Extension cord for 220V?

[djradz]

Hope no one misinterpreted what I did. I didn't size the cable length based solely on the 175 amps at 30 volts, but since the welder is basically a transformer or power converter, for the most part power in equals power out, (except for a little loss in internal heat). Anyway, since the 175 amps and 30 volts was all that's known, I converted this to watts and then to approximately 22 amps input at the 240 volts. If the nameplate says 30 amps at 175 volts, we'll have to recalculate. Just a note on the tables. It looks like the tables assumed copper wire. If aluminum is used instead, you'd be way off from the tables.

 

[Gary_in_Indiana]

I think I'll make up a couple cords of maybe 25'-35' and 65'-75' in length so I'll have the versatility to go a good distance without having to have a reel trailer just for my cord. I can't imagine needing both of them together and that combination would likely exceed even the 5% drop length anyhow, depending on which outlet I used (my exisitng wiring to the furthest outlet is probably over the 3% limit already). I'd think most of the time the shorter cord would work but as soon as I only have that length my first outdoor project will need 2' more extension cord. /forums/images/graemlins/crazy.gif

I've got welder outlets on three walls in the shop area so I ought to be OK with a shorter cord there and to get outside a little ways. The longer one probably wouldn't get much use but would sure be nice to have 'just in case.' /forums/images/graemlins/smile.gif

Thanks for all of the help, everyone. It's really great getting answers to what I ask and questions I should have asked answered as well. /forums/images/graemlins/blush.gif /forums/images/graemlins/wink.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

 

[hazmat]

<font color="blue"> Hope no one misinterpreted what I did. </font>

Somebody's got to keep you Electrical Engineers in line /forums/images/graemlins/smirk.gif. Who better than a Mechanical Engineer? /forums/images/graemlins/tongue.gif

Re-reading my post, I don't think I articulated my point well /forums/images/graemlins/blush.gif. Gary doesn't need to make any assumptions regarding the efficiency of his welder as the manufacturer has already provided him the info he needs. The owner's manual will state that the welder needs a 240V X amp circuit. Don't know if X is 30amps or 40 amps.

You are correct, the tables assume copper wire.

 

[djradz]

Well Stephen, seeing your in the NH family, I won't be too rough on ya. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif You ME's are always stepping out of line though, trying to equate water flowing in a pipe to electricity. You are certainly right concering efficiency, I hadn't noticed the manual said use a 30 amp circuit. Even at that though, the max draw is probably more like 25 amps (based on my highly accurate electrical engineer's back of the napkin calculation.) Manufacturer probably had no choice to specify 30 amp breaker since it's over the next smaller size, ie 20 amps.

On a more serious note, I hope he pays attention to the limitations of aluminum (oh boy, here we go again, getting into that ME stuff) since the existing wiring in the wall is probably that rather than copper.

 

[Gary_in_Indiana]

<font color="blue"> Don't know if X is 30amps or 40 amps.
</font>

I assume that X = 30 amps since I'm using a 30 amp breaker per Hobart.

 

[Gary_in_Indiana]

<font color="blue"> the existing wiring in the wall is probably that rather than copper </font>

Actually, I wired/rewired every inch of this barn and I can assure you that there is absolutely no aluminum anywhere from the top of the weatherhead in. I can't speak to what the utility company did. /forums/images/graemlins/smile.gif I just know that all of my work was with 12 and 10 gauge copper. I involved the local electrical inspector in the planning stages and, of course, got some help from Inspector 507 here. /forums/images/graemlins/wink.gif

 

[MRHURT]

just going to throw my 2 cents in here

i saw where somebody had mention using so cord, if you do use this remember that so has to be derated. 10/3 so is only rated for 25 amps. 8/3 so is rated for 35. not that much bigger of a cord. like i said just my 2 cents /forums/images/graemlins/smile.gif

 

[Inspector507]

If it's 10/3 SO, thats only 2 current carrying conductors. Under subheading B of Table 400.5(A) of the 2002 NEC®, it is good for 30 Amps.

 

[MRHURT]

i am not disputing the nec, but i was going by the manufactuers rating. Anixter happens to be the brand so cord we use.

 

[Inspector507]

In that case...........manufacturers installation instructions prevail...... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif