash study. 

While we can’t advise specifically on how to predict when an Arc Flash will occur, using the information from your Arc Flash studies and risk assessments our experts can recommend what PPE is most appropriate for you – call them on +44 (0) 1482 679600.

Make sure that you’re specifying the right PPE for your team.

Read our free guide on the top considerations when choosing Arc Flash clothing & PPE below and make the best choice for you and your team via the link below ⬇.

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