4/0 AL SER 200amp dwelling feeder one of several in 600 amp service

[flatlander]

Hello looking for clarification.

Have a new mcmansion with a 600 a service.
Can I use 4/0 AL SER with 200a breaker for one of the feeders from the main panel that only has sub feeds no branch breakers.
The feeder will run through interior walls only that might have insulation for sound.

Does it work at 200 amp breaker?

 

[hmspe]

What year is the adopted NEC?

 

[flatlander]

2014 NEC or 2016 CEC

 

[flatlander]

Please any help?

 

[kwired]

4/0 aluminum has a 75C ampacity of 180. You can use it for no more than a 180 amp load and protect it with next size up overcurrent device of 200 amps.

IF you have a situation where you must treat it as 60C conductor (some conditions in past code cycles) then it only has an ampacity of 150 amps, and that is a standard overcurrent device so it can't be protected at more than that either.

 

[flatlander]

So I can calculate only to 180 . I guess that will work.

Oh and thanks

 

[kwired]

So I can calculate only to 180 . I guess that will work.

Oh and thanks

If it is supplying the entire load of a dwelling unit it can be used to 200 amps per 310.15(B)(6) (before any adjustments if needed).

 

[flatlander]

It's a one feeder of several others that feed several different panels.
No panel over 200 amp

 

[kwired]

It's a one feeder of several others that feed several different panels.
No panel over 200 amp

You said in OP it is a mcmansion, I guess there is some chance of having a feeder that supplies a section that could qualify as an individual dwelling unit, if so 310.15(B)(6) can be used. But the feeder would need to supply that individual dwelling section only plus it must supply the entire load of said dwelling to be able to use this ampacity allowance.

 

[flatlander]

Interesting ,
Would not apply on this job though.

 

[kwired]

Interesting ,
Would not apply on this job though.

You still can run 4/0 protected at 200 amps if load calculation isn't more than 180 though. Exception be if you need to use SE cable at 60C for some reason.