Question about installing wiring for a Miller Thunderbolt 225

Have a question or want to show off your project? Post it! No Registration Necessary.  Now with pictures!

Threaded View
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.

Re: Question about installing wiring for a Miller Thunderbolt 225
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.

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

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

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

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

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



Re: Question about installing wiring for a Miller Thunderbolt 225
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


Quoted text here. Click to load it



Re: Question about installing wiring for a Miller Thunderbolt 225
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.

This link shows type fittings that should be used.
 http://www.cornerhardware.com/cat_581/Electrical/Conduit-Fittings/PVC-Conduit-Fittings.htmlOne
inch conduit should be fine for 3 #8 THHN wires. A weather proof fusiblesafety
disconnect should be install at the remote end of your conduit run."Frank
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.



Re: Question about installing wiring for a Miller Thunderbolt 225
I've read three other replies and some pretty good advice was offered.
At least check with a local electrician or the electrical inspector.
However, one thing has not been mentioned - your home owner's insurance.
  The more professional, and safer, the job looks the less likely that
your home owner's insurance will be canceled and/or converted to regular
fire insurance.  OTOH, if it appears you are starting a business in the
yard the insurance could be canceled or adjusted anyway!  You may want
to discuss this with your insurance agent - if it is to be a business -
and be sure you will be covered should something happen.  If it is a
hobby I don't think I'd worry about the insurance part, just be safe
with your welding and keep a GOOD fire extinguisher, bucket of water or
water hose close by for the unexpected.

Frank Johnson wrote:

Quoted text here. Click to load it

Site Timeline