Wiring subpanel

[Mac25]

Mac it''s not ground . It's a neutral . Tell me what current is flowing through the wire and bar? As for your panel it is antiquated and dangerous so change it out . Show me your electrical credentials .

I am not here doubting anyone, just trying to gain some knowledge on the situation. Very seriously doubt the panel is outdated since the home was constructed less than 10 years ago, but I guess I'll change it since you apparently have some kind of special electrical credentials.

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[GPintheMitten]

I think your description of the house panel created some doubt about it meeting code. If a licensed electrician installed it 10 years ago it's probably ok. It might just be a matter of terminology.

Still, if you have any doubt ask the inspector to take a look at it.

Moss oak provided a good diagram. Study it and then talk to the inspector about your project. He may allow you to run another 2 awg to have a 2 2 2 4 wire to feed the barn panel. The 4 is for ground, the others are for each hot lead and neutral. If your using aluminum use a dielectric grease like no ox on yoyr connections to prevent corrosion

 

[GPintheMitten]

Sorry, the diagram was from MossRoad, not moss oak.

 

[yelbike]

That is at odds with NEC code. The neutral-ground bonding should only happen in one place downstream of the main service entrance, and that is at the main breaker panel. All other sub panels fed from the main panel, whether in the same building or in out buildings, should not bond neutral and ground.

I think there is a lot of confusion about ground (and probably neutral). Really, the ground circuit has a couple purposes. One is as a chassis ground, to return any shorted current back to neutral (at that single bonding point). It's like a backup return path to the main service entrance. Another is to serve as an earth ground for stray/excess current that is not part of the normal service (lightning strikes, wiring errors, etc). Rather than think about all the scenarios and second guess things, I just stick to code.

I realize NEC and cec are different but after some discussion and thought this is what I come up with.

You can run 3 conductors from the main entrance and than install another ground source at the outbuilding. Ground source would be two driven rods or a plate. In this installation you would leave the neutral to ground jumper installed.

Or.

You can run 4 conductors to the outbuilding. Now there's no need for a second ground source. In this case you'd remove the neutral to ground jumper.

Credentials: "M" licensed electrician, unrestricted "HE" licensed electrician and power electrician (utility). This still doesn't make me an engineer.

 

[JPRambo]

You can run 3 conductors from the main entrance and than install another ground source at the outbuilding.
Or.

If by "main entrance" you mean "meter can" I agree. If after meter I disagree. At least here in sunny Florida you must separate the neutral and ground after the first disconnect (main breaker)

 

[Inspector507]

The NEC used to permit running 3 wires to a second structure and ground the neutral there. It has since changed and requires 4 wires. You need to have a grounding electrode at the second building tied to the ground bar. No neutral bonding jumper.

 

[MossRoad]

Sorry, the diagram was from MossRoad, not moss oak.

Hey, it all grows on the north side!!! :laughing:

 

[Mac25]

The NEC used to permit running 3 wires to a second structure and ground the neutral there. It has since changed and requires 4 wires. You need to have a grounding electrode at the second building tied to the ground bar. No neutral bonding jumper.

So amongst all the confusion, I am going to return my 2-2-4 wire, purchase 2-2-2-4, run two hots, neutral and a ground to my barn panel, unbond the neutral and ground there, install another ground on the ground bar leading to a couple grounding rods. Sound like it should work?

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[GPintheMitten]

So amongst all the confusion, I am going to return my 2-2-4 wire, purchase 2-2-2-4, run two hots, neutral and a ground to my barn panel, unbond the neutral and ground there, install another ground on the ground bar leading to a couple grounding rods. Sound like it should work?

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That's what I would do. But I would still pull a permit and get an inspection.

 

[MossRoad]

That's what I would do. But I would still pull a permit and get an inspection.

Yep. Because if your house burns down, your insurnace may not cover it.

 

[yelbike]

So amongst all the confusion, I am going to return my 2-2-4 wire, purchase 2-2-2-4, run two hots, neutral and a ground to my barn panel, unbond the neutral and ground there, install another ground on the ground bar leading to a couple grounding rods. Sound like it should work?

