electrician needed, wiring up a 220 volt welder

Uhh, I think then you'll be all baked.

How about wiring up an outlet in the garage that's solid wire instead of stranded?

I got lucky in the rent house I had, the dryer was just inside of the door into the house from the garage, problem was leaving the door open, so I did some redneck engineering. I wanted to make sure my wife didn't use the dryer while I welded, or was using my air compressor (6hp 60 gal. direct drive Craftsman 220v). I mounted a 1x4 to the garage side wall in the dryer nook, on that I had a 4x4 box with a 220v outlet that matched the dryer cord, out of that box ran the wiring that went back under the cabinet that was above the dryer and thru the wall out into the garage. I had also bought another dryer cord and wired it to the back of the plug along with the aformentioned wiring. This plug I plugged into the outlet behind the dryer and I plugged the dryer into this new outlet, so that took care of the dryer. I put another 1x4 on the garage side of the wall, this also was the corner that my compressor was in. I put another box out here that matched the plug on the Lincoln arc welder I had borrowed from my dad. I also ran another set of wires out of this box and hard wired the air compressor to it. Now if I wasn't working in the garage, the compressor was turned off and the dryer plugged in. If I was welding or needed the compressor, I unplugged the dryer, then my wife knew I was needing the 220 and not to plug it in. If I was working in the garage and left it plugged in, I wasn't welding or using the compressor. I made sure that when I welded, I turned the compressor off, so I only ever had one thing running on the circuit. Worked out pretty slick, unless I forgot to turn the compressor off and it blead off enough to kick on at 3 am. The whole damn house vibrated and I'd shoot up out of the bed at the opposite end of the house (only 875 sf so it wasn't that big). Only did that twice.

Where is you fuse box? If its in the garage, you could maybe add a circuit and put a outlet right below the box.

8 AWG = 3.2639 mm diameter, 8.367 mm^2 area
12 AWG = 2.05232 mm diameter, 3.308 mm^2 area

Tripling 12 AWG cable would be a little more area than the single 8AWG. How many amps does the welder draw at max pull? Say 40A, at a 50ft run, a 8 AWG cable has a voltage drop of 1.26V. 40A is about the max you'd wanna run through 8 AWG (at 100 ft I should note). At the same 40A for a 50ft run with 3 12 AWG cables, since they're in parallel they're total resistance is lower than any of the lone cables, the voltage drop would be 1.06. Each 12 AWG cable at 100ft can carry 30A. Assuming that the welder draws a similar amperage (as the amperage goes up the voltage drop would also go up, V=IR), IMO 3 12AWG would be fine.

BUT

A single 12 AWG ground, with triple 12 AWG hot and commons, is a BAD idea. You're ground aught to be the same size as the hot and common, if you have a short circuit situation you don't want to have a bottleneck at the ground. Just imagine if there was a short with NO resistance, it would be a ton of current trying to all cram down a single 12 AWG wire... Might be easier for it to go through your arm or something. You don't wanna skimp on the ground. Personally, IMO even 2 12 AWG cables would suffice, and I'd use 3 for the ground.

Sorry for getting longwinded... I'd be glad to help out any more if I can.

welder feed

your best bet would be to run a line from the panel (8/3 UF) to a receptacle by your welder...put a new 50 amp breaker in and your all set... let me know if you need more info... joe

From what I was told on the flow of electricity, it flows on the outside of the wire, not the inside, so if using smaller wire, you want as much surface area on the smaller wires as the larger single wire has. So to do this you need to multiply the diameter of the wire times Pi ( 3.1416) to get the circumference ( distance around the wire) Most Home improvement stores cary large gauge extension cords suitible for 220 use, unless you live in BFE , I don't see why you'd have trouble finding one to work.

You could probably find charts online that have the diameter for each AWG size, and resistance for a given length... I got it outta one of my older EE books, but I figure you could find it all online just as easily. Its also possible to figure out the resistance if you know the resistivity and the length, but it's just so much easier to look at a chart, LOL.

You should be able to get the maximum current draw from Lincoln... If you know that, you can calculate the transformation ratio, which you can then use to figure up the current the welder would need to give a specific output, or figure what the maximum output is for a given max current input.

What D. Hearne is talking about with current traveling on the outside layer of a wire is called the skin effect. This is true, but it is dependent on the frequency, and at 60 Hz it shouldn't be a real issue (although I hate solid wire, not only b/c of skin effect but its just a general PITA to work with when you start getting up in gauge). It's caused by the wire's self-inductance, when the changing current of AC flows through the wire, it creates a magnetic field that induces a voltage that opposes the flow of current.

Transformers also use inductance caused by the changing current, but they use an actual magnet with wire wound around it to induce a voltage in another wire thats wound around the magnet, where the number of turns is directly related to the output voltage. Thats how the voltage selector on your welder actually works, it only uses so many of the available windings to induce a lower voltage than if it used all the available windings.

AC is really neat in how easily you can manipulate it, it would suck if back in the olden days they woulda decided to use DC instead of AC in our houses. I could go on for hours, AC is just a really great thing.

With the 30A breaker, you are just limiting your input current which limits the output current that the transformer can induce on the output side... This won't hurt the transformer, just limit your max output. Like I said, if you get the max input current the welder needs to make its max output current, the transformation ratio can be figured out and then you can figure how much input you need for a specific output current and so on. Transformers are really amazing, considering how useful something so simple really is.

I like your idea of 3 ground wires and 2 hot/common wires, you can't overground. Safest way of doing that.

You make a cord from 8/3 sjo cord which is not $3.00 per foot.Using a dryer outlet is only a 30 amp circuit. One guy had it right to run from the panel and get your plug close. I have made cords for other guys so they can move the welder around in there shops.You can run 8/2 romex inside or if going outside or underground use the uf cable. let me know if you need more help.

Swade214 said:

You make a cord from 8/3 sjo cord which is not $3.00 per foot.Using a dryer outlet is only a 30 amp circuit. One guy had it right to run from the panel and get your plug close. I have made cords for other guys so they can move the welder around in there shops.You can run 8/2 romex inside or if going outside or underground use the uf cable. let me know if you need more help.

Click to expand...

I agree. I made a 50 ft extention cord out of sjo cord and dryer receptacle ends. "mcmastercarr.com" 8/3 SJO cord about $1.45/ft. $70 and you are done. It lets me weld and run my 220V wood planer anywhere in the shop or driveway. When I lived at home, I ran it through the door to my mom's dryer receptacle. In my shop I have a 220V receptacle right next to my breaker panel, which was an easy install.