Wiring an extension cord...

[POSJ]

I have a 4 prong dryer outlet and I am trying to wire an extension cord for my Miller 211. I can't find any real info on how to wire the plug up. Using 30' 10/3 with a 4 prong to the wall and NEMA 6-50 female connector at the other end. O the 4 prong side the green. Goes to the round plug, do the white and black go to the flats? Or does one go across from the green? I'm pretty sure across from the green is a neutral but I just want some verification.

 

[garrett83]

Hope this helps

 

[POSJ]

Garret that does help clarify the 4 prong side. I'm pretty sure I wire my 10/3 in relation to your picture: green to copper(top), white to red(left), black to black(right), leaving the white(bottom) empty. Just wanting somebody with more experience than me telling me if I'm right or not.

 

[5-90]

Garret that does help clarify the 4 prong side. I'm pretty sure I wire my 10/3 in relation to your picture: green to copper(top), white to red(left), black to black(right), leaving the white(bottom) empty. Just wanting somebody with more experience than me telling me if I'm right or not.

For 220V, you need four leads, not three.

110V uses one phase line and one return line, 220V uses two phase lines and one return line.

This works because you have two phase lines coming into your house panel, each with 110V potential difference between it and return. The two lines get split off into two 110V busses for most outlets - but you feed a 220V from both busses.

Therefore, you will need either 10/3 WG (with ground) or 10/4 for your extension cord. Yeah, you probably could wire it up without the ground (just use three of the four prongs,) but skipping a ground on something like that makes me twitch...

Typically, X/4 wiring will have RED, WHT, BLK, & GRN conductors - use the RED as a second BLK, use the GRN for ground (match it up to the GRN or NONE lead in the plug,) and the WHT wires match up (return lines.)

 

[POSJ]

5-90, why does my Miller 211 have only 3 prongs? I figure it just runs off of 2 phases of 110 then? How does anyone use a welder off of a 4 prong dryer outlet? Seriously asking, no sarcasm or a-holeness in those questions.

 

[scottmcneal]

Did you buy this new? Do you have the owners manual on this welder? It may show you how it is hooked up.

See if this helps out.This is a 3 wire hook up for a welder, they don't use the com/white just the ground.Which is the same wire if you ask me.Same bar on my panel.
http://www.hotrodders.com/forum/wiring-230v-mig-102535.html#post720743
Hope i did the link right

 

[POSJ]

Did you buy this new? Do you have the owners manual on this welder? It may show you how it is hooked up.

:doh: I didn't even think of that lol...

 

[POSJ]

There wasnt anything in the manual, so I just wired it like I said up top and it worked great and my house is not on fire.

 

[kastein]

If you only need to run the welder, 3 conductor will be fine, just don't use the neutral prong. You MUST use the ground prong obviously.

I would have used something larger than 10awg, 10 is only really good to 30 amps per NEC and will have around 3 volts drop over the full circuit. May not seem like much but it's not going to help anything.

 

[5-90]

5-90, why does my Miller 211 have only 3 prongs? I figure it just runs off of 2 phases of 110 then? How does anyone use a welder off of a 4 prong dryer outlet? Seriously asking, no sarcasm or a-holeness in those questions.

Just like with 110V outlets, you can have a 220V with or without a ground. If it's a three-prong 220V, there's no ground (phase/phase/return.) If it's a four, then there is a ground.

Same as the difference between a 2-pring and a 3-pring 110V outlet - there's just an extra phase line to get the 220V potential.

(We all gotta learn sometime - most people don't know how electrical stuff works. No harm in askin'!)

 

[kastein]

no, if it's three-prong, there is no neutral, it's hot/hot/ground. If it's 4 prong, it's technically a 220/110 drop that would be used for something like a modern electric range that has a digital control panel that runs off 110, and thus needs a neutral, since you aren't supposed to actually return current through a ground except in a fault condition, so it'd be hot/hot/neutral/ground.

EVERYTHING must have a ground. Only things that need it (though NEC is reducing the number of circumstances where you can eliminate it) are required to have a neutral.

 

[5-90]

no, if it's three-prong, there is no neutral, it's hot/hot/ground. If it's 4 prong, it's technically a 220/110 drop that would be used for something like a modern electric range that has a digital control panel that runs off 110, and thus needs a neutral, since you aren't supposed to actually return current through a ground except in a fault condition, so it'd be hot/hot/neutral/ground.

EVERYTHING must have a ground. Only things that need it (though NEC is reducing the number of circumstances where you can eliminate it) are required to have a neutral.

Ah - I was wrong, but it still feels like I was on the right track.

Doesn't make sense tho - how can you eliminate return, and keep earth? Isn't that backwards?

 

[kastein]

For 220 loads there is no return needed - the two hot phases are 180 out of phase, i.e. the supply transformer on the pole is actually a 220 output center tapped transformer with the neutral and ground connected to the center tap. One end goes low, the other goes high, and vice versa. So a 220 load simply wires between the two hots.

If you also need 110 for your control system, you need the neutral, though you can ghetto it (assuming no GFCI breaker) using the ground, but you will get smacked for that if the building inspector catches you.

 

[5-90]

For 220 loads there is no return needed - the two hot phases are 180 out of phase, i.e. the supply transformer on the pole is actually a 220 output center tapped transformer with the neutral and ground connected to the center tap. One end goes low, the other goes high, and vice versa. So a 220 load simply wires between the two hots.

If you also need 110 for your control system, you need the neutral, though you can ghetto it (assuming no GFCI breaker) using the ground, but you will get smacked for that if the building inspector catches you.

Ah. I thought they were 180* out WRT the return line, not WRT earth. That was the mental block...

Thanks!