|
0 members (),
228
guests, and
10
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
|
Joined: Mar 2005
Posts: 240
OP
Member
|
i have a sub 50 amp sub panel that i want to put in a detached maint/gar building. to save money on wire i am going to run two #6's for the lines and one #8 for the neutral(derating the neut)along with a #10 ground. my question is does this sound code compliant, we derate neutrals for the service feeders and this is going to be a feeder so it seems very complicit to me.
am i on the right page? any codes that i am missing which would forbid this derating? thanks guys, h20
|
|
|
|
Joined: Mar 2005
Posts: 240
OP
Member
|
oh yea it is a metal building which i will bond the beam structure and will drive two ground rods down at the building too.
|
|
|
|
Joined: Jan 2004
Posts: 1,507
Member
|
By not knowing what your load is, I can't tell you that you can or can't derate the neutral. Also, I would be interested in how you terminate the neutral and ground wires in the sub panel. Where do you connect the Grounding Electrode Conductor in the sub panel?
George Little
|
|
|
|
Joined: Jun 2005
Posts: 821
Member
|
|
|
|
|
Joined: Dec 2003
Posts: 751
Member
|
Hold on. You must ALWAYS install a grounding electrode system for a detached building with more than a single multiwire branch circuit. It doesn't matter if your have three or four wires; with or without an equipment grounding conductor. see 250.32
Earl
|
|
|
|
Joined: Dec 2003
Posts: 751
Member
|
The neutral may only be derated if there is sufficient straight 240 volt loads to warrant it. see 220.22
Earl
|
|
|
|
Joined: Apr 2004
Posts: 60
Member
|
If your neutral busses are specifically listed at 75C and you use 75C rated wire, then #8 copper is fine for a 50A feeder because that wire is still rated at 50 amps.
Mark Kent, WA
|
|
|
|
Joined: Jun 2005
Posts: 821
Member
|
My bad.
Yes, a grounding electrode MUST be installed on any detached building.
|
|
|
|
Joined: Aug 2003
Posts: 173
Member
|
Yes, a grounding electrode MUST be installed on any detached building. ...that is fed with a feeder. If you only run a circuit no rod is needed. See: 250.32
Speedy Petey
"Anyone who has never made a mistake has never tried anything new." -Albert Einstein
|
|
|
Posts: 32
Joined: June 2004
|
|
|
|
|