Adding Service to a House


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Old 05-22-14, 04:15 PM
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Adding Service to a House

I purchased a lot 3 years ago and built a pole barn and added 200 amp service. The service drop is overhead to the barn, then to the meter, then inside to a convertible Square D load center, which is set up with a 200 amp main breaker.

Existing configuration: Transformer --- ovrhd svc lateral --- meter base --- load center

I'm now building a home next to the barn. The problem is the overhead service comes into the barn on the opposite side the house will be on, and I don't want to have another electric company service drop/meter. So how can I get power from the existing meter base (customer side) and run power to the load center in the barn and a new load center in the house? The 4/0 run from the meter base, a disconnect, or the old load center to the house will need to be underground.

Can I enter an enclosure that splits the service entrance to both buildings? Should I run a new service conductor from the meter base (underground) to the house and then re-configure the barn load center as a sub-panel? If I run underground, can I trench through the barn (I don't have a floor in yet) or do I need to go around from outside the building. The barn is 36' wide and the house is another 24' away on the opposite wall (from the service entrance), so trenching straight across would be 60'; going around would be 125+'.

If I go underground, are there any specifics on depth? I have specifications for an underground service lateral, but the power company tells me that there are different rules for power to the meter and the customer side (post meter).

Thanks.
 

Last edited by kshomper; 05-22-14 at 06:51 PM.
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Old 05-22-14, 07:02 PM
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It sounds like a stretch to me. Why don't you want another drop from the power company?
 
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Old 05-22-14, 08:05 PM
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What is the calculated load of the house?

If the existing 200 amp service is big enough for both house and barn, I see two options.

1.) Feed house from existing 200 amp panel in barn.

2.) Install 200 amp disconnject adjacent to meter and feed disconnect with 4/0 wiring (3-wire). Feed from disconnect with 4/0 into a NEMA 3R J-box with your 4/0 wiring (4-wire). Split your wiring in the J-box and run 4/0 wiring (4-wire) to both the existing barn panel and the new house panel. Both panels become subpanels and will require neutrals be isolated from ground and a ground bar in each. The neutral will be grounded in the new 200 amp disconnect (fusible or breaker disconnect). The house will require a ground rod, maybe two depending on local AHJ's decision. The neutrals and grounds will have to be separated at the barn panel and the neutral bond to the box will have to be broken.
 
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Old 05-24-14, 07:28 PM
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Makes sense, particularly when you describe the two panels as sub-panels. How do you split the 4/0 wire in the j-box, as the wires are quite thick, is there a three way coupler? Are all four wires 4/0 or do I use 4/0-4/0-4/0-2/0? Which one is the 2/0?

The house will be a three bedroom with a basement. The house is all electric, so water heater, stove, dryer, and furnace will be electric. I'll have a workshop in the basement and at some point, I'll finish the basement and have a third bath and small kitchen and at least one bedroom down there. So, I'm not sure 100 amp service to the house will be sufficient.

I don't want another drop from the electric company for two reasons: 1) the barn is on commercial service because I didn't have a residence when I established service. If I have it on separate service it will stay commercial which is more expensive. 2) an underground run from the transformer to the house (around the barn) will be over 225'. That's a lot of expense, I'm looking to avoid.

I did think of one other option. After a disconnect next to the meter, what if I run 4/0 (3 wire) to the house, then bring the right sized wire back the barn for a 100 amp sub panel? Since I don't have very many circuits in the barn yet (4), I could move the barn's panel to the opposite wall (near the house) and then it would just be a 25' run (plus vertical), back to the barn.

This seems the most economical. If I did this, would I be allowed to share the trench for the main run into the house and back to the barn? What size wire would I use for the run back? I can check this forum for info on wiring a sub-panel. Thanks.

By the way, if code allows, Could I run the 4/0 wire inside the barn, along the underside of the loft, as my existing meter and panel are right below the edge and then I could come down into the ground and trench the short distance 25' to the house. That way the wire would be accessible after I put a floor in the barn without ripping it up.
 

Last edited by kshomper; 05-24-14 at 08:05 PM.
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Old 05-31-14, 05:19 PM
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Splitting 4/0 Wire

So the recommendation to split the service entrance in a j-box it likely the direction I'll go. My question is what do I use to do this, and can someone provide a link to a part? I've searched and I'm not finding anything that would split a 4/0 wire to two other 4/0 wires.
 
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Old 05-31-14, 05:35 PM
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Polaris makes 3 hole connectors in that size range.
 
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Old 06-01-14, 07:20 AM
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We use THHN / THWN almost exclusively . Having said that , we use 3/0 THHN copper for 200 amp commercial feeders .

What little residential we do , we use 2/0 THHN copper for residential .

Why are you all recommending 4/0 ? Are you speaking of Al wire ? Or are you speaking of 4/0 copper for voltage drop ?

Thanks ,
Wyr
God bless
 
 

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