NFPA 70E archflash
NFPA 70E archflash
(OP)
I have a generator room and was wanting to set the Instantenous portion very high or not at all to coordinate better with my downstream devices and the alternative to that is very high arc flash. So here is my thought I tie the door contacts and motion sensor for the room into the instantenous portion of the circuit breakers. My thought is while nobody is in the room then arc flash is irrelevant.
My concern is while somebody's in the room and the generators aren't on therefore the instaneous portion is on and the generators fire up I just have to coordinate any inrush with my temporary instaneous.
Any other concerns?
My concern is while somebody's in the room and the generators aren't on therefore the instaneous portion is on and the generators fire up I just have to coordinate any inrush with my temporary instaneous.
Any other concerns?






RE: NFPA 70E archflash
As it is, it is very inconvenient to stay in the gen room when the generator is running.
Rafiq Bulsara
http://www.srengineersct.com
RE: NFPA 70E archflash
RE: NFPA 70E archflash
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: NFPA 70E archflash
RE: NFPA 70E archflash
I highly recommend this solution opposed to not using an instantaneous element in situations where the inst. element interferes with downstream coordination.
RE: NFPA 70E archflash
I strongly disagree. Don't you think about a) damage to the equipment and b) costs due to interrupted processes? Safety first, but it is definitely not the only issue.
There are better solutions than maintenance switch.
RE: NFPA 70E archflash
That comment was in context of the topic of the original thread only. Perhaps a read of Preface to 2009 NFPA 70E would help.
While your concerns are valid, equipment damage due to arc flash is not covered by NFPA 70E or IEEE 1584. NFPA 70E primarily deals with work practice related safety of personnel and generally enforced by OSHA (vs. say electrical inspectors). Until 2000, it only dealt with shock hazards, now it also has included arc flash hazard (to personnel).
Rafiq Bulsara
http://www.srengineersct.com