220V wiring question

Ukraine Train · #1 07-29-2010, 07:45 PM

I finally got replacement parts for my welder that I bought off a guy after it fell of his cart and broke, now I need to figure out how to wire it. The welder manual says the plug is a 3 wire 50A 6-50P:

but the plug that's actually installed (by the previous owner I think) looks to be a 14-50P except there's no terminal coming out of the half round hole, just the three blades.

My outlet (laundry room off the garage) is a 4 wire 14-30R and the circuit has two 30A breakers joined together. One breaker for each hot, right?

So my question is, when I get a plug to fit into my receptacle, how do I wire the welder to the plug? Do I just not connect anything to white? Just match up red and black to the straight blade terminals and ground to the half round one? I need to learn more about home wiring...

ferociousllama · #2 07-29-2010, 08:31 PM

It sounds like you have a 30/50amp plug where you can interchange the straight lower pin (the middle one I guess you could call it) for a L shaped one and use it for a 30 amp dryer plug. I have that same plug on my miller dynasty.

The "upper" pins on the plug should be the hot ones, then the other one is the ground.

That's how my welder is wired, I'd read the maunal for your welder before putting power to anything because it could be different.

It is easy to make an adapter cord to adapt from your wall to welder.

If you're not sure what does what in the wall outlet use a voltmeter, it makes life easier than blowing up expensive tools and potentially hurting yourself.

WildStyle · #3 07-29-2010, 08:31 PM

Why not get the proper receptacle for the wall? Which would be a 6-50R.

Scrambled · #4 07-29-2010, 08:54 PM

your x and y SHOULD be the hots, the G is the ground, and the w is the neutral. The newer building codes require that a neutral be used in the newer driers.

Steve

Benderboy · #5 07-29-2010, 09:26 PM

Quote:

Originally Posted by Ukraine Train

I finally got replacement parts for my welder that I bought off a guy after it fell of his cart and broke, now I need to figure out how to wire it. The welder manual says the plug is a 3 wire 50A 6-50P:

but the plug that's actually installed (by the previous owner I think) looks to be a 14-50P except there's no terminal coming out of the half round hole, just the three blades.

My outlet (laundry room off the garage) is a 4 wire 14-30R and the circuit has two 30A breakers joined together. One breaker for each hot, right?

So my question is, when I get a plug to fit into my receptacle, how do I wire the welder to the plug? Do I just not connect anything to white? Just match up red and black to the straight blade terminals and ground to the half round one? I need to learn more about home wiring...

First things first! How many amps does your machine draw? If it draws close to the 50 amps the plug is rated for and your outlet is only 30 amps, you are going to be tripping your circuit breaker if you're running your machine close to maximum output. Always remember that the circuit breaker is there to protect the downstream wire, so make sure you don't install a larger breaker if the downstream wire is not sized accordingly.....unless you're a pyromaniac.

Benderboy

Ukraine Train · #6 07-29-2010, 09:36 PM

Quote:

Originally Posted by ferociousllama

It sounds like you have a 30/50amp plug where you can interchange the straight lower pin (the middle one I guess you could call it) for a L shaped one and use it for a 30 amp dryer plug. I have that same plug on my miller dynasty.

Yep, you're right. Unfortunately the plug didn't have the spare pins in it to hook up ground correctly. The ground wire was connected to the lower pin (neutral right?). So the previous owner never had it grounded. I bought a new connector that has all the pins and connected the ground correctly to the top round terminal and each hot wire to the side terminals. I fed a new spool of wire and it struck an arc on a piece of metal I had lying around. I don't have gas yet but I just wanted to make sure everything else worked first, and it seems that it did.

The welder draws 20A. It's a Lincoln SP170T. So it pulls 10A @ 110V for each hot wire, right? The manual says a 40A Super Lag breaker is required. This circuit has two 30A breakers tied together so I think I'm ok?

Ukraine Train · #7 07-29-2010, 09:44 PM

What do you guys recommend I use for an extension cord? Home Depot didn't have anything for 220V. Can I make my own just using some romex and plugs or is that not enough insulation for an extension cord? Do they make extension cords that have the 30A dryer plug on it?

Edit: Or since I just bought a new plug, maybe I should just buy some 3 wire 8ga cable and make a longer lead for the welder without using an extension cord and put my plug on it.

ferociousllama · #8 07-29-2010, 10:49 PM

if you need a 40 amp breaker then you need to replace your 30 amp breakers for 40 amp and make sure the wiring to the plug can sustain 40 amps.

Each one of the two breakers you describe can put out 30 amps at 110v. That means between the two breakers that's 60 amps of output at 110v. When we're talking about 220v, that's only 30 amps. So if your welder draws 40 amps of 220v current, then you need two 40 amp breakers.

You can try running it the way it is but circuit breakers are really meant to pop under "catastrophic loads" like a dead short. I have seen breakers not pop when the breaker amperage was doubled for a short time. Make sure the wiring can handle 40 amps and if it can, then weld. If you find the breaker blowing too much then switch to a higher amp breaker. If you do change the breaker make sure the wall receptacle is rated to handle the load with the new breakers.

wyoming9 · #9 07-30-2010, 04:01 AM

Most commercial equipment as of now has not upgraded to the 4 wire code which can get quite confusing

It all comes down to how your shop is wired . now most welders still use the black and white for hot and green is still the standard ground of course this is for 230 volts single phase when using 3 phase the red wire becomes the 3rd leg.

It is always a good bet to pull the covers off when dealing with anything not brand new out of the box. It is down right scary what one can find sometimes

When you need to extend the length of you input cable on any but a short usage just make a new input cable replacing the short one with the longer one making sure to get your connections tight if needed just draw a quick drawing which color wires go where .

It is the connections with extension cords that often can cause problems on welders and plasma units