Electrical wire size, what size to run?

[MyMopar]

2 questions regarding wire size.

1) For a 220 volt welder (Miller 175) what size wire should I run say for a 10' length? and what size breaker?

2) For a 7500 watt generator, what size wire should I run for that back to the panel?


The welder would be 2 hot and ground so that would be wire (size)/2 correct?

I know the generator is going to be 4 wire, 2 hot, neutral and ground, so it would be wire (size)/3 correct?

 

[TOMWELDS]

With a cord (like an extension cord), you include the ground :EX; 1 white 1 black 1green = 12/3, if 12 gauge.
With cable, (like romex or BX), you dont include the ground :EX; 1 white 1 black 1 bare = 12/2, if 12 gauge.

I dont own the 175 but i think miiler recommends a 30amp circuit. The machine comes with a 50amp 250volt plug. That's standard with most welders. Install 10/2 RX or BX in the wall. 30amp breaker 2pole, and a 6-50R receptacle (50amp 250 volt recep.).

 

[TOMWELDS]

With the 7500 watt generator, if you're making a quick cord for using on a jobsite or camping, #10 would be ok. If you're making a hookup to use during a black out, use 8/4 cord. 7500watts = 31.25 amps @240volts. technically that's for #8 wire.

 

[Fast Orange]

1) What is input amperage for welder? If 50A,use #6 AWG.
2) For 230V/7500W=33A-Use #8 AWG

Concerning # of conductors in different types of cables- X=wire AWG
X/2 romex= 1 white,1 black, 1 bare-MC cable is the same
Rubber cord-X/2= 1 white, 1 black-NO GROUND
X/4= 1 white, 1 black, 1 red, 1 green

George

Edit-You beat me to it,Tom-I gotta learn to type quicker.

 

[Stuart in MN]

The thing about welders is that the wire size depends on the duty cycle. The lower the duty cycle, the smaller the wire size. That's why a welder may have a 50 amp plug connected to wire that otherwise is only good for a 30 amp circuit. This is covered in article 630 of the NEC.

The owner's manuals for your welder and generator should have the factory recommendations for wiring. If you don't have copies you can probably find them online, I know Miller has the manual available on their website.

 

[TOMWELDS]

Sberry is the best one for info on duty cycles and the like.

 

[MyMopar]

Thanks, I was looking to confirm some info and now it is crystal clear.

 

[CraigFL]

I'm lazy so I just go to Home Depot and they tell me the wire size to run based on their wire(different wires have different current ratings for the same size). That way I don't have to look it up in the NEC. If I was using a standard 50A outlet, I would probably run 50A rated wire and a 50A breaker and mark it as such.

 

[79rallysport]

What I did when wiring my welder, I used 50A rated wire with a 30A breaker (the welder reqired a 30A circuit). This way, if for some reason I upgrade to a welder that requires a 50A circuit, all I have to do is switch out the breaker and the wire is already to go. FYI, the circuit was only about 3ft long but it was in the wall and can't be changed later.

 

[TOMWELDS]

That's the best way: #8 (50amp) and you can use any breaker up to 50amp.

 

[muddy]

I have a Miller 250 but I don't think the internals are alot different from your 175 at least I know the Miller 200 is about identical. Anyways, the input amps is what is important according to my electrician and 50 is the input for my 250......... Keith