Wiring up my 250ex

[dgarnier]

For 220-240V 2-phase operation, follow the instructions given previously:

Machine BLACK to wall BLACK
Machine WHITE to wall RED
Machine GREEN to wall BARE (GREEN)
Machine RED and wall WHITE are not used

The green machine wire is connected to the welders chassis, so it must be connected to the grounded conductor, normally bare. In a 2-phase system, one of the hot wires always acts as a return for the circuit, so there is not a common/return wire. The ground wire is for safety, and for chassis noise reduction, so while a 10AWG would work for the noise aspect, it may not be able to handle the current draw before the breaker tripped if a short to chassis were to occur. Plus I am pretty sure the NEC requires the same size wire - I can look it up if you want.

Ken

Ok so from the main pannel I could use 2 6awg wires(white and black) that are comming off 50amp 2 pole breaker for the 2 hots. Then hook up the green wire to ground which is hooked up to the to the box the outlet is wired to so the conduit will then carry the current is something goes wrong. Does this sound right?

[dgarnier]

What that paragraph is really trying to say is that 2 hot wires from the same phase would measure 0 VAC across them, so your box wouldn't work. Two hot wires from the opposing phases would generate 220/240 VAC so everything will work, and any hot measured to either neutral/return/ground would be 110/120 VAC...

ok that helps me understand 220...now I see why 220 is not sright forward as 110.

[kenwhite]

Ok so from the main pannel I could use 2 6awg wires(white and black) that are comming off 50amp 2 pole breaker for the 2 hots. Then hook up the green wire to ground which is hooked up to the to the box the outlet is wired to so the conduit will then carry the current is something goes wrong. Does this sound right?

You can use the conduit if your local code allows its during retrofit. I believe all new installations require a seperate ground wire.

[PinkNinja]

Thank for all your replies!

She fired up beautifully! Couldn't be happier!

[A/C Guy]

ok now things are starting to add up in my head...so you could hook up a single phase 220 welder with just 2 hot wires and then tie the ground wire from the welder to the box/conduit? If this is the case, and I dont trust the box/conduit as a ground and I want to run a ground wire would it have the be the same gauge as the 2 hot wires(6awg)? or could I use a 10awg for the ground wire?

First part, Yes if they are opposite legs. You can verify by using a volt meter. If your meter shows < 100 volts, you probably are connected to the same leg of 110 on each line. I only mention this because I have see old boxes that wee mis-wired.

National Electric Code allows 10 gauge wire to be used for ground on circuits up to 60 amps. After 60 amps, the ground needs to be 8 gauge. Be sure to buy green wire or green electrical tape and mark the wire clearly with the green tape.

Although some locales allow using conduit for the ground, it is a very, very bad practice. I have seen the damage caused by that practice. Just last week, I was almost zapped when a machine went short to ground and the conduit was not properly bonded to the boxes at either end. The installer used #14 ground, it melted before the breaker tripped. The conduit was visibly vibrating and the arcs sounded just like a MIG running spray mode (240 volts at over 200 amps is some serious spray mode weld action).

[A/C Guy]

For 220-240V 2-phase operation, follow the instructions given previously:

There is no such thing as 2 phase.
Single phase is 2 legs of 120 A/C in opposite phase of each other.
Next is 3 phase, where we have 3 legs of 120, 60˚ apart. Phase to phase voltage on each is 240 (or more commonly 208). Phase to ground is 120 volts. Phase to neutral is 120 volts.

You can use the conduit if your local code allows its during retrofit. I believe all new installations require a seperate ground wire.

See my previous post as to why this is a very bad thing to do.

Also, code requires the ground wire to be a continuous circuit and must be inside the conduit; not piggy backed on the outside. No daisy chaining allowed either.

[A/C Guy]

Ok so from the main pannel I could use 2 6awg wires(white and black) that are comming off 50amp 2 pole breaker for the 2 hots. Then hook up the green wire to ground which is hooked up to the to the box the outlet is wired to so the conduit will then carry the current is something goes wrong. Does this sound right?

IF, and only if the machine requires a 50 amp circuit. If the machine requires, less than use the proper breaker. If you are doubling on a circuit such as the kitchen stove, then you must run the proper size wire for the breaker (same as the stove) to a fused box for the welder.

i.e. If the welder only needs 30 amps and you are tying into the stove circuit (50 amps), you run the #6 wire with ground to a $10 fused box that you mount on the wall for the welder. The fused box would be a 30 amp box since that is the size of fuse required by the welder. (60 amp boxes and fuses are larger, so they are not interchangeable.) From the new 30 amp FUSED box, run #10 wires with ground to the new receptacle for the welder.

If the welder requires 40 amp protection. Same scenario. Run #6 wire with ground from stove circuit to new $10 fused disconnect box. This time we use a 60 amp fused box, but with 40 amp fuses. (The 60 amp rating just means the box is rated for 35 to 60 amp fuses.) Now we run #8 wires plus ground from our new 60 amp box (with the 40 amp fuses) to our new receptacle that is mounted on the wall for the welder.

