Any codes issue here?

[anbm]

See attached image for sketch of elec. one line diagram, does anyone see any code issue?
I.e. using new 400A services (both normal and generator power) to power an existing 1,000A panel with 1,000A main breaker because
max. demand load of the panel is only 210A. No need to comply with coordination study in this case? Thank you.

 

[HarrySlother]

Coordination study isn't required for an optional standby system. Feeding the 1000A system with 400A is fine, as long as the inspector buys off on your demand load. See 220.87

 

[anbm]

Coordination study isn't required for an optional standby system. Feeding the 1000A system with 400A is fine, as long as the inspector buys off on your demand load. See 220.87

400A wires land to 1,000A breaker in downstream panel is not an issue?

 

[HarrySlother]

You'll have to check the breaker for it's specific lugs and compare it to the wire you're using.

I'd think you could safely use 500K Copper with a 1000A breaker but of course, double check that with your specific breaker.

 

[anbm]

You'll have to check the breaker for it's specific lugs and compare it to the wire you're using.

I'd think you could safely use 500K Copper with a 1000A breaker but of course, double check that with your specific breaker.

I meant code issue, small wire amp. vs larger breaker amp. it ties to…

 

[HarrySlother]

Oh gotcha. That’s also not an issue here because the wire is properly protected upstream