220 volt wiring question

[dlgeis]

I just bought a Lincoln Square Wave Tig 175 Pro welder.

The wiring/fuse recomendations are 10 ga/100 amp.

I have a 200 amp home service and a 200 amp panel with two empty breaker slots and two unused 220 v circuits. The unused circuits each have double 30 amp breakers. My home electrical needs are modest so I don't see a max capacity problem.

1. Does a 220v circuit with a double 50 amp breaker = 100 amp circuit or do I need to find a double 100 amp breaker?

1. Do I have to give a modern welder its own box wired directly to a meter lug to prevent problems with sensitive electrical equipment in my home or can I get by with just adding it to my existing box.

2. If I need to separate it can I do so by connecting the feed wires to the same lugs used on the incoming side of my home panel. ie two wires connected to each lug above the main breaker and then feed to another small 100 amp panel with its own switch and breaker? Or are the lugs designed to secure only one wire.

Thanks

Doug

[Scott Townsend]

I'm not an electrician, but have wired a home or few.

Kind of odd that it would want 10ga for 100amps. 10ga is only rated for

30amps. If your tig was going to pull 100 amps, I'm pretty sure that the 10ga wire would not support it.

I dont have my County Code book with me, but it went something like this: An Electric Oven/Range needs a 6ga wire at 70amps for its needs I think just the Electric Oven can get by on a #10 at 30amps, Same with an AC HiSpeed Electric Dryer needs a #8 @ 50 Amps.

For your Questions:

1) When you say A Dual , I think you just mean a 220v Breaker. Where the 2 breakers are switched with the one lever, So you would need a 'dual' 100. The 'Dual' Allows the breaker to hit L1 and L2 of the Bus Bars. (Both Hots, that's where the 220 comes from) This is different from the Dual Lever, single form factor breaker. This will allow two 120v connections in a single breaker slot (your panel has to be keyed to accept it) So you could get a Quad Dual, where the Inside and outside are switched together across L1 & L2, so you could get two 220v circuits in 2 breaker spaces.

2) You should be able to add it to the Existing panel on its own Circuit. Addend a Separate panel would be unnecessary.

3) Lugs are typically used for the one. Is your house panel fed from a Main panel elsewhere? Does the main Panel have more room for additional circuits? My House has a Main Meter Panel with 42 Circuit capacity & the Meter Main. I use it for all the 220v and for feeding the house Sub Panel and the Garage Sub Panel. So it has two 100amp breakers feeding the Sub Panels, 50amp for the Oven, 30amp for the Dryer and 30amp for the AC.

Hope that helps

Scott

[gfretwell]

I am jealous

I looked at the Lincoln site

... and that is certainly what it says if you have the 53 or 59 amp input on the label.

double 100a and they should have it at Home Depot.

add it into your panel in the available slots, you shouldn't have a problem. "Electronics" are not that sensitive to line noise. You may get some from the arcing through the air but that is not on the input side.

Welders are a different breed of cat so a lot of what people "know" about wiring does not apply here. You base the wiring on the duty cycle (25% in your case) and you can size the breaker to 200% of the input amps. So if we start with 59 amps from the label, you can use up to a 118 amp breaker, Lincoln says use 100. Take their recomendation. The wire size is determined by duty cycle using table 630.11(A) if you don't have the info on your label. You fall between 20 and 30a so the multiplier is between 0.45 and 0.55, call it 50%. Half of your input amps (59) is a tad less than 30 and that puts you in 10 guage wire. Clear as mud huh? That is why Lincoln gives you the label.

Have fun

[zxcvbob]

Cool. I want one. :-)

If you can't find a double 100A breaker, put a 60A or 70A in as a temporary while you continue to look for a 100A.

Depending on how far the wire run is, I might use 6 gauge Aluminum SE cable. That's probably cheaper than #10 copper right now, and it wouldn't get as hot when operating at maximum current and maximum duty. (assumes proper termination of the AL ends)

I think I used #8 copper to hook up my little welder, on a 50A circuit, but copper was cheap back then.

Bob

[Steve Barker LT]

I assure you those welder ratings are always way off. A 30A double with

10ga wiring will be just fine. We ran our whole garage, (including a 250A Hobart MIG) with a 10ga underground feeder. Never any light dimming or voltage drop. I don't see where you got the 10ga/100A thing.