As a last option. With either above set up, we can substitute a long, heavy duty, black #10 (for 30 amp) or #8 (for 40 amp) power cord with a female plug instead of the wall mounted receptacle. That allows you to move the welder around instead of having to be tied to the wall mounted receptacle. That is what I did in my shop. This is legal in commercial and residential environments.

[dgarnier]

ok thanks for all the help guys, got some 10awg green wire that I am going to pull later tonight and get the new outlet for the welder all buttoned up tonight

[kenwhite]

There is no such thing as 2 phase.
Single phase is 2 legs of 120 A/C in opposite phase of each other.
Next is 3 phase, where we have 3 legs of 120, 60˚ apart. Phase to phase voltage on each is 240 (or more commonly 208). Phase to ground is 120 volts. Phase to neutral is 120 volts.

See my previous post as to why this is a very bad thing to do.

Also, code requires the ground wire to be a continuous circuit and must be inside the conduit; not piggy backed on the outside. No daisy chaining allowed either.

A 220/240 VAC center tapped transformer produces 2 voltages 180 degrees out of phase with each other, so technically this is a 2-phase system.

3-Phase systems have each voltage 120 degrees out of phase with each other, not 60 degrees.

While using conduit is not allowed for new installations, some locallities allow it for retrofit installations...

[Rivets]

A 220/240 VAC center tapped transformer produces 2 voltages 180 degrees out of phase with each other, so technically this is a 2-phase system.

[snip]

Ken, with all due respect,

1- If the voltages were 180 degrees out of phase, then the resulting voltage would be zero.

2 - Technically, it's called a Split Phase system.

Cheers,
Rivets

[kenwhite]

Ken, with all due respect,

1- If the voltages were 180 degrees out of phase, then the resulting voltage would be zero.

2 - Technically, it's called a Split Phase system.

Cheers,
Rivets

Rivets, with all due respect, if the voltages are in phase with each other, then the voltage would be zero...

Opposing phase or split phase phase is still a circuit with both voltages 180 degrees out of phase, or 2 different phases, or 2-phase..

[performance]

Rivets is right. Its single,split phase... There is 2 phase systems out there, albeit they are older and fading away in this country. I think the last two phase systems may be in NY state.

[kenwhite]

Rivets is right. Its single,split phase...But AC guy is wrong. There is 2 phase systems out there, albeit they are older and fading away in this country. I think the last two phase systems may be in NY state.

Mark, if the secondary of the step-down transformer is center-tapped, it produces 2 branches each 180 degrees out of phase with each other when referenced to the center tap..

So while we call it single phase when running line-line, it is technically a 2-phase system when run line-neutral.

You guys can call it anything you want, but it behaves exactly as I have described it.

[DiabolicZ]

Ok, I am confused by there being two legs, and wiring into each one.

My stove has a 50 amp breaker (thought it was higher) with two ports for wires. Each of those ports is for one single 110v line. Two of them together equals 220v.

I have my welder currently wired into that one single breaker. One white wire going to one side of the breaker and one black wire going to the other. Then the green is ground. My welder works fine however. Did I still wire it up wrong?

When I hear you guys talk of "legs" I am thinking of one singe 110v breaker on one side of the box and then another 110v breaker on the other side of the box. I have two main power wires (legs?) coming into my box and they each power their own side of the box (at least that's what it looks like).

It does not seem right to have a welder running on two separate 110v breakers and I'm pretty damn sure that is NOT what you guys are talking about right?

[kenwhite]

Ok, I am confused by there being two legs, and wiring into each one.

My stove has a 50 amp breaker (thought it was higher) with two ports for wires. Each of those ports is for one single 110v line. Two of them together equals 220v.

I have my welder currently wired into that one single breaker. One white wire going to one side of the breaker and one black wire going to the other. Then the green is ground. My welder works fine however. Did I still wire it up wrong?

When I hear you guys talk of "legs" I am thinking of one singe 110v breaker on one side of the box and then another 110v breaker on the other side of the box. I have two main power wires (legs?) coming into my box and they each power their own side of the box (at least that's what it looks like).

It does not seem right to have a welder running on two separate 110v breakers and I'm pretty damn sure that is NOT what you guys are talking about right?

For most homeowners, the electric utility company provides 3 wires to the house service entrance from a step-down transformer that is center tapped.

What this means is that there are 2 possible voltage levels present on these 3 wires - 120 or 240 VAC.

The 3 wires are typically called hot-neutral/return-hot or line-common-line or other names that the electrician has learned in his trade.

A leg or phase is a hot line referenced to a common point (ground) - in a typical household system, there are 2-120 VAC hot lines, each 180 degrees out of phase with each other, referenced to the common wire.

