Wiring requirements for MIG welder - PeachParts Mercedes-Benz Forum

cmac2012 · #1 11-12-2007, 02:20 AM

I just bought a Lincoln 175 HD MIG welder. My neighbor at my warehouse is a metal fabricator and he confirmed my suspicion that 220 was about the only way to go. My shop has 3 phase power coming into the box, which I don't really need, no circuits wired up at any rate, and only one 220 circuit, for the baseboard heater and it's a 20 amper. I need to put in a dedicated circuit going to the garage part of my shop, 50 feet away.

Lincoln says a 40 amp breaker is required. This would mean 8-2 with ground. I've seen a couple of web sites that claim 10-2 w/G and a 30 amp breaker is more than enough. My neighbor also thought 30 would do it.

Whattyathink?

Carleton Hughes · #2 11-12-2007, 04:17 AM

Quote:

Originally Posted by cmac2012

I just bought a Lincoln 175 HD MIG welder. My neighbor at my warehouse is a metal fabricator and he confirmed my suspicion that 220 was about the only way to go. My shop has 3 phase power coming into the box, which I don't really need, no circuits wired up at any rate, and only one 220 circuit, for the baseboard heater and it's a 20 amper. I need to put in a dedicated circuit going to the garage part of my shop, 50 feet away.

Lincoln says a 40 amp breaker is required. This would mean 8-2 with ground. I've seen a couple of web sites that claim 10-2 w/G and a 30 amp breaker is more than enough. My neighbor also thought 30 would do it.

Whattyathink?

2 110 legs and a neutral Bus,8-3 with ground w/1 30 Murray breaker on each {2} hot legs.Better safe than sorry.

TimFreeh · #3 11-12-2007, 08:14 AM

I have a Lincoln 175 TIG setup in my garage that is powered via a 30 amp circuit. According to the owners manual it requires a 70 amp 220 connection to deliver the full 175 amp rating. My setup works fine up until about the 100-110 amp level - then it will blow a circuit breaker. Since I use the machine mainly for fine work (sheet metal) I really don't care about about utilizing the higher end of the amp spectrum - I typically do most of my welding at the 20-40 amp level.

At the 100 amp level I can weld steel up to about a 1/4 inch plate and aluminum up to about 1/8 inch - If you are going to be dealing with materials thicker than this you are most likely going to need a higher amp service rating.

SwampYankee · #4 11-12-2007, 08:59 AM

Quote:

Originally Posted by cmac2012

I just bought a Lincoln 175 HD MIG welder. My neighbor at my warehouse is a metal fabricator and he confirmed my suspicion that 220 was about the only way to go. My shop has 3 phase power coming into the box, which I don't really need, no circuits wired up at any rate, and only one 220 circuit, for the baseboard heater and it's a 20 amper. I need to put in a dedicated circuit going to the garage part of my shop, 50 feet away.

Lincoln says a 40 amp breaker is required. This would mean 8-2 with ground. I've seen a couple of web sites that claim 10-2 w/G and a 30 amp breaker is more than enough. My neighbor also thought 30 would do it.

Whattyathink?

If you have to put in an additional circuit and wire it up any way, why not go 8-2 w/a 40 amp breaker? It never hurts to have more capacity. You'll never regret having "too much" but you might wish you had more if you go with just enough to get by.

79-240d-project · #5 11-12-2007, 12:04 PM

Run the largest capacity your main circuit panel will allow! It can be very useful for other things as well.

You can power your house with the garage 220 via a generator set-up.

DO NOT ATTEMPT THIS UNLESS YOU KNOW WHAT YOU ARE DOING!

When I did my garage I went with the largest my house panel would permit.

E150GT · #6 11-12-2007, 12:12 PM

my electrician buddy says NMB-10/2wg is only good for 25amps. PLus current drain from distances should be taken into consideration too.

cmac2012 · #7 11-12-2007, 03:58 PM

Quote:

Originally Posted by TimFreeh

I have a Lincoln 175 TIG setup in my garage that is powered via a 30 amp circuit. According to the owners manual it requires a 70 amp 220 connection to deliver the full 175 amp rating. My setup works fine up until about the 100-110 amp level - then it will blow a circuit breaker. Since I use the machine mainly for fine work (sheet metal) I really don't care about about utilizing the higher end of the amp spectrum - I typically do most of my welding at the 20-40 amp level.

