Wiring for my welder and compressor?

[TAftw]

I posted a thread a while back about wiring my garage for a welder. Well I have the welder now. It's a Millermatic 35. I am confused as to what gauge wire and size breaker I will need.

The specs are on page 19 of the manual: http://www.millerwelds.com/om/o1301q_mil.pdf

Forgive the stupid questions, I'm a little ignorant when it comes to electrical.

Page 29 shows the wiring specs.

 

[theoldwizard1]

On page 29 it says

All models are equipped with a three conductor power cable. Models requiring 200 or 230 volts input are equipped with a three prong polarized plug and wall receptacle.

I'm assuming you are installing this in your home shop/garage so you likely have 220-240V single phase power.

1. Look carefully at the power cord and find out what the wire size is. It should be molded into the cord.
2. What does the plug/receptacle look like. Reference this chart

Based on the chart in the book, you need a 35-40A breaker and a minimum 10 gauge wire. If your duty cycle in low, start with a 35A breaker. Depending how far you are from the main panel box, 8 gauge may be a better choice.

 

[TAftw]

I am pretty far from the main panel. The garage is on the other side of the house, and where the wire is going is in the opposite corner of the structure. So it's about as far away as it could be.

Should I go with 8 gauge wire and a 40 amp breaker then? Is this the sort of thing where it's better to overbuild, or does it have to be matched to the situation?

 

[southern iron]

i had one of these machines before i think mine was a '78 miller 35, awesome welder for sure i think i put a 50 amp in my panel . hard to find consumables for though , i think thats why i got rid of it and bought the miller 252, i still think the 35 had a nicer arc though

 

[TAftw]

So if I run 8 gauge wire, would I have a 50 amp breaker?

 

[ibedayank]

What does the graph on page 29 of the pdf file tell you to use?
over 50 feet from fusepanel to welder outlet i personaly would use the next bigger gauge wire. In this case being miller calls for 10gauge i would use 8. 35amp slow blow/trip breaker. miller calls for the 35 so use it.



That being said by the questions you posted i doubt you have the skills to do the work correctly. Voltage at that amparage can KILL you. Please hire a pro to have it done.

 

[TAftw]

So to be sure, if it's over 50 feet of wire, which it will be, I should be using 8 gauge, but I will still have a 35a breaker?

I am running the wire myself, and having my electrician hook everything up. He didn't give me any specs as to what I should be running for wire though, which is why I'm asking here.

 

[Aceman]

If there isn't a possibility of going to a larger welder, I'd run 10-2 on a 2 pole 30 amp breaker. There's no point in upsizing wire, there won't be hardly any voltage drop at 50 feet on a 240v circuit. 50 feet is peanuts.

 

[theoldwizard1]

So to be sure, if it's over 50 feet of wire, which it will be, I should be using 8 gauge, but I will still have a 35a breaker?

I am not an electrician (but I pretend I am one at times), but that is what I would use. This the "safe" half of the "Better safe than sorry" statement.

A bigger breaker will only mean that the wire can get hotter (from internal voltage drop) and possibly cause a fire, before the the breaker trips.

 

[TAftw]

Alright, I like the sound of "better safe than sorry". 8 gauge wire and a 35A breaker it is. I believe the run is about 50-60 feet the last time I measured it. When I go home I will measure again and double check.

There is not a very high chance of getting another welder. I have a Lincoln tombstone also, I actually forgot about it and I will have to pull the specs for that also.