wiring for welding

[RobJ]

I suggest not listening to some of the posts here. You HAVE to by code wire the (in this case welder) per the plug being used. MOST welders use the 220v 3 prong 50 amp plug. (hot lead hot lead and ground no neutral.) also used to be referred as a stove plug. This is a 50 amp plug and the wiring feeding that plug MUST be approved to handle 50 amps continuous! if the welder needs it or not!

depending on the wire used you more than likely will need to use 6 GA wire. 8 ga is rated usually to 45 amps ONLY...

Mark M

p.s. I guess you don't HAVE to do anything, but if there is a fire and the insurance finds that there is something wired wrong that YOU did you are finishing paying the mortgage not them . also if you were ever SELL the place and the next inspector found this plug (this is a place that most home inspectors see a 50 amp plug they will WILL look to make sure the wiring to that plug was correct. it is same if you put in 20 amp outlets you have to by code use 20 amp rated wire (12 gauge that is)
so if you want to risk burning down the place then by all means wire the plug as you see fit. I say this only because most people think that doing electrical work is some thing that any tom dick or harry can do. and that is why every home needs to have an independent inspection done by the people LOOKING at buying it not the person selling it or the Realtor as the Realtor only gets paid if the place sell...

BUBKUS!!

 

[mudcat]

First, I think it's wrong for a manufacturer to include a plug that will fit into a range outlet. One is a NEMA 6-50R the other is a 10-50R. The 6-50R is the correct one. Most welder supply houses will have it if you ask for a welder outlet. Is it more convenient to install a range plug? Yes. Because they are more readily available. And people don't know there is one dedicated for a welder.

If you look at Table 310-16 of the current NEC, there is an asterick on #10 wire. The asterick directs you to Article 240-4(D) which directs you to 240-4(G) for Special Conductor Appilcations. That in turn says to look at Article 630 for Electric Welders, which says for one welder on the circuit, you can fuse the feed for the welder at 200% of the conductor ampacity. #10 THHN/THWN is actually rated for 40 amps, so if I fuse it at 200%, it's good for 80 amps for a welder.

But we can agree to disagree.

BTW I didn't make a recommendation in this thread on the receptacle, just the previous ones.

I love it! Imagine the confusion if the discussion were on motors!
Have a Happy New Year Inspector507!

 

[Iceman65]

Hmmm, interesting reading here.

 

[patrick_g]

Hmmm, interesting reading here.

Yes indeed, verrrrrrry interesting but...

Lets see if I can put out the flames with a dash of gasoline and some breeze.

Let me assure everyone I am not a licensed electrician or an electrical inspector but have gained a little experience being around electrons for a few decades (have made living as electronic engineer for a while.) My take on this thread is pretty close to Gemini's.

While it is theoretically possible (I have done it) to use two separate 120 vac circuits to produce 240vac it is NOT recommended.

Q: What is a 240 VAC breaker?
A: Two 120 VAC breakers mechanically ganged to "KILL" both legs if either one meets the "trip" specs.

The idea stated about 120VAC running through the welder's transformer to neutral and then the other leg of 120 running through the transformer to neutral is one way to design a welder BUT it is not the way any of the welders I have ever seen are designed. Common welders like a Lincoln tombstone has 240 VAC applied across the primary which is NOT center tapped for a neutral connection.

There are two areas of concern in sizing the wire for a welder. 1. the wires from the breaker to the outlet and 2. the wire from the plug to the welder. Wire #1 is to be sized to meet code and prevent a fire in the wall or wherever and as Gemini pointed out should never be undersized compared to the breaker, NO MATTER WHAT!!!

The wire (called #2 above) from the plug to the welder, supplied by the maker (often with plug) may and often is of lesser size than the wire needed in the wall.
Q: Why is that?
A: the wire is short and exposed to cooling air and is big enough for such a short run and saves the mfg a buck.

Long wires drop more voltage at any given size (waste power/make heat) short wire may drop more volts per unit of distance but thankfully are short so do not ordinarily cause a problem in the case of the power cord of UL approved equipment. The manufacturer has covered his backside liability wise and his choice of wire size for the short power cord supplied is OK. (well, OK enough)

Do not even begin to think if it is good enough for the manufacturer it is good enough for you and run the same size in the wall. BAD IDEA!! (see above)

I didn't note for sure if the original poster was wiring in the basement and welding elsewhere or welding in the basement. If welding in the basement the ventilation is most likely woefully inadequate and as others pointed out, a respirator will help the weldor but not anyone sharing the house. IF there is a basement window AND it were fitted with a powerful exhaust fan AND the welding took place so that the fumes were immediately exhausted and not mixed into the basement air then maybe it would be acceptable.