[gfretwell]

He got the 10 ga 100a thing from the manufacturer but I will agree that he can certainly try the 10ga on the 30a if that is what he has. It may be a nuisance trip problem.

[Chris Lewis]

According to Steve Barker LT :

He's probably confusing the output current of the welder with the input current. Welders contain transformers that convert high voltage low current to lower voltage and higher current.

Assuming 10ga was the recommended circuit wire size, the input amps are around 25-30A.

A 100A circuit is going to need 4ga copper or 2-3 ga Al. That's some huge welder.

[gfretwell]

You really need to read NEC 630 before you say this. With a welder you can have an overcurrent device set to 200% of the input current and you can size the conductor to as little as 45% of the input ampacity. In his case that number is 53 or 59a so the conductor could 10ga with a 100a breaker.

[zxcvbob]

It is a big welder, but welders have special allowances in the NEC that take into account the duty cycle. They also are not very succeptable to voltage drop in the supply lines. Read section 630 (I think that's the right section) and be very surprised.

Best regards, Bob

[Pop]

I'm glad you came along with the right answer. It's disgusting how many people will offer advice when they're really guessing and have no idea what a particular piece of equipment requires. If only people would RTFM and only answer when they really know what theyr'e talking about. Guessing is so useless.

Pop`

[Chris Lewis]

According to :

Yeah, I guess so. Last I looked, CEC didn't have anything on it like this.

[gfretwell]

I think I would try a smaller breaker if had it. I have been running my "buzz box" on a 30a breaker for 3 decades and it calls for a 50. If you are going to have to buy a breaker you might as well get the one they call for. I agree NEC 680 is one of the stranger articles, particularly for people who have 240.4(D) burned in their mind. That is where our familiar amps per wire size rules come from. It is the "belt and suspenders" safety factor rule. You can't go wrong with

14=15a, 12=20a and 10=30a but it is probably more than you need for dedicated motor, welder or HVAC loads

[Chris Lewis]

According to :

I think it's _very_ common that (non-pro) people with welders that call for 50A breakers are running them off 30A dryer receptacles.

A friend (professionally trained welder who now only does hobby stuff) said that at the highest setting he'd ever use, he gets about 18" of bead before the 30A breaker trips. So, he simply does 12" and lets it cool off a bit before continuing. More relaxing that way anyway he says.

My "efforts" (hah!) at stick welding stop at about 4" ;-)

I perhaps wouldn't have been quite so confused if he hadn't said 100A - it sounded more like the output current of a small welder. Rather than the input current of a welder rather larger than a hobbyist would be likely to try using. Whereas it was more or less an ordinary 50A one.

I'm quite familiar with the CEC rules for motors which are similar (but not quite as drastic), and by extension am aware of the NEC ones (eg: work with the electrical FAQ). I don't think my copy of the CEC has anything for welders. But my copy is, after all, about 15 years old.

[gfretwell]

I agree. It had me scratching my head and I looked up the PDF on the Lincoln site. Sure enough that is what it says, along with "per the NEC" so I looked up the welder rules in 630. Until I ran the numbers I had a hard time getting my head around it too but that is what it says..

[yourname]

I have been running this welder on a 50 amp breaker for at least 3 years. Never thrown a breaker. Welding aluminum I have duty cycled out[welder quits, light comes on]

I personally would run it on the 50 amp with wire to match, unless you need a long run of wire;nix that, a long run would give your voltage drop.

Wait, I'm lying, I just looked, it is a run of 10-3 sjo....extension cord from the welding supply is 8 ga. Obviously it works...

BTW home centers usually quit at 60 amp breakers, and they start getting pricey, unless it has changed. haven't look for a bit

[e-mail] wrote:

[zxcvbob]

My opinion: It doesn't actually /need/ a 100A breaker; a 60A or 70A will work just fine. But if you stick the electrode while doing shielded metal arc welding (stick welding) at the machine's maximum current setting you can pop the breaker. So the electric code lets you oversize it. Lincoln and Hobart and Miller don't care how much the breaker costs, they just recommend the size that give the least trouble regardless of what you try to weld. If your technique is good and you only operate the welder at half-power or less, you can probably get by just fine with a 30A breaker. You'll still need 10 gauge wire because the maximum duty cycle is probably close to 100% by the time you get down to 30A input current.

Best regards, Bob