Question about installing wiring for a Miller Thunderbolt 225

I want to install a dedicated circuit for a Miller stick welder. The front of the welder says it pulls 47.5 amps, and I've been recommended to use a 60amp breaker at my main panel. I've read some posts/questions on the net similar to this, and I believe I need to use 6-3 or 8-3 Romex wire. The distance from the main breaker panel to the receptacle will be about 80-100 feet, and the welder has a 15ft cable to plug into the receptacle. All I really plan to weld is 1" and 2" square tubing and angle iron...nothing too heavy duty.

If it is safe (and does not violate NEC), I will run the wiring from the main panel into the attic and bracket it to the roof truss to run across the attic. What I would like to know also is if it is safe/legal to drop the 8-3 or 6-3 Romex through the eve of my house and run it along the ceiling of my back porch into my garage. My eves, porch ceiling, and garage wall are made of cedar. Will there be a problem dropping running the cable this way, or should I drop it down the side of the house (made of brick) and run it underground to the garage?

This job does not seem hard to do, but I want to do it right and more important, SAFE. Any suggestions or recommendations would be greatly appreciated.

Thank you.

Reply to
Frank Johnson
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Seems pretty simple doesn't it...

  1. Romex is not intended for exterior use, or where it is exposed to possible damage. It is OK for running through walls and attics. But forget running it under your eaves and porch.

  1. Romex is not intended for running through conduit. THHN, etc. are.

  2. Some jurisdictions don't allow Romex at all.

  1. Depending on temperature ratings of the wire, breakers, panel, etc. and the maximum ambient temperature you experience even 6 gauge wire may be insufficient.

  2. My guess is your local government requires you to obtain a permit for this kind of work.

  1. IMHO you need to check with a local electrician or building inspector to find out what is acceptable where you live.

Reply to
Footy

The safest route is to check this out with an electrician or discuss it with an electrical inspector. Not all areas have identical rules and not all electricians and electrical inspectors interpret the rules the same way.

I am not an electrician but have done some electrical stuff. My totally unofficial thoughts on the matter are: Romex is not outside or underground wire but it can be protected. After coming out of the eave beside the porch I would run it in a corner and box it with cedar or suitable cover. Make the distance from the outer surface of the box to the wire at least 1.5" and leave some air space around the wire. The idea is to protect the wire from physical damage and don't let the wire overheat. Overheating is not likely to be an issue because at the maximum current output of your welder when it is drawing maximum input current its duty cycle is probably around 20%. Also with stick your duty cycle is low since you are changing rods, position etc.

Welding light tube and angle are probably will mean you will be drawing about 20-25A input except when you stick the rod down and if the welder is not set for maximum output current even this won't cause it to draw maximum input current because it is a current limited constant current device.

If you can, put in the #6 since this will cover you for any future requirements and it is just the better way to do it. It is not as easy to work with because of its size. This normally will allow you to supply it with a 60A breaker. For work such as this you could certainly get by with a #8 wire which is generally rated for use with a 40A breaker. I have a Miller stick welder on a 80' run of #8 supplied by a 40A breaker. My materials are typically the size of yours and I have never popped the breaker even with the rod stuck down till it glowed. I have also run beads for fun at over

200A with no problem but only for short periods of time.

Again, I emphasize if you want to be safe, nobody can argue with that, get some professional advice. Billh

Reply to
billh

The best way would be to run pvc non metallic electrical conduit from your service panel to the end point. Use weather proof LP fitting at your 90 bends to make wire pulling easier. Make sure your conduit is at least 24" under ground or more if your code requires. You'll need to secure the conduit with plastic straps.

15ft> cable to plug into the receptacle. All I really plan to weld is 1"> and 2" square tubing and angle iron...nothing too heavy duty.>> If it is safe (and does not violate NEC), I will run the wiring from> the main panel into the attic and bracket it to the roof truss to run> across the attic. What I would like to know also is if it is> safe/legal to drop the 8-3 or 6-3 Romex through the eve of my house> and run it along the ceiling of my back porch into my garage. My>

eves, porch ceiling, and garage wall are made of cedar. Will there be> a problem dropping running the cable this way, or should I drop it> down the side of the house (made of brick) and run it underground to> the garage?>> This job does not seem hard to do, but I want to do it right and more> important, SAFE. Any suggestions or recommendations would be greatly> appreciated.>> Thank you.

Reply to
Lance

Reply to
Al Patrick

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