Help getting welder wired in!

[gemini5362]

I was never worried about damage to the breaker. My concern is exactly what is being discussed now. If you have a mouse chew through a wire and short accross it then you have the potential for more current through the wire than it is designed to handle before the breaker trips. UL may have listed welders as a situation where you can have a wire with a lower amp rating than the breaker that feeds it is designed to handle. I am amazed that the NEC would allow that and for my own personal preference it is not something I would ever allow in anything that I worked on.

 

[SnowRidge]

I was never worried about damage to the breaker. My concern is exactly what is being discussed now. If you have a mouse chew through a wire and short accross it then you have the potential for more current through the wire than it is designed to handle before the breaker trips. UL may have listed welders as a situation where you can have a wire with a lower amp rating than the breaker that feeds it is designed to handle. I am amazed that the NEC would allow that and for my own personal preference it is not something I would ever allow in anything that I worked on.

Mice are not rated even close to 25 amps, let alone 50. If a mouse chews on your welder circuit, he (and not be sexist) or she will briefly be a carbon arc lamp, but your wiring will not melt or catch fire, and the size of the breaker will have made no difference.

No garantees about the smell, though.

The real danger, as someone already pointed out, is the possibilty that the circuit later gets used for something other than a welder, such as an air compressor, or worse yet, a 220 volt heater.

I would wire it with something a little heftier than 12 gauge.

 

[mopacman]

Wow thats over 3200 horsepower. I would think the mouse would blow before the breaker......Larry

 

[Defective]

I would think the mouse would blow before the breaker.

Yup...

BOOM!!!

Little mouse bits spread far & wide.

(smoking all the way...)





Sorry, couldn't stop myself...

 

[mopacman]

I have a 220 volt plug on my on my 225 amp welder and plug my 5 HP 2 stage compreser into it and have never kicked a breaker. I think I used 5 GA wire on it with no problem....Larry

 

[gemini5362]

actually mice chewing on a wire and catching on fire is not that uncommon an occurance. There have been more than one house burned down because of that. I was using the mouse as an example. Let me see if I can think of a better example. What if the welder main transformer had a wire that had not been adequately insulated after the welder had gotten used a few times the spot shorted out. This would not make a dead short however a shorted turn transformer has some pretty high current in it. If the current did not exceed 50 plus amps ( a circuit breaker has to have a lot more current than the rated value for instantaneous trip) You could be in a situation that allows considerably more than the value of the wire. This is a dangerous situation to be in. There could be more examples but this one should illustrate the point. I agree with other posters that there seems to be a lot of people that make fun of being safe. If your welder says that is safe to do and you want to do it that way it is your buisness. I personally do not feel that it is safe to do. I also feel that the posters that point out if you use something that is more than 25 amp draw and plug it into your welder receptacle you are overloading that circuit.

 

[fishpick]

Thanks all - since the welder outlet will be all of 10' from the panel - and it will be dedicated to the welder (as I have wired the rest of the barn for other things) - I'm gonna use some of the remaing AWG 10 I have.

 

[sandman2234]

Well, if your bound and determined to do it, just use a 30amp breaker on it. What your discribing is how my tombstone 225 ac welder is wired, with a 30 amp breaker. It does fine unless I start exceeding the rated duty cycle with 5/32 rod and at 150 amp setting or more. Just use 1/8" rods, and keep it below 135 and you won't ever know it, and when your dead and gone, somebody won't make a mistake about what you have done and burn the barn down by using the 50amp breaker with wiring not made to handle it.
Think how bad they will talk about you and your wiring it that happens, not that it will matter to you.
David from jax

 

[Highbeam]

"when your dead and gone, somebody won't make a mistake about what you have done and burn the barn down by using the 50amp breaker with wiring not made to handle it.
Think how bad they will talk about you and your wiring it that happens, not that it will matter to you."

This is the biggest part of the deabte. It is huge and goes beyond the rules. If I bought a house with a 50 amp circuit and a 50 amp plug I would not hesitate to plug a 50 amp load into it which could be a disaster.

