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Old 06-04-2011, 07:47 AM   #16
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How to install a 100 Amp subpanel


FWIW...By code, you wouldn't be able to use a 500' roll of all black #6 for all 4 of the needed wires in conduit. Only #4 and larger can be re-colored. With #6, you could use a 250' roll, cut in half for the 'hot' legs, then the neutral would have to be a separate #6 w/white insulation, and the ground be green insulation or bare.

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Old 06-04-2011, 10:07 AM   #17
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How to install a 100 Amp subpanel


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Old 06-04-2011, 10:34 AM   #18
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How to install a 100 Amp subpanel


Hello Missouri Bound, I again apprecaite your support to my project. I agree with the conduit protection also, that was my original thought. Maybe I should go with the THHN in a # 4 to allow future upgrades? I really do doubt the need however. I also thought that the 6-3 NM-B would be easier for me to work with. It is all together and color coded. I assume the 125 foot run with the 6-3 will be okay and not too long? I guess the reason that I am considering the 100 amp subpanel is to allow me the 10 circuits that I am looking for. I believe that each of the 10 circuits will have plenty of power for each curcuit with the little draw that will actually happen. Installing the double pole 60 amp breaker at the main panel will allow me to run the smaller feeder wire and should give me plenty of power in the barn. Right now the entire barn circuit, one circuit, is extended from the kitchen. Can not run the table saw without a 100 foot heavy duty extention cord. It was a wonderful idea to draw up the actual power needs to see what I actually need. Thanks again and looking for any other advice that is out there.
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Old 06-05-2011, 06:08 AM   #19
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How to install a 100 Amp subpanel


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Originally Posted by SD515 View Post
FWIW...By code, you wouldn't be able to use a 500' roll of all black #6 for all 4 of the needed wires in conduit. Only #4 and larger can be re-colored. With #6, you could use a 250' roll, cut in half for the 'hot' legs, then the neutral would have to be a separate #6 w/white insulation, and the ground be green insulation or bare.
Er... In the context of my project, is this going to be an issue since I pulled 3 conductors of black 1/0 XHWN and a bare copper ground? I had thought that the ground was the only one you couldn't recolor... My inspector hasn't said anything about it yet and he has actually looked at the wires.

If you could please let me know what section of code this is from?

I see 250.119 where this is the case for recoloring the equipment ground, it basicly states you are not allowed to recolor equipment ground of AWG 6 or larger... For the grounded conductor, 210.6(B)(3) allows sizes larger than 6 AWG "At the time of installation, by a distinctive white or gray marking at its terminations. This marking shall encircle the conductor or insulation."

If I misunderstood anything let me know, I am after all a lay person and I know that my knowledge of code is imperfect, so I could be wrong and would appreciate some verification or correction.
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Old 06-05-2011, 12:25 PM   #20
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How to install a 100 Amp subpanel


210.5 Identification for Branch Circuits/215.12 Identification for Feeders
(A) Grounded Conductor: refers to 200.6
(B) Equipment Grounding Conductor: refers to 250.119
(C) Ungrounded Conductors: No other reference.

Be careful to read these sections carefully. These are often mis-read.
Key words are ‘Sizes 6 AWG or smaller’ and ‘Larger than 6 AWG’

I do wish the code would state #4 and larger, instead of ‘larger than 6’

If you pulled 3- 1/0’s, you can re-color one of them white to be your neutral. (200.6 (B))
An insulated conductor #4 or larger can be re-colored to be used as an EGC. (250.119)
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Last edited by SD515; 06-05-2011 at 12:28 PM. Reason: added 215.12 reference
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Old 06-05-2011, 01:42 PM   #21
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How to install a 100 Amp subpanel


Speaking of code....Is it code allowed to do as I am planning to use a 60 amp double pole breaker at my main panel to feed the 100 amp subpanel? I plan to use 6/3 NM - B as my feeder cable, but it looks like 6-gauge wire is for 50 amps? While I am asking more questions, I plan to run 14-2 NM cable to my 15 amp circuits using a 15 amp breaker in the sub-panel and 15 amp rated receptacles. For the 20 amp circuits I plan to use 12-2 NM cable with 20 amp breakers and 20 amp receptacles? Also I plan to use GFI receptacles in the barn, however, no water is near. Should I use regular receptacles or is GFI the correct way to go? Do all receptacles in a GFI circuit have to be GFI receptacles, or just the first in the circuit? Sorry for the questions, remember I am only a DIY Homeowner. I once again appreciate any information that you can send my way and thanks for taking the time to be involved in my project.
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Old 06-05-2011, 01:49 PM   #22
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How to install a 100 Amp subpanel


I would assume that a barn is treated the same way a garage is treated, as a wet location, because like a garage there is the potential for wet equipment to be driven into it. GFCI protection is required on all receps in a garage (as well as tamper resistant) and thus I'd assume it applies to the barn as well.

