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I am having a new shop built on Friday.The shop is located 250 feet from my power meter.

For a 240 volt 100 amp service in the shop, the online calculator says I need 2/0 AWG Aluminum or 1AWG copper.

I have underground service to my home and the wires leading form the meter run under the slab to the 200 amp panel in the bedroom closet. Running a wire from the panel in the house to the shop will not work as I cannot get the wires into the house. The meter also has separate wires running to a 100 amp service panel in the add on washroom. There is a separate conduit running to the meter box that feeds this portion of the house. The wires feeding the 100 amp service are too small for what I need at the shop. Plus I have the same issue getting the wires into this panel box as well.

What do I need to do to get the power run to my shop? Is there a way to tie 2/0 AWG into the meter? I am guessing the meter is already crowded since it has wiring for the 200 and 100 amp service running to it. I am guessing there will be no room to run additional wiring to it as is.

My service line to the shop will be under ground. What wire type should I use?

  • Here is a related question that might interest you. – JPhi1618 Apr 9 at 21:02
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    I take it you have a 200A service overall from your electric utility? Also, it sounds like both panels are improperly located to begin with, so it may be necessary to migrate things just to bring them up to Code within the house... – ThreePhaseEel Apr 9 at 23:27
  • Also, why is getting wires into the house such a major issue? – ThreePhaseEel Apr 9 at 23:27
  • Any chance of getting photos of the meter box, door open (not cover removed)? – Harper Apr 10 at 0:28
  • The house was built in 1982. I am not sure what the transformer is rated that feeds the house. The main breaker is rated 200 amps. The add on room which has a dryer and washer and lights has its own 100 amp panel. The 200 amp panel is not connected to it. The house is built on a slab with the conduit buried in the slab. Feeding additional wires into it would be a challenge. – grantr Apr 10 at 14:32
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Unfortunately this has quite a number of defects in it already, including a panel in a clothes closet, a panel in a bathroom, and 2 feeders (service laterals, really) to the same structure.

As far as splitting the laterals below the meter, that is just a matter of splicing space, and you will be able to resolve that with an additional box or gutter below or on the opposite side of the pole from the meter.

Normally this type of splitting calls for a main breaker at the meter, and then supply breakers to each lateral feeder that is not rated for the ampacity of the main breaker. (But still, dual feeders to the house would be problematic.) I am concerned Anyway, that is a good argument to up this outbuilding feeder from 2/0 to 4/0, because then you

Anyway, the upshot of all that is that you are already at 2/0. If you spend a bit more to take it to 4/0, then that wire would be legal at 200A.

  • So I am getting an electrician to wire in a feed through meter base with additional circuits. This will give me a 100 amp breaker to connect the SEC to my meter. For the SEC do I need to run triplex or quadplex to the sub panel in the shop? – grantr Apr 23 at 17:47
  • @grantr That's a hard question because it's really unclear to me where your service point is. Since I assume this type of installation is commonplace in your jurisdiction, your AHJ would be most well-briefed on what they accept. I for one would err on the side of either quadplex or an appropriate sized ground wire alongside the triplex, depending on price. – Harper Apr 23 at 19:53
  • Why does the sub panel need the ground tied back to the main panel? Is this for an extra safety measure? With a 3 wire feeder feeding a sub panel, the neutral would need to be bonded to the ground wire in the sub panel in order for the ground wires to have a return path back to the source. In this case you would not install a 2nd ground rod at the sub panel. – grantr Apr 23 at 20:50
  • When running a 4 wire feeder, a ground rod at the sub panel is ok since it is tied back to the ground rod at the main panel. – grantr Apr 23 at 20:50
  • @grantr 3 wire feeder is not a thing. 3 wire service is a thing. the question here is, where is your service point? also you will always instal ground rods at an outbuilding panel. – Harper Apr 23 at 21:43

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