h/rc 0

[bure961]

All of the h/rc have a minimum arc rating in the ppe table. I see some ppe is listed for nonmelting or natrural fiber in h/rc 0 section. Can this level h/rc 0 produce a arc flash event? Does there need to be a minimum calorie before a arc flash can happen?
Thanks for the help.

 

[petersonra]

All of the h/rc have a minimum arc rating in the ppe table. I see some ppe is listed for nonmelting or natrural fiber in h/rc 0 section. Can this level h/rc 0 produce a arc flash event? Does there need to be a minimum calorie before a arc flash can happen?
Thanks for the help.

As a practical matter the answer is probably that an HRC 0 risk of arc flash approaches nil.

But it is not quite nil.

 

[jim dungar]

You have it backwards. It is the size of the arc flash, and the probability of its occurrence that causes the HRC.

HRC 0 simply says, that in the opinion of NFPA70E these specific tasks will not likely result in 'severe injuries' if 1.2cal/cm? rated PPE is being employed.

This is partly why the NFPA70E group frowns on working the PPE requirements (table 130.7(C)(16)) backwards to a HRC value.