400 Amp Residential at remote Garage

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ponder22

New User
Location
Los Angeles, CA
Occupation
Mechanical Engineer
The problem, SoCal, NEC 2017 here. The home is all electrical with 2 A/C units, double oven, car charger, dryer etc.. looking for 400amps at the house. The detached garage ("Shop") is closest to the pole and has 80A of solar on the roof and looking for 100Amp minimum panel for it.

The homeowner doesn't like the aesthetic of adding the meter to the house and running power back to feed the shop subpanel. He also wants to add a backup generator to the side of the shop.

Assuming the meter is at the shop and two, 200Amp subpanels are fed to the house (One 200amp would be a sub off of a shop 200amp panel). Is there a configuration to satisfy NEC 2017 225.30?

I don't think a CT meter is an option but it may be worth asking.
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
It's a long shot but if you have a generator at the shop supplying one of the feeders back to the house the AHJ might allow it under 225.30(A)(4) especially since the "one feeder only" rule is relaxes in Codes later than the 2017.
 
230.40 exception #3 may be handy here, and save you some electrical equipment. Set a CT can or class 320 base and come out of it with a set of service conductors to the house to either 400 amp panel or hit a box and tap it to two 200's. Then come out of the CT can or 320 base with another set to the garage to another service panel. Size that garage print panel appropriately to accommodate a load side connection for the solar, or bring another set out of the meter for a line side connection or another 230.40 exception 2 panel.
 
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