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Yes, that will work just fine. An inspection is always a good idea. The extra ground rods wouldn't be required. But if your going to have cattle in the burn than you really can't have too much grounding. They can be very sensitive.

I have never personally seen an instance where an insurance company denied a claim because a permit wasn't pulled even if required. To be denied a claim you'd have to blatently and purposely do something wrong.

 

[STx]

The NEC says that subpanels are to have isolated grounds so the answer is unless there's a local code that dictates otherwise, the proper way is to not bond the neutral at the sub-panel and to install a separate 8', copper clad ground rod.

When installing the ground rod, it should be driven diagonally into the ground, closer to horizontal than vertical.

From the feeder panel, you will run 2 hots and a neutral, you do not need a 4th wire. I missed it if you indicated the length of the run so I can't comment on the wire size and voltage drop.

 

[GPintheMitten]

The NEC says that subpanels are to have isolated grounds so the answer is unless there's a local code that dictates otherwise, the proper way is to not bond the neutral at the sub-panel and to install a separate 8', copper clad ground rod.

When installing the ground rod, it should be driven diagonally into the ground, closer to horizontal than vertical.

From the feeder panel, you will run 2 hots and a neutral, you do not need a 4th wire. I missed it if you indicated the length of the run so I can't comment on the wire size and voltage drop.

This is totally wrong. You need to run a ground wire from the main panel to the sub. Keep ground and neutral separate at the sub and put in a ground rod at the sub as well.

 

[STx]

And connect the ground wire from the feeder panel to what? If you connect it to your isolated ground, then you've effectively bonded the sub=-panel ground and neutral at the feeder panel and eliminated the isolated ground at the sub-panel...

 

[s219]

GP is correct -- run ground wire to sub panel, install ground rod(s) at sub panel, and do not bond neutral to ground at sub panel. The only bonding should be at the main panel, which is the point where the entire ground system could/would be passing stray current back to neutral.

Panels always have a strap or lug between ground and neutral that allow them to be bonded or unbounded. As a main they would be bonded. As a sub, no.

 

[GPintheMitten]

And connect the ground wire from the feeder panel to what? If you connect it to your isolated ground, then you've effectively bonded the sub=-panel ground and neutral at the feeder panel and eliminated the isolated ground at the sub-panel...

Connect it to what?:

The ground wire that runs between the main and the sub is connected in the main to the ground buss which is, or should already be, bonded to the neutral in the main. The ground wire at the sub is connected to the ground bus which is not bonded to the neutral in the sub. The ground wire bus in the sub is also connected to grounding rod(s) buried near the sub with a ground wire.

Your inspector will verify this info and verify the installation. I always get and recommend a permit and inspections for installing main or sub-panels.

 

[STx]

So again, you've effectively bonded the ground and neutral in the sub-panel. Draw it on paper and you'll see what I'm saying. This is not an isolated neutral. It'll functionally work but can cause issues with sensitive electronics, both in the house or in the barn.

 

[GPintheMitten]

So again, you've effectively bonded the ground and neutral in the sub-panel. Draw it on paper and you'll see what I'm saying. This is not an isolated neutral. It'll functionally work but can cause issues with sensitive electronics, both in the house or in the barn.

The way I described it follows code. The way you described it violates code.

Yes, the neutral wire is connected electrically to ground at the main. That doesn't change the need to follow code.

 

[STx]

I absolutely agree that the code should be followed and if what you're saying is correct, I've misread code. I understand NEC to call for an isolated ground and have installed it as I described more than once with the advice and supervision of a licensed electrician and it always passed inspection...

 

[aczlan]

I absolutely agree that the code should be followed and if what you're saying is correct, I've misread code. I understand NEC to call for an isolated ground and have installed it as I described more than once with the advice and supervision of a licensed electrician and it always passed inspection...

Current NEC code (2011) requires that the neutral and the ground be run separately from the subpanel back to the main panel and that the neutral/ground only be bonded at the main disconnect.
Previously (before the 2011 revision of the NEC code), it was permitted to have 3 wires going from the sub panel(s) back to the main panel.

Aaron Z