[NewHomeOwner13]

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.

[stanfortyman]

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?

[Kyle_in_rure]

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

[donf]

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.

[NewHomeOwner13]

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 !

[NewHomeOwner13]

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

[NewHomeOwner13]

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