Sub panel wire sizing.

[mike93lx]

XHHW-2 is legal to pass through interiors in conduit correct?

Yep, good to go.

Make sure the conduit is fully installed and glued up (if using pvc) before installing any wire. The glue will ruin the wire and its a code violation

 

[6togo]

Will do! Trying to find the best price of conduit now crazy how much that and wire went up!

 

[mike93lx]

Will do! Trying to find the best price of conduit now crazy how much that and wire went up!

I have generally found HD to be the best price, but I got a good deal on a bunch of 3/4 conduit from a local electrical supplier last year. Looked like old stock, but they were half the cost of HD. Wire was cheapest online

 

[6togo]

Yea seems like Lowes is a few bucks cheaper on the conduit plus I get contractor pricing which is 5% more. I'm going to hit my buddy up and see if he can get any better pricing from the local supply houses not likely but worth a shot. Thanks for all the help!

 

[6togo]

Question so the main breaker feeding the first sub panel is 100amp like I stated in the beginning which is not code. If I swap that for the correct 90amp breaker does it matter if the other two panels have 100amp mains?

 

[mike93lx]

Question so the main breaker feeding the first sub panel is 100amp like I stated in the beginning which is not code. If I swap that for the correct 90amp breaker does it matter if the other two panels have 100amp mains?

No. The breaker in the sub is just a disconnect. You could use a 200a if you wanted.

Is the breaker feeding it that matter since that protects the wire between the panels.

 

[6togo]

So the first 90 amp breaker in the main panel trumps the other two 100amp disconnects in the subs and makes it code compliant?

 

[mike93lx]

So the first 90 amp breaker in the main panel trumps the other two 100amp disconnects in the subs and makes it code compliant?

The 90 in the main protects the wire to the sub. The size of the breaker in the sub fed by that is irrelevant as it is just a disconnect. Practically, you want it at least the same size as the 90a so you get access to the full 90a.

If that sub is feeding another sub with #2, the breaker in sub #1 connected to that feeder has to be 90a or smaller. Sub #2 can have any size main in it, but again, you would be best to have it be at least 90a

 

[6togo]

Ok so main to sub #1 should be a 90amp then Sub #1 to Sub #2 should be a 90 amp then sub #2 can have the 100amp? Seems to me having the first 90amp breaker in the main limits the other two anyways so the breakers downstream are disconnects at that point.

 

[mike93lx]

Ok so main to sub #1 should be a 90amp then Sub #1 to Sub #2 should be a 90 amp then sub #2 can have the 100amp? Seems to me having the first 90amp breaker in the main limits the other two anyways so the breakers downstream are disconnects at that point.

Yes