Voltage Drop

[smarteng]

I have a 600 ft circuit carrying 15 amp current between MS and Load. So per voltage drop calcs, I require to use 1 AWG to limit voltage drop below 3%. Circuit Enters in a control panel at 450 ft, goes through a 20 amp CB and continues to the load. So now I have two circuit From MS to control Panel 450 ft and control Panel to load 150ft. Should I use 1 AWG wire for entire run as per my calculations. Or do I need to calculate Voltage drop for two different circuit. If I calculate voltage drop for two circuit I will be able to use 2 AWG and 6 AWG. Is there any NEC restriction related to it. Please advise. Thank you so much.

 

[JoeStillman]

If there is no other load on your control panel and you've sized your #2/#6 wires for 3% each, then that is a 6% total voltage drop. In this case, use the #1 all the way.

But if there are other loads on the control panel, there's more math to do. Different VD's accumulate as loads are added along the circuit.

 

[smarteng]

If there is no other load on your control panel and you've sized your #2/#6 wires for 3% each, then that is a 6% total voltage drop. In this case, use the #1 all the way.

But if there are other loads on the control panel, there's more math to do. Different VD's accumulate as loads are added along the circuit.

Thank you so much sir.

 

[kingpb]

or if a transformer is involved.