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Can neutral & ground wires touch in main?


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The question is not for a sub panel.

The question is not how many wires can go in one lug hole,

or about grounding rods, or about isolation or bonding.

This concerns the main breaker panel with ground, neutral and box all bonded together.

I mistakenly stripped 6-9 in of the white insulation off the ground wires.

This lets them electrically touch before they terminate in their respective grounding bar lug holes.

That would be a clear no-no for a branch panel, but for a main panel I see no problem.

My wiring did not pass inspection, though, because

NEC says ground and neutral are to be terminated in the grounding bar.

But how literally should this code be read for a main panel?

The grounds and nuttrals aren't "terminated" where they might touch.

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The white wire is a neutral. It carries voltage, on a 120 volt circuit, for example, 120 volts. It should be insulated until it reaches the terminal to prevent arcing in the panel. A bare grounding wire, grounded with no voltage, will short the bare neutral and there will be sparks flying in your panel.

Also you should not have Copper and Al in the same lug.

Also you should not have multiple wires of different gauges in the same lug.

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The neutrals (white) should terminate individually, one under a single screw. This way they can be individually isolated if needed while circuits are being serviced in the house. By stripping the insulation and allowing them to mingle with other neutrals or grounds, you cause complications in being able to isolate them. The following document explains further.

Neutral Isolation

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The white wire is a neutral. It carries voltage, on a 120 volt circuit, for example, 120 volts. It should be insulated until it reaches the terminal to prevent arcing in the panel. A bare grounding wire, grounded with no voltage, will short the bare neutral and there will be sparks flying in your panel.

Just to clarify, that would only happen if you were to disconnect one or more of the neutrals from the terminal bar while there was a load on it. And in that case, you'd get sparking anyway, even if the insulation weren't stripped back. The missing insulation makes the situation worse, though. The neutrals should be reinstalled properly, with insulation right up to the terminal bar. If they're too short, the installer can splice extensions on to them. As it is now, it'll be a nightmare to troubleshoot in the future.

Also you should not have Copper and Al in the same lug.

Also you should not have multiple wires of different gauges in the same lug.

Agreed.

The inspector was right to deny this installation.

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It's hard to imagine that anyone in their right mind would have the breaker on with the black wire connected and then try disconnecting the return (white) wire. That's crazy. But OK, if that's a concern, the white insulation should go all the way to the lug.

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It's hard to imagine that anyone in their right mind would have the breaker on with the black wire connected and then try disconnecting the return (white) wire. That's crazy. But OK, if that's a concern, the white insulation should go all the way to the lug.

Hire an electrician.

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The white wire is a neutral. It carries voltage, on a 120 volt circuit, for example, 120 volts. It should be insulated until it reaches the terminal to prevent arcing in the panel. A bare grounding wire, grounded with no voltage, will short the bare neutral and there will be sparks flying in your panel.

Ummm, no.

Neutrals carry current, not voltage. A bare ground touching a neutral in a panel will NOT throw sparks. Unless of course the neutral is disconnected, then grounding it will only show a load arc if the circuit is on and under a load.

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The white wire is a neutral. It carries voltage, on a 120 volt circuit, for example, 120 volts. It should be insulated until it reaches the terminal to prevent arcing in the panel. A bare grounding wire, grounded with no voltage, will short the bare neutral and there will be sparks flying in your panel.

Ummm, no.

Neutrals carry current, not voltage. A bare ground touching a neutral in a panel will NOT throw sparks. Unless of course the neutral is disconnected, then grounding it will only show a load arc if the circuit is on and under a load.

Oops. My clutch was slipping there. [:)]

But when the neutral is loaded, that current would be shared with any ground wires touching it, no?

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Currents in conductors do not exist without voltages present.

Voltages are generated wherever currents flow in conductors.

But all that doesn't matter to an HI. Mostly what's important is whether there's a nominal voltage present or not, 120 volts or not.

