Cable Insulation
Cable Insulation
(OP)
I have the following doubt. A office Bldg. have a XTRM (utility owner) that feed a MDP, i understand that the service entrace conductor need to be XHHW (wet location) inside conduit. But what happened between the MDP and the Meter Module, which type of cable I need to specify, each Meter Module will be located in each floor and feed with 500 MCM Aluminum conductor Serie-8000. I can use THHN or I need to specify XHHW, The riser conduit travel through a shaft in the bldg.






RE: Cable Insulation
RE: Cable Insulation
No true. If the conduit is underground then a "W" rating is required. If this is inside the building, any of the conductor type listed in table 310.16 under the 75C col would be ok. You need someone to assist you with an electrical knowledge and familiar with the NEC.
RE: Cable Insulation
RE: Cable Insulation
Don
RE: Cable Insulation
I think you will find cable marked now as THHN/THWN as Don
has said. It is shown in the 90C Col but you can not use that rating. You use the 75C Col rating. I'm not sure why
its not shown in the 75C Col.
RE: Cable Insulation
THWN = 75 C Wet (as indicated by one "H" and "W")
THHN insulated wires are limited to their 75 C ampacity when connecting to breakers or other devices to avoid over temperature of the connection. But the 90 C rating can still be used as the starting ampacity in derating calculations. In other words, the middle of the wire can operate at 90C as long as the ends stay at or below 75C.
RE: Cable Insulation
Don