20 amp circuit with 12 ga wire and 20 amp breaker can use 15 amp duplex receptacles because it's rated for 15 amps for each individual plug so the whole duplex receptacle can handle 20 amps.

Now if was a single receptacle it would be required to be 20 amps.

Looking at table 310.16, 6 ga. copper is good at 75 degrees C to 65 amps so it should be fine for a 60 amp circuit. Were you looking at the aluminum column?
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Old 06-05-2011, 01:56 PM   #23
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How to install a 100 Amp subpanel


The table I have shows #6 good for 75 amps. THHN that is,
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Old 06-05-2011, 03:22 PM   #24
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How to install a 100 Amp subpanel


Thanks again. I am actually looking at a book for the ampacity. I assume that you are more likely to be correct on your numbers. The cable that I am looking at from Home Depot is Cerrowire 6/3 NM-B. It has 3 #6 copper wires and 1 # 10 copper ground. I assume that THHN is rated the same if this wire is copper also? So it should handle the 60 amp sub-panel. I will install all GFI plugs because of the wet possibility. Can I use 20 amp duplex receptacles in the 20 amp circuits if I would like to? I assume that 15 amp would be cheaper, but 20 amp would make sure that it can handle the possible load? I will use 20 amp breakers and 12-2 wire to feed the circuits. Can I choose to use 20 amp duplex receptacles? Thanks to WillK and Missouri Bound for responding, I appreciare it.
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Old 06-05-2011, 03:34 PM   #25
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How to install a 100 Amp subpanel


20A receptacles are allowable if you want to spend the extra money.
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Old 06-05-2011, 07:56 PM   #26
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How to install a 100 Amp subpanel


I just looked at the specifications listed on the Home Depot web site for the 6/3 NM-B feeder cable that I am thinking of using for the subpanel and it says the allowable ampacities is 55 amps for the wire. Does this mean it is too small for my project? I found a chart for # 6 gauge ampacity and it said that at 60 degrees C it is rated for 55 amps, at 75 degrees C rated for 65 amps, and at 90 degrees C rated for 75 amps. Looks like the THHN wire has a higher amp capacity? Maybe because it is not enclosed? Please let me know your thoughts on the 6/3 and the 60 amp double pole breaker feeding the subpanel. Maybe I should use a 50 amp double pole breaker, if there is such a thing? Or larger wire, # 4? Thanks
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Old 06-05-2011, 08:04 PM   #27
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How to install a 100 Amp subpanel


#6 Cu THHN can be derated off the 90* column, but most likely would fall into the 75* column at best. Rarely are you going to find terminals rated for 90*, and both terminals at each end of the wire would have to be rated 90* to be able to use the 90* column.

6/3 NM cable used as a feeder would put it in the 60* column at 55 amps, but is allowed to be protected by a 60A breaker.

Yes, the barn would require GFCI protected receptacles, if not intended to be habitable (which most likely is not).
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Old 06-05-2011, 08:20 PM   #28
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How to install a 100 Amp subpanel


Thanks SD515, I appreciate the support. Thanks for explaining the ampacity ratings, now it makes more sense. I had assumed that the 60 degrees C column was the one for me. Sounds like the 6/3 NM-B cable will work for me. I will use the double pole 60 amp breaker at the main panel. Is it safe and okay to install a 100 amp subpanel with this setup? I did do a load evaulation and came up with 57.7 amps needed at full capacity, which will never happen. The 60 amps should be plenty of power. The 100 amp subpanel will give me the 10 circuits needed. Please verify if my thinking is correct on this one, I want to be safe. Thanks again.
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Old 06-05-2011, 08:27 PM   #29
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How to install a 100 Amp subpanel


The 100 amp rating of the panel is the maximum it can safely carry. Anthing less, like your 60 amp supply is fine.

Are you planning on the 6-3 Nm being outside?
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Old 06-05-2011, 08:48 PM   #30
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Hi Jim, thanks for responding. The 6/3 NM -B cable will all be inside. The main panel is in my basement and the 6/3 cable will run on the floor joists in my cellar, then under the pantry(which is a crawlspace). Once in the woodshed and barn, the cable will be run overhead to keep away from animals that might want to munch on. I am thinking about using a conduit under the pantry crawlspace, like 12-15 feet of the run, to further protect the expensive 6/3 cable. There is about 125 feet between my main panel and sub-panel and ALL indoors. Thanks to everyone once again.

PS Thanks for the info on the 60 amp breaker feeding the 100 amp sub-panel. Makes me feel better with all this great advice.

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