Readers Digest version: Don't weld in the basement without proper ventilation. Use a wire size approved for what you are doing and IN NO CASE rated for less amps than the breaker, hopefully more.

Saving money by reducing the size of wiring in the wall is not safe or smart as several posters mentioned.

Is playing Russian roulette with your fire safety worth saving a few bucks? OK, honey, so the house burned down but I saved almost $20 on wiring and when I get out of inhalation therapy if the insurance doesn't find the reason for the fire we can...

Pat

 

[wedge40]

I haven't read every post,but I've said this before on TBN. There are somethings that should left to the professionals. I'd hire an electrician to install it, that way if something does happen you have certification that it was done right.
I'm not sure if you can (or should for that matter) put a welder in your basement. I dont weld but I had my brother weld something for me over the Christmas break. We were in a 30x40 garage and I was standing at the opposite end of where he was welding. After three days I still had black stuff coming out of my nose. Not sure I'd want this in my basement, and don't think the little misses would either.

Wedge

 

[keeney]

The wire rating in the wall has to deal with being completely buried in insulation, bundled with other wires, and if it catches on fire in the wall, you might not notice rright away, or even be able to easily find the smoldering area and put it out.

If the the cord on the appliance gets too hot while you are using it, you likely notice right away. Like the other day I had a cheap extension cord end go up in smoke while using a circular saw (the end must have had a bad connection). There was little danger, but a lot of smoke and smell and I simply tossed the thing out into the snowbank Same thing happen in the wall? Could have burned down the whole house.

Another issue with a basement for welding is fumes from other sources that can collect in low areas. Make sure you don't have any paint thinner or gas cans stored down there.

- Rick

 

[gemini5362]

Guys let me point out something here. Inspector 507 is quoting what the NEC says. He has years and years of experience as a licensed electrician he is currently an electrical inspector. I am very sure that what he is quoting is correct and is acceptable practice. The reasons behind it are very sound. You dont leave your welder on making an arc for hours and hours at a time. You strike the Arc melt the rod for a bit then stop and see where you have to grind down( or at least if you weld like me you do).The posters that say hire an electrician to do the work are probably the most correct posts in this thread. If you hire a licensed electrician to do the work and something happens that your house burns down due to an electrical fire the insurance company is going to pay off with minimum questions asked. The insurance comapny might have a long talk with the electrician but you are going to be covered. If my house burns down due to an electrical fire since I am not an licensed electrician I am going to have to do some serious arguing about my wiring practices. I have enough experience as a commercial electrician and I try to exceed the minimum NEC requirements when I wire something so I am not worried about that arguement in the event it happens. I went back and checked the wiring going to my welder it is 10 gauge which covers the input current on my welder. I have my welder on a 30 amp breaker. My own personal opinion is that breakers are a protective device, as a protective device I believe they should match the device they are protecting. I dont think the weakest link in the power chain should be the wire going through the wall. But that is my personal opinion. The one thing that I think everyone will probably agree on is that there is nothing keeping you from exceeding the minimum requirements of the NEC. If the minimum requirement is 10 gauge there is nothing stopping you from using 8 gauge. If the NEC says you can use a 50 amp breaker there is nothing stopping you from using an 30 amp breaker. I think Patrick g's sentiment sums it up pretty well. Gee dear I know the house burned down and we lost all the pictures of the kids and our family, I know that we lost the desk that had been in your family for 24 generations but I saved a couple of hundred dollars on the wiring for my 2000 dollar welder.

 

[Inspector507]

The one thing that I think everyone will probably agree on is that there is nothing keeping you from exceeding the minimum requirements of the NEC. If the minimum requirement is 10 gauge there is nothing stopping you from using 8 gauge. If the NEC says you can use a 50 amp breaker there is nothing stopping you from using an 30 amp breaker.

I agree completely.

The original poster was concerned with the 12/3 cord on the welder. I would say he is okay.

 

[KubotainNH]

Man, this is a hot topic, no pun intended. Let me state a few things and hopefully this thread can be put to bed. The difference between paying an electrician and doing it myself is the difference between getting to use the welder and not, at this point I cannot afford to pay someone to do it. I have done electrical work for 20+ years and the final outcome is usually better than if I paid someone, I never scrimp on this stuff just don't want overkill. BTW, my existing welder is in the basement right near the walk out door so that I can weld outside or if needed open the door wide and weld just inside out of the weather with a fane blower out. Any new wire I run will not be within the wall and will be removed if I move. Attached is a picture of the current plug on the welder. Thanks for all the posts.

 

[KubotainNH]

The picture is on this post. Now that I look at it and google the 6-50R one they look to be the same. So no range plug.