Service upgrade with disconnects???

[JHodges]

I am adding a garage and upgrading the sevice to 400 amps. I have a new 400 amp meter socket. from there I plan to run (2)- 3 conductor se cable via conduit to 2 seperate 200 amp main breaker disconnects in rain proof enclosures on the outside of my house @ 2 feet from meter. One of these will feed the existing main panel and the other will eventually feed a new panel once I get the structure dried in. I am doing things this way because by the grace of someone I am not being charged to run new sevice cable to the house, @ 2000.00 dollars worth. My question is once I hit the disconnect do I ground there and bond them, and then feed the panels with 4 wire and keep all seperate or do I run 3 wire to the panels and then ground and bond at that point.

I am using the existing panel that is currrently bonded and it is inside and @15 feet from where the disconnect will be outside.

I am John and I am a general contractor but this is my house and I am doing the work to keep costs down. I asked a friend who is an electrician but can be a flake. I read the threads and thoroughly confused myself. He said 3 wire from the disconnects and ground and bond the panels with no ground in the disconnects (waterproof main breaker boxes) Is he correct in what he told me??? Both panels will have there own main (redundant but will help get it done now to save big$$$$

[Jim Katen]

I am adding a garage and upgrading the sevice to 400 amps. I have a new 400 amp meter socket. from there I plan to run (2)- 3 conductor se cable via conduit to 2 seperate 200 amp main breaker disconnects in rain proof enclosures on the outside of my house @ 2 feet from meter. One of these will feed the existing main panel and the other will eventually feed a new panel once I get the structure dried in. I am doing things this way because by the grace of someone I am not being charged to run new sevice cable to the house, @ 2000.00 dollars worth. My question is once I hit the disconnect do I ground there and bond them, and then feed the panels with 4 wire and keep all seperate

Yes, that's what you do.

or do I run 3 wire to the panels and then ground and bond at that point.

No. The grounding electrode conductor has to connect to the neutral at or before the disconnect (250.24(A)(1))and the neutrals have to be separate from the equipment grounds after the disconnect (250.24(A)(5) & 250.142(B) & 408.40)

I am using the existing panel that is currrently bonded and it is inside and @15 feet from where the disconnect will be outside.

I am John and I am a general contractor but this is my house and I am doing the work to keep costs down. I asked a friend who is an electrician but can be a flake. I read the threads and thoroughly confused myself. He said 3 wire from the disconnects and ground and bond the panels with no ground in the disconnects (waterproof main breaker boxes) Is he correct in what he told me???

I believe he's wrong. If you're unsure, ask him to cite the code section that allows what he describes.

Both panels will have there own main (redundant but will help get it done now to save big$$$$

It might be redundant, but it will be convenient and make for a better installation.

- Jim Katen, Oregon

[JHodges]

Thanks for the info. I expect to learn a lot and this site is a great reference!

[Les]

John,

Jim K is right, as usual.

I like your tag line! I knew a pipefitter that used that phrase everyday.

[JHodges]

Jim hopefully you can confirm for me. The guy who sold me the wire for the run from the meter to the shut off sold me 4/0-4/0-2/0 URD.I wanted 4/0-4/0-4/0 but didn't realize the 2/0 conductor till I got home, but I believe the 2/0 is adequate neutral for the 200 amp legs is this correct. Thanks for the feed back. John

[Jim Katen]

Jim hopefully you can confirm for me. The guy who sold me the wire for the run from the meter to the shut off sold me 4/0-4/0-2/0 URD.I wanted 4/0-4/0-4/0 but didn't realize the 2/0 conductor till I got home, but I believe the 2/0 is adequate neutral for the 200 amp legs is this correct. Thanks for the feed back. John

It's probably fine. You're allowed to size the neutral service conductor to match the maximum calculated load between the neutral and one of the hot conductors. (220.61)

When making that calculation, you're allowed to reduce some of the loads for certain appliances so that calculated load often comes out quite low. The 2/0 wire will probably never see anything close to its maximum ampacity.

Of course, the neutral service conductor can never be smaller than the required size of the grounding electrode conductor. (250.24©(1))

-Jim Katen, Oregon