#### Ivan Young

##### Member

- Location
- Simpsonville, South Carolina

I am new to this forum and I posted a question yesterday but did not get an answer. I am hoping taht some one here can help me.

I am a helper with an electrical company here in South Carolina. Two other helpers and myself are currently studying some Mike Holt DVD's to take our Journeyman exam in the next month or two. The question has to do with voltage drop and the sizing of wires.

Lets say you have a 220v, 30 amp, two hots and a ground (no neutral),50 feet from the panel, circuit that going to be on for five to six hours. This is a continuous load so it has to be multiplied by 125% which brings it up to 37.5 amps. Since there is no 37.5 amp breaker a 40 amp breaker would be used. The question that we would like to have answered is this. Do we use 30 amps or 40 amps in our calculations when figuring out the wire size? Some say that the 30 amps should be used because that is what the load is actually rated at. Some say use 40 amps to size the wires since the breaker is 40 amps and the wires must be sized to match the breaker.

What is the correct answer?

Thanks for your help in advance.

Ivan