Thanks to Iggy for the table, it is good information to have.
IMHO, electrical power input and welding cables are seldom too big and are
usually just a little bit short. The reason is usually cost.
IMHE, effort spent scrounging a chunk of (too) heavy gauge industrial
surplus TECK flexible covered armoured conduit will be money and time well
spent compared with the price you will pay for a shorter piece of smaller
gauge new rubber flex extension cord.
Similarly it is hard to go wrong with 100' lengths of 00 welding cable with
Tweco ends, combined with a short set 00 ground cable and a 15' electrode
stinger whip of lighter cable which is much lighter and more flexible.
Ground cables seldom need to be as long as the electrode lead.
Scrap metal and copper dealers often get surprisingly good welding cables
(usually 00) as well as TECK and other neat copper stuff. Pick up a piece
of heavy copper electrical bus to use for a welding heat sink if available.
If you find some cables that are damaged but repairable by shortening then
the short cut-offs can be used for a great set of battery jumper cables, or
if the rubber is damaged may be quite usable for ground cable use.
I suppose you could ask Miller. I was curious about how much lead from the
welder to the arc one could use as I have a lot of welding lead and they
said on those not to use more than 25 feet on those small ones. I would
expect if you ran a wire good for 50 amps from the breaker box 200 feet
might be reasonable. It is not unusual around here to run up to 300 feet
from the transformer on the pole to the meter then figure up say another 100
feet of wire in the building not counting extention chords. That welder
probably only needs a 30 amp breaker but if you used wire good for 30 amps
it wouldn't be able to go as far. probably only using 15 amps to burn those
rods. For a more powerful welder I would think the distance from the
transformer to the panel and the gauge of the wires to the service ought to
be factored in as well. I had an electrician over one day and he said I had
a big transformer on the pole good for 400 amps even though I only have a
100 amp service and no one else is tapped in to it... yet...
The other thing you could do is check the voltage drop. measure the voltage
at the panel and then have an assistant measure the voltage at the input to
the welder when you are welding with 200 feet of cable. Miller may have a
spec but I would think 10% drop would be as far as I would want to go.
Free advice take it for it's cost.
Thanks for the advice.
200 ft. is the length I need to go from the panel to this inverter.
With the info from the other reply from Ig, I should be able to figure
the gauge wire I need to run, hopefully a standard 30 amp cord will do,
or will have to make one up myself. Think 25 ft. leads would do me if I
could make up a beefy cord
that would allow me to weld 200-300 ft. from the panel location.
Your answer is in the manual:
For 220 volt a 6 AWG cord can go up to 321 ft.
That's fairly serious cord and the manual says it's sized for 3% drop but
the machine is designed to deal with up to a 10% drop so it's likely
something smaller would work. It will depend on how much drop there at the
point you plug your extension into. I've got a 25' 8 AWG extension cord for
my MIG welder and that's $100 worth of cord and nearly as heavy as the
welder itself. 300 ft of 6 AWG cord is going to be a serious amount of
cord and a serious cost.
It's also a function of how much power you need to draw. The less power
you draw the less voltage drop there is and the smaller cord you can get
away with. If you can weld at 115 amps that's something like a 23% less
than the machines max which should buy you 23% more length for the cord you
The manual says the power must be within 10% of the required voltage or
else you might not get any output power. This implies to me it will
actually shut down if the power drops below 207 so the closer you come to
that number, to more likely you are to have problems with your welder.
If you assume the outlet you plug into is down to 220 volts, then the max
drop you could deal with would be 220-207 or 13 volts. If you run 20 amps
(a little less than the max for the machine), then the max resistance you
can have in the cable is 13/20 or .65 ohms. For 300 ft, you need 600 ft of
cable (there and back) so you need .65/.600 or 1.08 ohms/Kft or less. From
Iggy's chart, that's 10 AWG. So if my calculations and assumptions are
correct, you should be able to make it work on 10 AWG cord, but that would
give you very little room for error. If you used a little too much
current, or the voltage was a little low were you plugged your cord in, or
the welder cut off at a slightly higher voltage, you would find yourself
constantly running into problems.
So my guess is that for the full 300 ft, you need at least an 8 AWG cord to
avoid regular problems when welding near the high end of the current range
of the machine. But who knows, sometimes these things work when you
wouldn't expect them to. :)
I don't know how much of a scavenger you are but I have scavenged some
pretty nice aluminum wire, the kind which might be used for a temporary
electrical service with a wire thickness about 5/16 th of an inch. You
might even be able to put in an order at a scrap yard to get a call when
someone comes in and scraps some. Often it is three wires one bare and two
I think I would get a generator and drive it locally.
That is a very long drop and I*R =E or the current flowing times the resistance
of the wire equals the voltage drop or droop at the end of the line.
A volt meter will read full voltage. No load. Read it with some load...
Power from a pole is using very large wire.
Simply measure with the welder off then in idle and then when welding -
all at the site of the welder at the welder plug. Typically 10% loss
can be handled - but with more and more electronics going on in these
boxes are more sensitive. The old tomb stone welders - and those with
only transformers - simply turn up the output to get what was expected...
One pays for magic. One way or another!
Think of car and truck computers that stop working and a small time or
added tiny boost starts the car. Floats up the battery and the computer
turns on. Under a level and all is dead. This is why the small battery
units sold really work. Small float assists.
The product literature is here
On 220 volts the maximum current draw in any of the modes is 21 amps.
Normal voltage drop tolerances is 5% or ~10 volts. Any combination of
length and gage that gives you 1/2 ohm for the two conductors (down and
back) should be fine. Inverter welders are quite tolerant of voltage
sags, you could go even smaller than this calc would suggest.
Hint: you can take the feet per ohm in Iggy's table, divide by 4 to get
the max extension cord.
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