Hello,

Hoping someone here can point me in the proper direction. - I've read through countless articles online as well as about a dozen threads here on this board.

I specified the General Contractor run a 100 Amp service to my detached shop. - I just checked the installation and he has 3 wire #6 copper free running through the attic. - The run will be about 200 feet total. Most websites indicate he needs to be using #4 at a minimum, with some recommending #2 due to the length of the run. - Can anyone point me to the NEC code or page in the book that specifies exactly what is correct so I can show it to him when we meet ?

Thanks so much in advance.

Just tell him you know for a fact that #6cu is not good for a 100A feeder. If he tells you it is then fire him and find an honest contractor.
Maybe it was an honest mistake?

Just out of curiosity, Is there a 100 amp breaker currently in the main panel feeding the service to your shop?

My first question to the GC would be, where is the plan you submitted and the approved permit.

From the git-go there are severe violations. For example, A feeder from the main service panelboard to another panelboard requires a four (4) conductor cable.

Table 310.16 must be used for the base conductor size. Then, although not a requirement of the NEC, voltage drop should be calculated. For 100 amps, copper using insulation listed for 75 C, #3 AWG conductors are needed. However,for a 200' run you need to use #1 AWG conductors.

There are a lot more codes that deal with the remote bldg so my suggestion is to have a licensed electrician look at your plan before your GC does anything.

Also whoever you decide on to do the work, make sure they pull the electrical permit in their name.

Don, Thanks for the reply. It's in an unincorporated area so there are no permits required.

I looked at the 310.16 code page and it surely does look like #3 should be what he uses at a minimum, #2, or #1 even based on the voltage drop.

I'll get on the contractor to get this fixed.

Thanks !

Kyle, I do not have the building put up yet, but yes, there will be a 100 amp main panel when it is done.

Stan, I'm with you on that logic, but the GC is overseeing everything. We just got to get the electrician straightened out. :)