I can't play with my new toy without your help

[The Red Baron]

I recently found a deal on a Miller 210 with 100 CF tank, SpeedGlass mask and 15 amp 14" Milwaukee cut off saw for less then my plan "A" 110V welder was going to cost just for the box. Needless to say I am about to install a new to me Miller 210 MIG welder in my garage. :cool2:

In my past two homes I have run extra 110V circuits for extra garage outlets but this 208/230V has me cautiously skeptical that I am up to the task. Is either the same or close enough to 220V? I tried to seek help at the local Mega hardware stores (Lowes and Home Depot) with no luck. They both carried 230V welders and yet neither had a clue about or could supply the required NEMA 6-50 hardware to use them, utterly frustrating! :cry:

I have a 200 Amp service box in the garage wall. The welder needs 230 Volts and draws 27 Amps maximum. It is a single phase machine. The welder came with a 10 foot long power cord with attached NEMA 6-50P plug. The cord casing is embossed 12/3. I want to install a NEMA 6-50R surface mounted receptacle through the back of my electrical panel and use a 25 foot long extension cord to allow me to roll the welder around my project vehicles. I would like to purchase a 25', 10 gage 3 stranded 110V/15A extension cord and swap the ends to NEMA 6-50. It may sound bad but it is 10 gage... OK, I really don’t know what the hell I’m doing at this voltage level, any help or links would be greatly appreciated! :blush:

[gregben]

You can run the welder just fine off the power in your electric panel.
In the U.S. residential electrical service is nominally 120/240 VAC. The
electrical service coming into the house is supplied from three wires,
two black ones and a single white one. A ground conductor (green) is
also required and is attached to the inside of the electric panel. The
two black wires are "hot" and the white is "neutral". The voltage across
hot #1 and neutral is 120V, and the same for hot #2 and neutral. The
voltage across the two hot leads is 240V. The welder specifies operation
at 230V because the measured voltage across the two hot wires under
load will be less than the theoretical 240V.

As far as extension cords and supply leads go, I recommend buying a
single length of 3 conductor cord of just-sufficient length to meet your
needs, and wire it directly into the welder at one end and to a plug
at the other that plugs into a receptacle near your electrical panel.
This means no extension cords and not using the 10' cord supplied
with the machine.

The 3 conductors in the cord are the two hot leads and the protective
ground, and all must be the same size (wire gauge), preferably #8 if
you are running about 40' overall.

The electrical panel will probably need to have a 30A fast-acting breaker
designed for 240V operation, but follow the recommendations of the
Millermatic 210 instruction manual to be certain.

[The Red Baron]

OK, at 40 feet of total distance would make for 1/3 of the recommended 118 conductor length. Is it still recommended to us #8 wire in a single length?

For fuse or circuit breakers it mentions "Time Delay" and "Normal" but no mention of Fast breakers.


Thanks for your help, it's killing me to have wanted this for so long and not be able to hook the dang thing up! :p



This is what I am working from...

[wannabe_welder]

10 gauge is fine for a 40 foot extension cord.

Try this.
http://www.csgnetwork.com/wiresizecalc.html

[Sandy]

Just a note that the 27/28 amps mentioned is 27/28 amps at its rated output which is at 160 amps on the DC side. Should you need to run hotter than 160 amps then that input requirement will climb somewhat. That is why they rec a 30 amp 'slow blow' equivalent or 40 amp conventional breaker.

Other than that I'll ditto what wannabe said.

Bad news when the big box stores don't have what you need in the 6-50 electrical supplies. Did you fill them in on what it is they need to get on the shelves???? :)

[gregben]

I took a look at the datasheet (not the installation manual) for the MM210
and it specifies 27A @ 230V input when operating at "rated output" of 160A
(60% duty cycle). Since the machine will output up to 210A for short periods (30% duty cycle) the input current will no doubt exceed 27A, so as Sandy
said, a 40A "normal" (fast acting) breaker or 30A "slow blow" (time delay)
breaker is called for.

[awright]

I'm surprised that you can't find the 6-50 receptacle at your big box store. I believe that I've purchased 6-50 receptacles at my local Home Depot several times.

However, you can definitely get the 6-50 connectors at your local electrical supply or welding supply house. I've never been refused service at electrical suppliers even though they are nominally for contractors. They have no reluctance to sell to individuals (although you may pay a premium price for not being a contractor).

awright