 

[SnowRidge]

This is the biggest part of the deabte. It is huge and goes beyond the rules. If I bought a house with a 50 amp circuit and a 50 amp plug I would not hesitate to plug a 50 amp load into it which could be a disaster.

My shop building already had a welder receptacle when we bought the place. I think I'll double check on the wiring.

 

[mopacman]

I dont think 30 amp will work. If you stick the rod it will kick the breaker....Larry

 

[laurencen]

just a comment, I increase the size of wire allways, try loading any circuit even a electric kettle, it gets quite warm, heat costs money and some cases fire, if you have lots of 10ga wire, run it double or triple, at the very least, this way it will be safe, the welder will generate heat, lots at full duty cycle

 

[sandman2234]

As I stated, my welder is set up on a 30 amp breaker. It runs everything below 150 amps with no problem. Ocasionally if I get busy and completely ignore the duty cycle, I might kick the breaker, but trust me, if it happened very often, I WOULD put a new breaker in, as I have a good friend who works for a Square D distibutor, and he would drop me off one with no problem. As far as sticking the rod and it popping the breaker, I would imagine the rod would be heated up beyond use if I left it stuck long enough to pop the breaker with my 1/8" 6011 rods.
For welding aluminum and anything over 150 amps, I usually just grab the Miller sitting right next to it, which is on a 100 amp breaker. It is rated at 105 amps max draw, but I have never managed to find anything that even gets close to needing it, including carbon arc, TIG welding 5/8" aluminum plate, or welding with 3/16" rod on 1.5" Stainless.
I just don't like to see fires in the walls of buildings or barns on fire. I for one would forgo the 50 amp on 10guage wire.
David from jax

 

[gemini5362]

Thanks all - since the welder outlet will be all of 10' from the panel - and it will be dedicated to the welder (as I have wired the rest of the barn for other things) - I'm gonna use some of the remaing AWG 10 I have.

I checked at Lowes last night 10 feet of #6/2 with ground is $2.25 per foot so you are talking about 25.00 to get enough to wire it and not have to worry

 

[fishpick]

I checked at Lowes last night 10 feet of #6/2 with ground is $2.25 per foot so you are talking about 25.00 to get enough to wire it and not have to worry

Fine #6 it is... Friggin strangers on the Internet caring about me and my barn...

50A breaker - #6 wire for 12' run - 50A plug... consider it done!

 

[sandman2234]

Fishpick,
Your allright, I don't care what everybody said about you!!!
David from jax

 

[gizmo]

Fishpick,

EE here. I wired my Miller 225 just as you intend to with 6AWG and a 50A receptacle. Its safe and can be used for other loads. The difference in price for smaller wire wasn't worth it to me.

FWIW, breakers have two trip mechanisms to guard against short circuit (magnetic trip) and overload (thermal trip). The short circuit let through rating really is in thousands of amps range.

I am currently working on an electrical coordination study for a major airport where let through currents are in the 200,000 amp range on a breaker that trips at 100A.

 

[gemini5362]

fishpick we would rather help you spend your money on wire than worst case scenario have you write about your barn burning down. As others have pointed out, if you get something that needs more current you can just put a plug that fits that receptacle and you have a built in receptacle for up to 50 amps and all it has cost you in wire is the price of taking a couple of grandkids or whatever to mcdonalds

 

[gemini5362]

Gizmo I have a question. I had someone give a demonstration once on circuit breakers and I am not sure I remember the numbers correctly. How much current does it take to get a standard residential circuit breaker to trip virtually instantly. I know that a fast blow fuse can blow in 1 cycle and a residential breaker wont do that. How much current does it take to get one to trip in as close as possible to one cycle ?

 

[gizmo]

gemini5362

There is a type of fuse called a "current Limiting" fuse that will clear the circuit in under one-half cycle and effectively limit the peak current to a lower value. In the residential circuit breaker world I don't believe there is a device with similar characteristics. Current limiting circuit breakers exist for industrial applications and their current limiting characteristics start to kick in at around 30,000 amps.


To answer your question though I am not sure what the minimum instantaneous trip time or current value is for a residential circuit breaker. If I were to guess it would be greater than 250 amps before clearing times dropped to near 1 cycle.