Voltage drop conductor size

[JJWalecka]

Hypothetical....#12 from panel to JB.....then #10 from JB to load.....seems ass backwards but would it still assist with voltage drop?

Ideally it would be #10 then #12.

 

[ActionDave]

Either way works. A circuit is a closed loop so it doesn't matter where you put the bigger wire.

 

[texie]

It makes no difference. It is not unusual to have, say, a 20 amp circuit with way oversized conductor in the middle and #12 at each end.

 

[synchro]

As has been mentioned, it makes no difference which order you have the two different conductor sizes with a single load.
Now if you have multiple runs to loads that branch out from the JB, then it's more efficient to put the larger conductor before the JB because it will have the highest current.

 

[retirede]

It depends on where the j-box is located. You probably want the big wire on the long side.

It wouldn’t make sense to run 200’ of 12 to the j-box and 20’ of 10 on to the load.

 

[JJWalecka]

Thank you