Question:
Hello, good afternoon.
Does the standard contain new information to consider for arc flash analysis?
Thank you
Answer:
No because we’re still on the 2002 edition. The new edition won’t get released until probably next year at the earliest.
As to answering your question, sort of yes and no. Three areas I know will change somewhat:
1. The “lower cutoff” (the old 125 kVA comment/rule) will likely change, probably downward in terms of what is “covered” under this exception but also it sounds like the “1 transformer” part may change to something a little more flexible such as a simple bolted fault cutoff.
2. They have a lot more data to work with. It is my understanding that the 2002 equations are within about 10-15% of the new equations. I’ve seen 3 possible new equations. The first is that EPRI and others have expanded into other areas for “device specific” equations so even though that’s the section that sees little attention, it might change. Second there’s the Wilkins simplified as well as the Wilkins time-domain models. In the past IEEE 1584 kind of covered everything out there and I wouldn’t be surprised if this one does something similar so both get honorable mentions. Both models fit the data a little better. The time domain model is the best but computationally complex to use. Finally I’ve heard that they are getting away from the “jump” that occurs at 1 kV due to the implementation differences between the medium voltage and low voltage models in terms of having a single empirical calculation or at least one that passes through the same point at 1 kV.
3. There has been a lot of discussion and rumbling about a lot more conditons/situations such as having more than just the existing 3 box cases and including electrode orientation which accounts for very problematic situations such as some switchgear. I’d expect that this is where the data gathering is going to have to increase substantially. Everything else just revises the model a bit. READ MORE
