Arc flash on single phase or DC systems according to NFPA 70E?

[JPEG]

Hi everyone,

I know that IEEE 1584 equations are only for 3-phases AC systems.

But in NFPA 70E, I cant see anything else about system limits but 50V to ground or more.

Anybody knows if we can use NFPA 70E equations on single-phase or DC systems if a customer wants it?

 

[dpc]

There is no definitive guidance on this, as far as I know. For single-phase ac, if you calculate as an equivalent three-phase system using IEEE 1584 equations, the results should be conservative.

For dc, I think you're on your own at this point. I think EDSA claims to do arc-flash calcs for dc, but there's no official basis for the equations they use to calculate it.

 

[Zogzog]

What software are you using?

Last I heard 70E group was working on developing DC equations but I dont think there are any yet, I was advised in the past to use AC equations until then.