sub panel installation

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marlboro12

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I'm istalling a 100 amp sub-panel into a garage about 100' away. I got #2 aluminum wire, do I have to use the same size ground wire? If not what size do i need?
 
Re: sub panel installation

#2 is not big enough for 100 amps, even before figuring for voltage drop.

Are you are computer tech or an electrician?

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Re: sub panel installation

George:

Would this installation not be seen as "feeder" if so according to Table 310.15(B)(6) #2 AL is good for 100amps.

Norb
 
Re: sub panel installation

Norb, 310.15(B)(6) could not be used for a garage.

(6) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders For individual dwelling units of one family, two-family, and multifamily dwellings, conductors, as listed in Table 310.15(B)(6), shall be permitted as 120/240-volt, 3-wire, single-phase service-entrance conductors, service lateral conductors, and feeder conductors that serve as the main power feeder to each dwelling unit and are installed in raceway or cable with or without an equipment grounding conductor. For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch-circuit panelboards(s)
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The garage is not a dwelling.

Roger

[ November 12, 2005, 02:09 PM: Message edited by: roger ]
 
Re: sub panel installation

Originally posted by hurk27:
What's a "sub panel?"
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A panel that not as high up on the chain of command as the main panel. :D
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i thought it was a panel that was underground, " sub terranean panel". :eek:

[ November 12, 2005, 09:35 PM: Message edited by: PlnOldRick ]
 
Re: sub panel installation

Originally posted by marlboro12:
I'm istalling a 100 amp sub-panel into a garage about 100' away. I got #2 aluminum wire, do I have to use the same size ground wire? If not what size do i need?
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#2 is not a wire size recognized by the NEC.
What do you mean by ground wire? Do you mean the grounding electode conductor, the equipment grounding conductor, or the grounded conductor?
Personally, I would only install a #2 ground wire if it was a time and materials job.
For your application all three are needed.
This seems like a DIY'er post. Now that I know what a sub panel is, I am going to lock it.
If you disagree, contact the chief moderator.
 
Re: sub panel installation

One more clarification:
" Would this installation not be seen as "feeder" if so according to Table 310.15(B)(6) #2 AL is good for 100amps.

Norb"
No. 310.15 B 6 is only for the main power feeder, which this is not.
 
Re: sub panel installation

#2 is not a wire size recognized by the NEC.
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Tom, why would you say that #2 is not recognized by the NEC. It appears twice in table 250.66 alone.

Table 250.66 Grounding Electrode Conductor for Alternating-Current Systems

Size of Largest Ungrounded Service-Entrance Conductor or Equivalent Area for Parallel Conductorsa (AWG/kcmil) Size of Grounding Electrode Conductor (AWG/kcmil)
Copper Aluminum or Copper-Clad Aluminum Copper Aluminum or Copper-Clad Aluminumb
2 or smaller 1/0 or smaller 8 6
1 or 1/0 2/0 or 3/0 6 4
2/0 or 3/0 4/0 or 250 4 2
Over 3/0 through 350 Over 250 through 500 2 1/0
Over 350 through 600 Over 500 through 900 1/0 3/0
Over 600 through 1100 Over 900 through 1750 2/0 4/0
Over 1100 Over 1750 3/0 250
 
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