View Full Version : How long can I run 4/0 200 amp circuit
felicesnow
Feb 11, 2011, 06:39 AM
Power company said I could run 4/0 wire 225 feet from my meter/main breaker panel to a sub-panel in my new home. Electricans that I work with said it would be too much voltage drop. What should I do?
jcaron2
Feb 11, 2011, 07:46 AM
I was under the impression that 5% voltage drop was at the upper end of the acceptable limit. With 4/0 aluminum wire, at a full load 0f 200A, I think you're only going to drop around 3.7%, so I would agree with the power company.
That being said, please bear in mind that I'm not an expert. Hopefully tkrussell will chime in. He's the real expert with this stuff.
felicesnow
Feb 11, 2011, 07:56 AM
Thank you. Im like you ykrussell seems to know his stuff.
tkrussell
Feb 11, 2011, 10:27 AM
The max recommeded voltage drop for both feeder and branch circuit is 5%.
Typically, 3% is applied to the feeder, and 2 % to the branch circuit.
So, this feeder should be sized to keep the Vd to 3% or less.
The important variable is the load amperage. A 200 Amp service should not be loaded more that 80%, or 160 Amps.
If the load is to be assumed to be 160 amps, then #250 MCM aluminum is required.