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Re: Arc flash calculations with generators

This is most certainly a topic that needs to be addressed. 

You are also most assuredly correct in your analysis of the issue- these are NOT infinite capable machines, and should not be treated as such. 

In our quest for safe working conditions are we needlessly burdening our technicians? They have limited space, time and resources. We have all seen and heard the horror stories, and do not wish to repeat them, but what is a reasonable balance?  Safety precautions need to be effective and appropriate.

Thanks for bringing it up, i relinquish the soapbox...

Walt

 

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Arc flash calculations with generators

When power is supplied by a generator, the arc flash calculations in NFPA 70E and IEEE 1584 don't work, because they assume the arc energy is constant, and with generator source it is constantly changing according to the generator decrement curve.  This affects both the fault clearing time and the arc energy.  Has anyone in this group investigated this problem and come up with a solution?  Or if not, is there any interest in forming an informal manufacturers' group to address it in the standards?

 

Regards,

Allen