Electrical box, grounding....

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  #1  
Old 07-20-05, 11:41 AM
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Electrical box, grounding....

Hello,

I have a new electrical that I installed myself. The ground wire (which is attached to a large copper ground rod just outside the house) comes into the box from the top and attaches to a large lug for the ground wire on the left side of the box. The box has two strips for ground wires to attach to, one of the left (where the main ground attaches) one of the right. The two strips are not connected to either with any ground wire. Should I run a ground wire from one strip to the other to ensure the right strip is grounded well. I'm assuming the right strip is grounded because the box is grounded by the ground wire from outside. But would it be better if I were to connect to the two with say a 6 gauge ground wire?

Thanks!
 
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Old 07-20-05, 11:45 AM
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Is this in your main panel?

Did you install the bonding screw or strap in the panel?
 
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Old 07-20-05, 12:02 PM
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Yes, and you also need a ground wire to the metal piping in the house. You may also need another ground source.
 
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Old 07-20-05, 12:26 PM
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Originally Posted by pcboss
Is this in your main panel?

Did you install the bonding screw or strap in the panel?
Yep this is my main panel. It's a 200 AMP Square D panel with room for 40 single pole breakers/20 double pole breakers (I believe). I did not install a strap inside the panel, and after looking at it, I do not see any way in which the two strips are connected other than they are both mounted to the box.

To answer racraft... can you please explain grounding to the plumbing a little more. From what I know most people ground to plumbing usually if they don't have a way to connect to a good ground rod... is this true? The water supply enters the hous through a plastic/rubber hose (some sort of fancy synthetic supply line). So, even if I did ground to the plumbing, would it do me any good? Thanks!
 
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Old 07-20-05, 12:37 PM
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Grounding is complicated and extremely important.

In short, if the piping that enters your house is metal then that piping MUST be the main grounding means for your electrical. Since the piping that enters your house is not metal then this doesn't apply. However, the metal pipes within the house must still be BONDED to the electrical system's ground. This provides a safety path should the the plumbing accidentally become energized in any way by your electrical wiring.

You must have two means of grounding for your panel. Usually a ground bar is one and the plumbing is the second means. In your case you need a second.
 
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Old 07-20-05, 01:46 PM
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Originally Posted by racraft
Grounding is complicated and extremely important.

In short, if the piping that enters your house is metal then that piping MUST be the main grounding means for your electrical. Since the piping that enters your house is not metal then this doesn't apply. However, the metal pipes within the house must still be BONDED to the electrical system's ground. This provides a safety path should the the plumbing accidentally become energized in any way by your electrical wiring.

You must have two means of grounding for your panel. Usually a ground bar is one and the plumbing is the second means. In your case you need a second.
Thanks for the info, much appreciated! I'll work on grounding the plumbing to the box ASAP, and will ponder a second grounding option. Thanks a million!
 
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Old 07-20-05, 03:39 PM
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Sx,

IN regards to grounding the plumbing....make sure you ground it to within 5' from the point of entrance of the water main supply. You can't just ground to any old metal water pipe you see...just wanted to keep you aware of that.
 
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Old 07-20-05, 03:42 PM
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Originally Posted by ElectricalMan
Sx,

IN regards to grounding the plumbing....make sure you ground it to within 5' from the point of entrance of the water main supply. You can't just ground to any old metal water pipe you see...just wanted to keep you aware of that.
Ahhh, that makes sense. Thanks for the info. Also, is 6 gauge sufficient for the ground? If it must be within 5 feet of the supply entrance then we're looking at a run of about 35-40 feet. Also, is there a special clamp to attach the wiring to the plumbing? Thanks
 
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Old 07-20-05, 04:09 PM
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Originally Posted by sx460
Also, is there a special clamp to attach the wiring to the plumbing? Thanks
Yes, they're usually located near the conduit fittings at the hardware/home center. The clamps wrap around the pipe and have a screw-down lug for attaching the bonding wire. You may need to install a bonding jumper across the water heater pipes and to the steel natural gas lines if you have them also. You would need to install a bonding jumper across your water meter if your water supply line was metal.
 
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Old 07-20-05, 05:16 PM
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I just feel the need to clarify a bit.

If the house has a metallic pipe, in contact with the earth for at least 10', bringing the water in, it MUST be used as the primary grounding electrode. In this case ONLY the ground wire MUST be attached within 5' of where the water pipe enters the house. This ground also serves as the water piping bond.
Also, a ground rod (or two) are required as supplemental electrodes.

The OP has stated he has plastic feeding the house. In this case a water bond wire must be connected to the cold water pipe at any accessible place. Jumping to the hot is normally not necessary since many items in the system DO provide adequate continuity, such as shower and faucet mixing valves and water heaters.
You DO have to jumper around meters, plastic filter housings, etc. Anything removable or anything that breaks the metallic continuity of the piping system.

Most areas DO NOT want natural gas piping bonded to the house electrical system. These pipes are inherently grounded through the branch circuits that feed gas burning appliances.

I am not sure what racraft means by a two means of grounding the panel. If there is no metal water pipe entering the house all that's needed is a ground rod (or two) outside. Possibly he means two ground rods.
 
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Old 07-20-05, 10:18 PM
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Originally Posted by Speedy Petey
I just feel the need to clarify a bit.

If the house has a metallic pipe, in contact with the earth for at least 10', bringing the water in, it MUST be used as the primary grounding electrode. In this case ONLY the ground wire MUST be attached within 5' of where the water pipe enters the house. This ground also serves as the water piping bond.
Also, a ground rod (or two) are required as supplemental electrodes.

The OP has stated he has plastic feeding the house. In this case a water bond wire must be connected to the cold water pipe at any accessible place. Jumping to the hot is normally not necessary since many items in the system DO provide adequate continuity, such as shower and faucet mixing valves and water heaters.
You DO have to jumper around meters, plastic filter housings, etc. Anything removable or anything that breaks the metallic continuity of the piping system.

Most areas DO NOT want natural gas piping bonded to the house electrical system. These pipes are inherently grounded through the branch circuits that feed gas burning appliances.

I am not sure what racraft means by a two means of grounding the panel. If there is no metal water pipe entering the house all that's needed is a ground rod (or two) outside. Possibly he means two ground rods.

Thank you for the clarification. That makes sense regarding the grounding to the plumbing. We're not living there yet (will begin moving in this weekend), so it's good to get the the plumbing grounded now before we begin taking lots of showers. Thanks for all the great info!
 
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