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Old 11-26-2008, 05:19 PM   #1
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Grounding an ungrounded exterior circuit


I have a circuit that I inherited from the previous owner of my property that is ungrounded (among other things).

The circuit run is approximately 200 ft in length and is run underground in PVC conduit. The conductors are individual #12 multi-strand conductors. There are two hots and two neutrals. The only thing that this circuit will be used for is to run low-voltage lighting on a newly installed bridge.

1. How can I safely (and easily) ground this circuit without digging it up and starting over? I'm on a tight budget, so can't really afford a do-over.

2. Can a set a 8' grounding rod just for this receptacle?

3. I've read in other threads that the addition of a GFCI at the beginning of the run would make it a "little" safer. Is this true?

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Old 11-26-2008, 05:25 PM   #2
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Grounding an ungrounded exterior circuit


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Originally Posted by Randell Tarin View Post
I have a circuit that I inherited from the previous owner of my property that is ungrounded (among other things).

The circuit run is approximately 200 ft in length and is run underground in PVC conduit. The conductors are individual #12 multi-strand conductors. There are two hots and two neutrals. The only thing that this circuit will be used for is to run low-voltage lighting on a newly installed bridge.

1. How can I safely (and easily) ground this circuit without digging it up and starting over? I'm on a tight budget, so can't really afford a do-over.

2. Can a set a 8' grounding rod just for this receptacle?

3. I've read in other threads that the addition of a GFCI at the beginning of the run would make it a "little" safer. Is this true?
No ground rod!

You either get 200 ft of fish tape, push it through, and pull a 12 awg ground wire. Or you could just put a gfci in, get one rated for WET and DAMP locations.

The gfci is much easier-it is the only way to add a three prong plug to an ungrounded circuit when there are no other ways (like metal conduit, etc.)

You can't tape over one of the wires with green tape.


Last edited by rgsgww; 11-26-2008 at 05:27 PM.
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Old 11-26-2008, 05:25 PM   #3
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Grounding an ungrounded exterior circuit


Are these two different circuits? How is it connected at the breaker box? If there are four conductors run to the box you can make a multiwire branch circuit and have two circuits sharing the neutral and still have a ground. Do not drive a ground rod.

Last edited by jerryh3; 11-26-2008 at 05:33 PM.
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Old 11-26-2008, 05:32 PM   #4
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Grounding an ungrounded exterior circuit


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If there are four conductors run to it, there should be two hots, a ground, and a neutral. How is it connected at the breaker box? Do not drive a ground rod.
There are two black wires and two white wires. All of them are insulated and multi-strand. I didn't think I could use a multi-strand for the ground. They're not connected at the panel yet. This circuit came from the original panel that was on the property. I up-sized when we built our home several years ago and just never reconnected this circuit.

Last edited by Randell Tarin; 11-26-2008 at 05:35 PM.
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Old 11-26-2008, 05:34 PM   #5
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Grounding an ungrounded exterior circuit


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Originally Posted by Randell Tarin View Post
There are two black wires and two white wires. All of them are insulated and multi-strand. I didn't think I could use a multi-strand for the ground.

You could pull a ground, but it might just be easier and cheaper just to put a gfci in. Make sure its rated for wet and damp locations (not all gfcis are)
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Old 11-26-2008, 05:36 PM   #6
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Grounding an ungrounded exterior circuit


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Originally Posted by Randell Tarin View Post
There are two black wires and two white wires. All of them are insulated and multi-strand. I didn't think I could use a multi-strand for the ground. They're not connected at the panel yet. This circuit came from the original panel that was on the property. I up-sized when we built our home several years ago and just never reconnected this circuit.
Yes, you can use stranded for the ground. You would only need three of the wires(hot, nuetral, ground). Technically, this violates code because of the conductor color identification, but ...

Last edited by jerryh3; 11-26-2008 at 05:50 PM.
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Old 11-26-2008, 06:33 PM   #7
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Grounding an ungrounded exterior circuit


I agree that you should just use one of the wires as a ground. Sure it is a technical violation to re-color wire smaller than #4, but I think that is just so the wire manufacturers can sell colored wire. Place the two black wires on a double pole 20 A breaker, put one white wire on the neutral, and tape or color the other one green. Be sure to identify it at both ends.

Using a GFCI receptacle is still a good idea. But it is not a replacement for a real ground, especially since you have enough wires to have a ground. I think it would be down right silly to use a GFCI and leave the circuit ungrounded if a means exists to ground it, since the only violation is coloring a white wire green! Ohhhh...

