Copper Wire Size
#1
12-02-03, 06:19 PM
Copper Wire Size
Hi,
I am trying to install a subpanel next to my main panel(like so many 100s of homeowners across the country
).
I purchased a SquareD QO 1 load 100amp 8 space 16circuit main lugs panel to act as my subpanel. I also purchased a 100amp breaker to install in my main panel, to feed the sub. Also the new subpanel is will be within 18"-24" of the main and currently I have purchased two 15amp & one 20amp tandem breakers for the sub. It will never need anything higher than a 20amp breaker.
SOOOO, my question is what size wire do I need to make the connection between the 100amp breaker in my main and the subpanel?
3/3 wgrnd
3/2 wgrnd
2/3 wgrnd
2/2 wgrnd
2/0(I DON'T EVEN KNOW IF IT COMES WITH GROUND or do I need to purchase a seperate #8 ground)?
What are the differences in the above wires and/or applications for each?
THANKS.
I am trying to install a subpanel next to my main panel(like so many 100s of homeowners across the country
).I purchased a SquareD QO 1 load 100amp 8 space 16circuit main lugs panel to act as my subpanel. I also purchased a 100amp breaker to install in my main panel, to feed the sub. Also the new subpanel is will be within 18"-24" of the main and currently I have purchased two 15amp & one 20amp tandem breakers for the sub. It will never need anything higher than a 20amp breaker.
SOOOO, my question is what size wire do I need to make the connection between the 100amp breaker in my main and the subpanel?
3/3 wgrnd
3/2 wgrnd
2/3 wgrnd
2/2 wgrnd
2/0(I DON'T EVEN KNOW IF IT COMES WITH GROUND or do I need to purchase a seperate #8 ground)?
What are the differences in the above wires and/or applications for each?
THANKS.
#2
12-02-03, 06:37 PM
Member
You need three insulated #2 copper wires plus a #8 or larger copper grounding wire. Any cable type that you can find that fits these requirements will do, or you can buy indivudual wires and run them through conduit.
#3
12-02-03, 07:52 PM
Originally posted by John Nelson
You need three insulated #2 copper wires plus a #8 or larger copper grounding wire. Any cable type that you can find that fits these requirements will do, or you can buy indivudual wires and run them through conduit.
You need three insulated #2 copper wires plus a #8 or larger copper grounding wire. Any cable type that you can find that fits these requirements will do, or you can buy indivudual wires and run them through conduit.
If so why not use 2/3 with grnd?
THANKS!
#5
12-02-03, 08:22 PM
Thanks you confused me when you said:
If my understanding is correct, I won't need the #8 grounding wire as a seperate run.
I will just connect a hot to each bus bar, the neutral and ground to thier bus bars respectively.
(I purchased a ground bus bar kit to add to the subpanel).
agains thanks for your help!
Originally posted by John Nelson
You need three insulated #2 copper wires plus a #8 or larger copper grounding wire. ...
You need three insulated #2 copper wires plus a #8 or larger copper grounding wire. ...
I will just connect a hot to each bus bar, the neutral and ground to thier bus bars respectively.
(I purchased a ground bus bar kit to add to the subpanel).
agains thanks for your help!
#7
12-02-03, 08:51 PM
Originally posted by John Nelson
2/3 with ground is three insulated #2 copper wires plus a #8 copper grounding wire.
2/3 with ground is three insulated #2 copper wires plus a #8 copper grounding wire.
Thanks again.
p.s.
Where can I get info on specific gauge and the corrensponding ground?
For example 12/3 or 14/2?
Tomorrow is the big day, when I cut off the main switch, stick in my 100 amp breaker and wire it up to my new sub.
#8
12-02-03, 09:02 PM
Member
Not sure exactly what you are asking, but Table 250.122 of the NEC specifies the minimum size equipment grounding conductor. For all circuits 30 amps or less, the minimum size EGC is the same as the conductor size.
#9
12-02-03, 09:11 PM
Originally posted by John Nelson
Not sure exactly what you are asking, but Table 250.122 of the NEC specifies the minimum size equipment grounding conductor. For all circuits 30 amps or less, the minimum size EGC is the same as the conductor size.
Not sure exactly what you are asking, but Table 250.122 of the NEC specifies the minimum size equipment grounding conductor. For all circuits 30 amps or less, the minimum size EGC is the same as the conductor size.