Somewhere, far away, an old curmudgeon of an HI is laughing aloud. [;)]

Marc

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Oops. My clutch was slipping there. [:)]

But when the neutral is loaded, that current would be shared with any ground wires touching it, no?

Definitely not. The current will flow on the conductor only. If the conductor or termination/connection were compromised then it may try and find another path to flow back to it's source.

The only time there will be voltage present on a neutral is again, if the neutral is open and there is a live load on the circuit.

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Oops. My clutch was slipping there. [:)]

But when the neutral is loaded, that current would be shared with any ground wires touching it, no?

Definitely not. The current will flow on the conductor only. If the conductor or termination/connection were compromised then it may try and find another path to flow back to it's source.

The only time there will be voltage present on a neutral is again, if the neutral is open and there is a live load on the circuit.

Mr. Petey, you are saying that AC behaves differently in a panel box than it does in a radio or an appliance? You are an electrician so I will bow to your advanced training. I think we are just miscommunicating. [:)]
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Oops. My clutch was slipping there. [:)]

But when the neutral is loaded, that current would be shared with any ground wires touching it, no?

Definitely not. The current will flow on the conductor only. If the conductor or termination/connection were compromised then it may try and find another path to flow back to it's source.

The current will flow on all available paths. If the bare neutrals in the original post are touching the equipement grounding conductors, then a portion of the current on those neutrals will flow on the EGCs.

The only time there will be voltage present on a neutral is again, if the neutral is open and there is a live load on the circuit.

Agreed. There will be no voltage between the neutral wires and the equipment grounding wires. Those two things will be at the same potential.

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The current will flow on all available paths. If the bare neutrals in the original post are touching the equipement grounding conductors, then a portion of the current on those neutrals will flow on the EGCs.

I agree that it CAN, but I disagree that it definitely will. If the neutral is properly sized and terminated properly there is no reason current would flow on the ground.

Besides, what are we talking about here? 1/4"?

If this were the case then why are bare neutrals allowed in SEU cable?

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The current will flow on all available paths. If the bare neutrals in the original post are touching the equipement grounding conductors, then a portion of the current on those neutrals will flow on the EGCs.

I agree that it CAN, but I disagree that it definitely will. If the neutral is properly sized and terminated properly there is no reason current would flow on the ground.

Besides, what are we talking about here? 1/4"?

If this were the case then why are bare neutrals allowed in SEU cable?

If the current can flow on a wire it will (in proportion to the resistance on the wire). The electricity doesn't know or care where we intend it to flow.

It's more than 1/4". If you look at the picture in the original post, he's stripped the insulation back 7 or 8 inches on some of those neutrals. I don't think that there's any grave danger here, but it's very sloppy work - I've never seen an electrician do work like this and I'll bet that you'd never do work like this. Anyone who has to come back to work on this panel will be frustrated.

As for SEU cables, their bare neutrals are on the supply side of the service. On the load side of the service the bare conductor on SEU shouldn't be used as a neutral, only as an equipment ground. (Since about 1996, no?)

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The white wire is a neutral. It carries voltage, on a 120 volt circuit, for example, 120 volts. It should be insulated until it reaches the terminal to prevent arcing in the panel. A bare grounding wire, grounded with no voltage, will short the bare neutral and there will be sparks flying in your panel.

Ummm, no.

Neutrals carry current, not voltage. A bare ground touching a neutral in a panel will NOT throw sparks. Unless of course the neutral is disconnected, then grounding it will only show a load arc if the circuit is on and under a load.

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Oops. My clutch was slipping there. [:)]

But when the neutral is loaded, that current would be shared with any ground wires touching it, no?

Definitely not. The current will flow on the conductor only. If the conductor or termination/connection were compromised then it may try and find another path to flow back to it's source.

The only time there will be voltage present on a neutral is again, if the neutral is open and there is a live load on the circuit.

[:-thumbu]
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