breaker feeding sub question...

[mayjong]

hey all- been a long while

i thought i had the answer to this one, (but i made the mistake of opening the book to check my answer!) 2008 NEC-
200A panel. contractor wants to use a 20A breaker (with 8 gauge wire)to power a 40A subpanel (for lights and plugs in a workshop)
my question is about the 20A, "feeding" a 40A panel.
is this a code compliant install? section?
thanks!

 

[pete m.]

It is code compliant as long as the calculated load does not exceed 20 amps. The sub-panel will be protected in accordance with 408.36.

I would question if the 20 amp breaker is listed to terminate 8awg wire.

Pete

 

[Dennis Alwon]

Why would the contractor want to use a 20 amp breaker if the wire is good for 40 amps. Sounds ridiculous. The dp 40 costs the same as dp 20's. Also if you use a dp 20 then you must upsize the egc to #8 also.-- article 250.122(B)