220A welding circuit question

[dstig1]

All the more reason to use the white wire for the neutral. You've got two 6 ga wires supplying power and one wire half that size for the return. No good in my experience.

Ian

Ian, I think you are confusing two points here. The neutral is not the same as the ground. In the main panel, yes, they are tied together so at the same potential (ground) but the code is written so that the neutral is a "current carrying conductor" but the ground is not. The only time the ground wire should ever carry any current is during a short, and then the purpose is for it to return that current to the panel so it trips the breaker (and keeps the case of the tool/appliance from being energized). The neutral always carries current on a 120v circuit in use, and will sometimes carry current in a 4-wire 220V circuit (like a stove or modern dryer) as it will be used for 120V accessories like the timers. Welders don't generally have any 120v items so they just use 2 hots and one ground - no neutral.

 

[wstf2]

in upper right of picture he indicates his ground properly hooked to the ground buss strip

I think someone else wired the outlet, they used 3+ ground so white is xtra

Correct, two different electricians.

 

[wstf2]

I think you need to back up a little. First off you're talking a sub-panel. In a sub-panel the neutral wires and ground wires can't be connected. Or to be more correct the neutral wires and ground wires are only to be connected in the main panel.

Your outlet has three connectors. Two hot, those would be your red and black wires in your sub panel and a ground. That needs to be connected up to the terminal strip that the bare ground wire connects to in your sub panel.

I missed something about the white wire, I'll reread and try and figure out what I missed. Are you talking about the white wire coming in from the main breaker or are you talking about a white wire in the wire you used to wire up the outlet.

Yes, that white wire. See the sub panel photo in my opening post and the white wire/green arrow from the outlet below.

 

[crazyal]

I'm not sure what the code requires but if the white wire is not used I would either put a wire nut on each end or cut it off flush where it comes into each box (not sure if that's allowed by code though but it's often what I do).

 

[Transit]

Ian, I think you are confusing two points here. The neutral is not the same as the ground. In the main panel, yes, they are tied together so at the same potential (ground) but the code is written so that the neutral is a "current carrying conductor" but the ground is not. The only time the ground wire should ever carry any current is during a short, and then the purpose is for it to return that current to the panel so it trips the breaker (and keeps the case of the tool/appliance from being energized). The neutral always carries current on a 120v circuit in use, and will sometimes carry current in a 4-wire 220V circuit (like a stove or modern dryer) as it will be used for 120V accessories like the timers. Welders don't generally have any 120v items so they just use 2 hots and one ground - no neutral.

Yes Dave, I said the same thing.

 

[Transit]

What is going on? The photo in post # 1 is not the same as the original photo, the input feeds led were black and there was a bare heavy gauge ground led, now the led are colored.
In an other post it talks about the utility feed to the building being Red, Black, Blue, Ground and Neutral. That is very unusual to have 3 phase power to a home.

 

[speedy2]

Fellows, I'm not a electrican but if the green arrows indicate that the black and red wires in the picture are to be used to feed the welder should'nt one of them be on the other hot leg and on the same one? Just asking! Speedy2

 

[CharlieS]

After almost 40 years in the trade, of which 30+ are as a licenced master electrician, right off i notice two NEC violations in the OP's image posted.
Even though this is single phase, and as such generallly overlooked by inspectors, NEC requirements for color coding are black-red-blue when viewed from left to right, top to bottom or front to back. The only time NEC allows a change in phasing colors is in the case of three phase, where two wires need to be exchanged on terminals to reverse a motor rotation.
The second is definately a danger issue as it can potentially create back feed to the main panel in case of a fault.
For a sub panel, neutral and ground bar's may NOT be tied together. (A main panel its permissible and in most cases requiered.)
In this case the tie bar at the bottom of the panel needs to be removed, ALL white neutral conductors must be tied under the neutral bar on photo right, while all ground wires must be connected to the isolated ground bar photo left. This is called floating the neutral.
Grounded conductor can be either solid or stranded wire, bare or insulated with green or green/w yellow stripe insulation, and must be a minimum #8 in size, though most juristictions i've worked in now require a minimum #6. Any conductor smaller than a #6 cannot be taped green, it must have an insulating coating of the proper color, or be stripped to expose bare wire. The main grounding conductor needs to be attached to a minimum 1/2 x 8' copper or copperclad ground rod or 5/8 x 8 galvinized rod. IF there is water suppled to the building, a cold water ground is also necessary as is bonding any building steel, in the case of a steel building.
That being said, in the case of a 240v welder, two power conductors and a ground are all thats needed generally to safely power and protect the equipment. The ground or equipment ground protects from shock hazard while the two current carrying conductors, (in a 240 volt application) will carry the load imbalance back to the panel for each other.
In the case of a 120v outlet, the white or neutral conductor is what carries said load imbalance back to the panel completing the circuit.

 

[CharlieS]

Fellows, I'm not a electrican but if the green arrows indicate that the black and red wires in the picture are to be used to feed the welder should'nt one of them be on the other hot leg and on the same one? Just asking! Speedy2

@ speedy2
no because of the configuration of the attachment lugs in the panel a two pole breaker such as seen in the photo, the breaker is attached to one lug of each phase by default.

 

[rus_geek]

In this case the tie bar at the bottom of the panel needs to be removed, ALL white neutral conductors must be tied under the neutral bar on photo right, while all ground wires must be connected to the isolated ground bar photo left. This is called floating the neutral.

This is getting a little OT, but this is incorrect for this panel type. The two bars tied together across the bottom are both neutrals. There is a third bar in the upper right for the grounds. That one is bonded to the panel, while the other two are isolated from it.