I was asked by a future customer to give him a bid on his new house. He wants 2 200 amp panels. He's gonna have a detached garage, and he wants a panel in there too. I'm assuming a 100 amp one. I'm thinking installing outside disconnects, even tho it will cost a little bit more, since it'll make the job a lot easier to feed the detached garage in contrast to having a back to back service and then feed the garage from inside don't you think?. this is my first one with detached garage. . .
How do you all usually do it? i could have one panel back to back and another with a disconnect but i think it'll look silly.
Thanks.
You have options that code will allow that will keep you to two disconnects on the house or no disconnects and just main breaker panels if the two 200 amp panels are located next to each other or one disconnect located next to one 200 amp main breaker panel, but it will depend upon calculated load as kwired said.
First you will need a 320 meter with triple load lugs the detached garage can run from the load side of the meter right back into the ground with just the two hots and neutral over to the garage then hit a main breaker panel in the garage which you just treat like a service which code requires us to do anyways except the separating of grounds and neutral as you would if you ran a feeder and had a separate EGC which you would not need in the above since these are service conductors.
And you don't need a disconnect at the house because you have not entered a building yet (which you do at the garage) so that not only eliminates the EGC it also eliminates an extra disconnect only requiring one at the garage which can be a main breaker panel.
Second you need to keep 230.72 in mind for the disconnecting means anytime you do a split service on a single building, so because of this you can either have two 200 amp disconnects out side and two main lug only panels anywhere inside, or two main breaker panels just inside but they have to be grouped, or one main breaker panel inside and a disconnect next to it so that one panel can be located elsewhere closer to loads, so you have options to chose from and some of these can be money saving for you or the owner.
The detached garage trick is allowed by two things, the exception #3 in 230.40 and the fact the wording of 230.70 only requires a disconnect for conductors "in a building" and running from the load side of the meter base into the ground is not "in a building" and is the whole reason for the exception #3 to 230.40 also a meter is just a wide place in the service entrance conductors and is not a disconnect so the wires from the load side are still service entrance conductors and are treated as such and because of this the neutral is the EGC so the main breaker panel in the detached garage is service equipment and bonding (main bonding jumper) is required just like at the house.
not many know or understand this allowance but it is right there in the NEC as I have pointed out.
I hope this gives you some better ideas to allow some savings for this service.