Arc Flash Study on Equipment Above 15kV

[aaronkoe]

I am performing an arc flash study on a 25kV switchgear and wondering what does OSHA now say about this? What standard should i use?

Previously they said above 15 kV, OSHA found that only ARCPRO, a commercially available software package, is acceptable for determining incident energy levels. Above 15 kV, IEEE and NFPA 70E methods are only acceptable for determining where incident energies are below 2 cal/cm2.

I think this has changed in recent updates?

Thank you!

 

[David Castor]

Unless something has changed recently, the OSHA language you are referring to applies to electric utilities with overhead lines and exposed substations. For metal-clad switchgear, you don't want to use ARCPRO - at least I wouldn't. But maybe OSHA has updated their regulations recently.

The IEEE 1584 equations are only valid up 15 kV. Above that, most software packages revert to the old Lee equations.

NFPA 70E has never specified a calculation method that must be used.