So when you measure across one phase (line-common), you get 120VAC, measure across the other phase (line-common), you get 120VAC. and when you measure across both phases (line-line), you get 240VAC - these voltage values are called the effective voltage (RMS) values and are not the instantaneous value that allows the phase angle/time shift to be seen - as a side note, the peak voltage present in a 120 VAC system in 170V...

So, to answer your question, some equipment needs/uses 4-wires (line-common-ground-line) since it requires both 120VAC and 240VAC - some stoves, dryers, etc...

The welder only uses 240VAC, so it needs 3-wires (line-ground-line), however if you were to measure the voltage from either line-ground, you would see 120VAC, so it is technically running on 2-120VAC lines

Based on your description, everything appears to be wired correctly at your service panel.

[DiabolicZ]

The welder only uses 240VAC, so it needs 3-wires (line-ground-line), however if you were to measure the voltage from either line-ground, you would see 120VAC, so it is technically running on 2-120VAC lines

Thank you, this makes perfect sense then. When my water heater breaker popped, only half of it popped some how (single 120v side), but the whole breaker still looked like it was on. I was measuring voltage to the water heater and saw 120v everywhere. I was confused as to why I did not see 240v. After a while of chasing my tail, I figured out only half of the breaker popped. Since the other side did not pop, it didn't let the side that DID pop move that far to tell it had been tripped.

Basically, I understand 120 + 120 = 240v in a sense. You guys just scared me into thinking I was running my welder off of 120v for the last 5 years LOL.

[Rivets]

Rivets, with all due respect, if the voltages are in phase with each other, then the voltage would be zero...

Opposing phase or split phase phase is still a circuit with both voltages 180 degrees out of phase, or 2 different phases, or 2-phase..

Ken,

If you google "Wave Interference", and select Wikipedia "Interference (wave propagation)" and scroll down to "Constructive and destructive interference", you will find a short paragraph and graphics that clearly show the opposite of what you state.

So, if too voltages of the same frequency and amplitude are 180 degrees out of phase, then the resultant voltage is zero, and not their sum.

Sorry, but that's the physics of it.

Cheers,
Rivets

[kenwhite]

Ken,

If you google "Wave Interference", and select Wikipedia "Interference (wave propagation)" and scroll down to "Constructive and destructive interference", you will find a short paragraph and graphics that clearly show the opposite of what you state.

So, if too voltages of the same frequency and amplitude are 180 degrees out of phase, then the resultant voltage is zero, and not their sum.

Sorry, but that's the physics of it.

Cheers,
Rivets

Rivets, we are not talking about electromagnetic wave theory, though we could if you would like to, but rather voltage and current confined to a physical medium.

If you take your meter and look the the leads, they are red and black to represent (+) and (-) respectively.

This means that when a meter measures voltage across any component, or line pair, that the voltage measured at the black lead is subtracted from the voltage measured at the red lead.

So 120 VAC - (+) 120 VAC (two in phase voltages) = 0 VAC

120 VAC - (-) 120 VAC (two 180 degree out of phase voltages) = 240 VAC

Do an experiment for me: Go to any two outlets that are on the same branch and measure the voltage across both hot legs. What value do you get? If the voltages are on the same branch, they must be the same phase...

Have fun and tell me what happens...

[Rivets]

Rivets, we are not talking about electromagnetic wave theory, though we could if you would like to, but rather voltage and current confined to a physical medium.


1- A wave is a wave. Sound, light or electromagnetic. The interference phenomenon applies equally. You can't change the physics of it.

If you take your meter and look the the leads, they are red and black to represent (+) and (-) respectively.

2- They could be any color. (+) and (-) are irrelevant in AC measurements.

This means that when a meter measures voltage across any component, or line pair, that the voltage measured at the black lead is subtracted from the voltage measured at the red lead.

So 120 VAC - (+) 120 VAC (two in phase voltages) = 0 VAC

120 VAC - (-) 120 VAC (two 180 degree out of phase voltages) = 240 VAC

Do an experiment for me: Go to any two outlets that are on the same branch and measure the voltage across both hot legs. What value do you get? If the voltages are on the same branch, they must be the same phase...

Have fun and tell me what happens...

3- No need to do the experiment. The answer is zero volts of course.
Not because the voltages are in phase, but because you are attempting to measure a voltage by putting your two meter probes on one bus bar.

Cheers,
Rivets

[kenwhite]

Cheers,
Rivets

Rivets, an electromagnetic wave behaves according to wavelength principles applied to Maxwell's equations - forward, reflected, and standing waves...

Waveforms that are much, much, shorter than their wavelength behave quite differently and follow Ohm's, Kirchhoff's, etc, etc, laws.

My explanation is exactly correct.

If you won't do my experiment because you know it all, search for center tapped transformer applications and see how they behave. Then if you have acess to a dual channel oscilloscope, go and measure the 2 hot lines at the same time referenced to the commom/center tap.

Oh, and you can't discount how a meter works just because you are measuring AC...

If you aren't willing to verify what I have said, then I can't help you...

Cheers,