Arc Flash Analysis Step by step #0
What exactly is arc flash?
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What is Arc Flash?
Arc Flash also known as flashover, electric arc, arcing fault, etc. An electrical arc is a form of electrical discharge between two electrodes (anode and cathode). The name arc comes from the shape of discharge paths due to gas convective motion. Due to gas ionization process it creates stable arc path which is heating up the gas and can reach up to 19000 °C. We are using this in controlled way in electrical welding machines or electric furnaces. Problems start when it happened unintentionally or by accident.
Why I need to care about it?
Arc Flash as I wrote above can produce temperatures up to 19000 °C. When it happens in our electrical installation by accident, we need to be protected against it. For example, to get 2nd degree burn, we need 0,1s of 80 °C or 0,9s of 65 °C hot water. As you may see there is a huge gap, and you need to prepare for it in advance as It will be too late once it happens. I like the comparison to driving a car on the highway without seat belts or cleaning load gun in front of your face.
What to do next?
When it comes to arc flash there are multiple solutions, but before we jump into solving anything it is good to understand:
- what we need to improve
- where improvement is needed
- why we need to do it
To do it in the right way, we need to identify possible arc flash incident energy levels in electrical installation. This is important as it allows us to:
- identify incident energy for complete installation for proper overview
- identify locations on which we need to focus
- prioritize actions for improvements where it is needed at most
- create short term plans for fast solutions (e.g. fast PPE exchange)
- prepare planning and cost overview
At the end it will save us time and money as we can target precisely where to invest or improve safety. Not to mention that as recent fines show (£600,000) it is much, much, much, much cheaper to be compliant than cost of possible accident and related fines in case of safety violations.
Usually, for EU and worldwide customers, the best references are:
- NFPA 70E table method
- NFPA 70E analysis method by IEEE 1584 (recommended)
See my next articles from Arc Flash Analysis Step by Step series.
