ISpud
Member
- Location
- Prudhow Bay, AK
- Occupation
- Electrical QC Inspector
We are required to have the fire pump service entrance conductors protected, that may be prone to damage outside a facility, (according to NEC 2017 which the client is governing the construction). The code, Article 692.6 requires "...conductors shall be protected from fire for 2 hrs...". As we won't be using concrete, what conduit is rated for 2 hrs. of protection that can be partially buried (18"-24"), and enter the bottom (3'-4' AGL) of a Water/Waste Water (W/WW) facility?
We'll run 3#6+#6GC, MC-HL, 600V Insul Rating, 480V/ 60A from one facility motor control center to the W/WW facility partially in cable tray, buried for a few feet, then from direct burial up to the bottom of the W/WW facility (3'-4' AGL). Can we use RMC that will certainly hold up better than the 20 sec EMT mentioned in a previous thread?
Lastly, even though the RMC or 2 hr rated conduit might not melt as fast as EMT, would the conductor insulation not withstand the high temperature and eventually short out?
We'll run 3#6+#6GC, MC-HL, 600V Insul Rating, 480V/ 60A from one facility motor control center to the W/WW facility partially in cable tray, buried for a few feet, then from direct burial up to the bottom of the W/WW facility (3'-4' AGL). Can we use RMC that will certainly hold up better than the 20 sec EMT mentioned in a previous thread?
Lastly, even though the RMC or 2 hr rated conduit might not melt as fast as EMT, would the conductor insulation not withstand the high temperature and eventually short out?