400A Service from Shop to Home

[infinity]

They are under the understanding that your reference for next size up with be for brand circuits, not a service entrance conductor.

That is incorrect unless there is a local amendment to the NEC. The next size up rule can be applied to branch circuits, feeders, and service conductors. Around here a typical 200 amp service is usually #4/0 Al SE cable.

 

[don_resqcapt19]

They are under the understanding that your reference for next size up with be for brand circuits, not a service entrance conductor.

230.90(A) Exception #2 makes it clear that 240.4(B) applies to service conductors.

 

[bmaclaff]

Thanks everyone on the 4/0 vs 250 to the shop/detached garage, or whatever. Either way, it will be just a couple of feet down the wall from the meter to the disconnects.

My primary concern is the overall plan. Suemarkp and Electrofelon had similar options, with the last one having 4 service entrance cables attached to the meter base, 2 to the house, 2 just a couple of feet away for the shop. One commenter wondered about the disconnects being visible from the house. This latest idea would have 2 disconnects at the house and 2 at the shop.

 

[tortuga]

That is incorrect unless there is a local amendment to the NEC.

Its a funny thing in Oregon most licensed electricians are "Journeyman" electricians while they are licensed make any electrical installation they are technically not allowed to do load calculations and or "direct, supervise, or control the installation or alteration of an electrical service".
A General Supervising Electrician Is the only individual authorized to direct, supervise, or control the installation or alteration of an electrical service in this state.
See OAR 918-282-0140 (c)
Up north in WA state I believe its similar but called an "Electrical Administrator".
Since most residential service upgrade's are permitted 'over the counter' - no load calculation or electrical plans are required, submitted or reviewed thus technically no load calc.
And the work is often performed by a solo journeyman no supervising electrician on site.
Absent that calc or a person licensed to do one on site most inspectors presume the service load to be the main breaker rating, some may accept a phone call or email from the Supervising Electrician.
If a General Supervising Electrician or EE has performed a article 220 load calculation in the electrical plans the 4/0 should pass.

 

[infinity]

Absent that calc or a person licensed to do one on site most inspectors presume the service load to be the main breaker rating, some may accept a phone call or email from the Supervising Electrician.

I'm curious as the why anyone would make that assumption? If I have an existing 100 service that is being upgraded to a 200 amp the load shouldn't exceed 100 amps or slightly more in an extreme case. Certainly the existing load wouldn't be greater than the 180 amp rating of the #4/0 Al conductors.