An arc flash analysis is something that has been getting mixed up in recent years.
Some believe it’s a detailed and impossibly elaborate engineering assignment... others would liken it more to assessing the risk before stepping across a set of train tracks.
But who right? Well... if you asked someone on the technical committee for NFPA or CSA they would tell you that both were wrong.
The two terms we need to talk about are Incident Energy Analysis and
Arc Flash Risk Assessment.
What is an incident energy analysis?
Incident energy is the amount of heat energy that can be created by an Arc Flash.
When a piece of electrical equipment explodes, and an Arc Flash is generated there is also an extreme amount of heat... along with a fire ball, smoke, sound, light and debris.
But it’s the heat energy that we are primarily concerned about.
An incident energy analysis is an engineering exercise which calculates each of these individual incident energy levels on each part of your electrical distribution system.
If you’re interested in learning more about how to complete one of these you can visit this article for a ton of information.
I think this is what most people are getting at when they are talking about Arc Flash Analysis... but I could be wrong.
An Arc Flash Risk Assessment is doing one of two things.
The first would be referencing your detailed equipment labels to determine what the incident energy is before starting your task, or:
Secondly, looking at the arc flash hazard category tables in NFPA70E (find out what changes to NFPA70E could impact you) or CSAZ462 to determine what the category is... we might have to explain this in another article, but a category is really a range of potential incident energy levels based on some educated assumptions.
Ultimately, your arc flash risk assessment is a step in your overall job plan that determines the severity of the potential hazard and the likelihood of occurrence of that hazard.
What should I do for arc flash analysis?
Really... you should be doing both.
Take the time or spend the money to determine your arc flash incident energy levels and perform an arc flash risk assessment prior to starting every job.
These two things go hand and hand and are not a substitute for one another.
At the end of the day, it doesn’t matter what you call it... you need to determine the hazard and figure out how likely you are to being exposed to it.