Ideally, you would upsize the wire for voltage drop and pull the right colors in. But if you are on a budget, just use one of the wires as a ground.
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Old 11-26-2008, 07:02 PM   #8
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Grounding an ungrounded exterior circuit


I was under the impression that code allows for taping or coloring wires a different color. Isn't this practice used commonly in multi-wire switch systems, and if you have a 220V receptacle aren't you allowed to tape the white wire at each end of the run with black tape?

I would not worry about a simple and safe code violation here. Your benefit of having the ground outweighs the code violation by so much it's almost funny!
About the only thing I wouldn't like is 200 ft of #12 wire, but I wouldn't be pulling new wire either, unless the load was very heavy.
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Old 11-26-2008, 07:16 PM   #9
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Grounding an ungrounded exterior circuit


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I was under the impression that code allows for taping or coloring wires a different color. Isn't this practice used commonly in multi-wire switch systems, and if you have a 220V receptacle aren't you allowed to tape the white wire at each end of the run with black tape?

I would not worry about a simple and safe code violation here. Your benefit of having the ground outweighs the code violation by so much it's almost funny!
About the only thing I wouldn't like is 200 ft of #12 wire, but I wouldn't be pulling new wire either, unless the load was very heavy.
You're allowed to re-identify the white as a "hot" in that size range. Multiwires usually use black/red/white so no changes are needed.
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Old 11-26-2008, 07:37 PM   #10
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Grounding an ungrounded exterior circuit


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Originally Posted by KE2KB View Post
I was under the impression that code allows for taping or coloring wires a different color. Isn't this practice used commonly in multi-wire switch systems, and if you have a 220V receptacle aren't you allowed to tape the white wire at each end of the run with black tape?

I would not worry about a simple and safe code violation here. Your benefit of having the ground outweighs the code violation by so much it's almost funny!
About the only thing I wouldn't like is 200 ft of #12 wire, but I wouldn't be pulling new wire either, unless the load was very heavy.
Thanks for all the responses guys! Like I said, the only thing on it will be a transformer for low-voltage lighting, so the load is inconsequential. Wouldn't having the two black wires on one breaker be the same as up-sizing the conductor? If so, that would answer any concerns about voltage drop, wouldn't it?
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Old 11-26-2008, 07:43 PM   #11
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Grounding an ungrounded exterior circuit


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Originally Posted by Randell Tarin View Post
Thanks for all the responses guys! Like I said, the only thing on it will be a transformer for low-voltage lighting, so the load is inconsequential. Wouldn't having the two black wires on one breaker be the same as up-sizing the conductor? If so, that would answer any concerns about voltage drop, wouldn't it?
Do not put both blacks on one breaker. You have two options:
1. Single circuit. Use one black, one white as the neutral, and the other white as the ground. Other black should get capped on both ends.
2. Multiwire(two ciruits to that box). Use both blacks. One to each pole of a two pole breaker. One white for the neutral, and the other for the ground. If you choose this way let us know and we'll explain how to seperate the circuits at the box.

Last edited by jerryh3; 11-26-2008 at 07:47 PM.
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Old 11-26-2008, 08:26 PM   #12
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Grounding an ungrounded exterior circuit


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Do not put both blacks on one breaker. You have two options:
1. Single circuit. Use one black, one white as the neutral, and the other white as the ground. Other black should get capped on both ends.
2. Multiwire(two ciruits to that box). Use both blacks. One to each pole of a two pole breaker. One white for the neutral, and the other for the ground. If you choose this way let us know and we'll explain how to seperate the circuits at the box.
Since I have this set up, how WOULD I separate the two circuits? I can always have a double gang box with two outlets.
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Old 11-26-2008, 09:25 PM   #13
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Grounding an ungrounded exterior circuit


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Since I have this set up, how WOULD I separate the two circuits? I can always have a double gang box with two outlets.
Each black is the hot for it's own circuit. You would pigtail the neutral and ground and feed each circuit with it's own neutral and ground.
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Old 11-27-2008, 08:50 AM   #14
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Grounding an ungrounded exterior circuit


If the only thing you are using this circuit for is low voltage lighting: put the transformer in the house next to panel and use existing wires (almost any combo you like-ie: double up blacks and whites to get lower voltage drop) to extend low votage out to using location.
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Old 11-27-2008, 09:49 AM   #15
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Grounding an ungrounded exterior circuit


If you put the transformer for 12 volts in the house and use both the blacks for the low voltage hot lead out and both the whites for the neutral, then if you draw about 6-1/2 amps out at the bridge, you lose two volts or 17% of the energy in the wires.

6-1/2 amps at 12 volts is about 80 watts.

1000' of 12 gauge wire: 1.6 ohms.
400' (round trip in your situation) 0.6 ohms.
double up the wires: 0.3 ohms
Voltage lost in wires equals current times resistance of the wires.


Last edited by AllanJ; 11-27-2008 at 09:53 AM.
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