Electric Fire pump madness

Status
Not open for further replies.
jim dungar said:
Actually it is quite clear.
The last sentence of NEC 2014 Article 695.4(B)(2)(a)(1) says:
" The requirement to carry locked-rotor currents indefinitely shall not apply to conductors or devices other than overcurrent devices in the fire pump motor circuit(s)."
Click to expand...
Thanks Jim. I have read that many times and missed it. No OCPD no need to rate for locked rotor Amps. What are your thought on a fire pump service fed directly from a pad mount (second service) to a CT cabinet. From the CT cabinet to an disconnect disconnect w/o OCP from the disconnect to the fire pump Overhead thru the building in 2 hour fire rated circuit protective system. Without the OCP in the disconnect is it a feeder and no longer service entrance conductors. Does 90.3 allow non compliance with 230.90 in said disconnect?
 
If you use a non-fused disconnect as the fire pump service disconnect, it will have a horsepower rating. If the rating is equal to or greater than the fire pump, then it will be able to interrupt the locked rotor current.
 
JoeStillman said:
If you use a non-fused disconnect as the fire pump service disconnect, it will have a horsepower rating. If the rating is equal to or greater than the fire pump, then it will be able to interrupt the locked rotor current.
Click to expand...
I assume there is some standard that sets what the locked rotor current (LRC) is for a given HP rating. If the intent is to satisfy 695, you need to be sure that the LRC assumed in the listing for the disconnect is the same or greater than that called out in NFPA 20.
 
JoeStillman said:
If you use a non-fused disconnect as the fire pump service disconnect, it will have a horsepower rating. If the rating is equal to or greater than the fire pump, then it will be able to interrupt the locked rotor current.
Click to expand...
The OP was about needing to carry the LRA continuously not simply interrupting it.
 
Status
Not open for further replies.
Top