At the 100 amp level I can weld steel up to about a 1/4 inch plate and aluminum up to about 1/8 inch - If you are going to be dealing with materials thicker than this you are most likely going to need a higher amp service rating.

That's good info, I was starting to think that maybe going with the minimum would limit me on occasion. I think I'll go with the 8-2 and a 40 amper.

cmac2012 · #8 11-12-2007, 04:01 PM

Quote:

Originally Posted by Carleton Hughes

2 110 legs and a neutral Bus,8-3 with ground w/1 30 Murray breaker on each {2} hot legs.Better safe than sorry.

This welder doesn't need a neutral wire, and the box that fits their 220 cord jack, a Nema 6-50, only has terminals for the 2 110 wires and a ground.

On the 2 30 amp breakers, are you sure it's a good idea to have breakers that are rated higher then the wire?

cmac2012 · #9 11-12-2007, 04:06 PM

Good advice all around. I found an electric supply place that is getting me 50 ft. of 8-2 w/g for $1.26 a ft. which is a nickel less than Home Despot wanted for 10-2 (?!). I've run into this before -- HD seduces one into thinking that their prices are always lower and they're not.

I'm about 60 to 70% of an electrician -- I'm confident I can do this safely. I turn off the main breaker at the panel, of course, doubly important due to the 3 phase power in that box. The 3rd leg has a black cable feeding it with an orange band around it, the digital tester says it's 201 volts. Ouchy.

John1 · #10 11-12-2007, 04:09 PM

Go over to "weldtalk.com" and you will get good and info u can count on there. A lot of certfied electricians there.

John

cmac2012 · #11 11-12-2007, 04:11 PM

Hey, good tip.

Bill Ladd · #12 11-12-2007, 04:21 PM

Quote:

Originally Posted by cmac2012

The 3rd leg has a black cable feeding it with an orange band around it, the digital tester says it's 201 volts. Ouchy.

That's what we electricians refer to as a "high leg." Gives you 208 or 240 (depending on your feeder transformer's output) to neutral. If you meter between it and a 120v leg, you'll still only get the 208 between legs and can utilize such attachment for 240volt equipment. WARNING -- If said equipment has a neutral, it probably has componentry which utilizes 120v, making attachment to the high leg a very risky proposal.

As a licensed master electrician and electrical contractor, I'd recommend that you adhere strictly to the nameplate rating of the equipment and the NEC when implementing your installation.

If you have any specific questions, ask here or PM me.

cmac2012 · #13 11-13-2007, 01:26 AM

Hey, that's quite an offer. I'm mostly a carpenter, and speaking of which, do you know the difference between a carpenter and an electrician?

The carpenter wasn't smart enough to be an electrician.

That's not entirely true of course but if I had it to do over again, I'd have put in a decent apprenticeship as a plumber or electrician back when I was young enough to do it. I can do both to some degree but there are gaps in my knowledge.

One thing I do know is that I stay away from that 3rd leg. I have nothing that utilizes that type of power. I understand it can run a seriously powerful motor and save you money on your electric bill while doing it. Maybe I'll find a need to use it someday and if I do, I believe I'll get a real electrician to do run the circuit.

cmac2012 · #14 11-13-2007, 06:11 PM

Quote:

Originally Posted by Lux

That's what we electricians refer to as a "high leg." Gives you 208 or 240 (depending on your feeder transformer's output) to neutral. If you meter between it and a 120v leg, you'll still only get the 208 between legs and can utilize such attachment for 240volt equipment. WARNING -- If said equipment has a neutral, it probably has componentry which utilizes 120v, making attachment to the high leg a very risky proposal.

As a licensed master electrician and electrical contractor, I'd recommend that you adhere strictly to the nameplate rating of the equipment and the NEC when implementing your installation.

If you have any specific questions, ask here or PM me.

What was I thinking -- you're right, it's 208. I checked it again at it flicked back and forth between 208 and 209. I knew it wasn't 220 and I had an odd number on my brain.

Bill Ladd · #15 11-13-2007, 06:38 PM

Quote:

Originally Posted by cmac2012

What was I thinking -- you're right, it's 208. I checked it again at it flicked back and forth between 208 and 209. I knew it wasn't 220 and I had an odd number on my brain.

Actually, I didn't find that number so odd. Voltage will drop the further you are from the feeding transformer (as the wire length increases, so does the resistance). That's why many appliances and machines will operate within a range of voltage -- if I remember correctly, somewhere around 20% below or above the nameplate rating.