Ground rods first..

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Old 03-14-14, 02:03 AM
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Ground rods first..

I have 100amp service in my house, is it ok to run the ground to the ground rod first and then to the water pipe? Reason being is that the water pipe is about 15' away from the disconnect switch and I have ample space for 1 or even 2 ground rods. Also, I want to use bare #6 solid in rigid conduit (some areas conduit may be buried) to run the ground, is this OK or does it need to be insulated wire?

All help greatly appreciated.
 
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Old 03-14-14, 02:41 AM
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The order does not matter, but it must be one continuous piece. Bare or insulated is fine.

If metallic conduit is used you will need to bond both ends. I would use PVC or nothing. This can even be buried without a conduit. Keep it against the foundation to avoid shovel damage.
 
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Old 03-14-14, 03:04 AM
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I am not understanding, bond the conduit that will be used as protection?
 
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Old 03-14-14, 07:39 AM
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If metallic conduit is used, both ends of the conduit needs to be physically connected to a ground wire. Either either the ground in the pipe, or another ground wire that is connected to the same place as the wire in the pipe. Using PVC conduit will avoid having to do this.

If the metal conduit is connected to the panel steel it is effectively bonded on that end. The other end will still need to be bonded.
 
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Old 03-14-14, 08:42 AM
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Suggested start: Run a grounding electrode conductor of the largest size* required for any of the grounding electrodes non-stop from the system neutral (panel neutral) to that grounding electrode. It may daisy chain from there to other grounding electrodes or additional conductors as GEC may be run from other grounding electrodes and/or be clamped/spliced/tapped so as to bond all of the grounding electrodes. The entire path from each electrode to the system neutral needs to be of at least the minimum required size for that electrode.

* See NEC table 250.66. For a 100 amp service the minimum size of GEC to the cold water pipe is #6 copper; for any service the maximum required GEC to a ground rod is (also) #6 copper.
 

Last edited by AllanJ; 03-14-14 at 09:07 AM.
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Old 03-14-14, 11:18 AM
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If metallic conduit is used you will need to bond both ends.
This is why in residential installations I recommend running the GEC open without conduit and securing with copper plated 1-hole straps. The residential installations I see with the GEC in metallic conduit are usually not properly bonded.
 
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Old 03-14-14, 12:43 PM
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This is why in residential installations I recommend running the GEC open without conduit and securing with copper plated 1-hole straps. The residential installations I see with the GEC in metallic conduit are usually not properly bonded.

I was thinking using a copper 1-hole strap connecting the #4 or #6 solid and bare wire to the ridgid 2" conduit on the service disconnect that goes into the ground.
From there I can dig a few inches and bury the solid and bare ground wire to where it will connect to the ground rod.
From there I can bury it again and take it to where the water pipe comes in from the street.
Does this sound OK?

Also, should I be using solid or stranded, bare or insulated?

Thanks to all for helping.
 

Last edited by zizanio; 03-14-14 at 01:13 PM.
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Old 03-14-14, 04:17 PM
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I believe you misunderstand to primary purpose of a ground wire to the water pipe. Its purpose is human safety - to connect a ground bus bar in the main disconnect box to water pipes. So that pipes and all safety grounds inside the building remain at same potential. So that a current fault to any pipe causes the appropriate circuit breaker to disconnect.

House inspectors will also want to inspect this connection. Since inspection is the only way to confirm this essential safety ground connection exists. Best is to route a separate ground wire from the disconnect (breaker) box to within feet of where a water pipe enters the building.

Desireable is to have one ground from that bus bar to a common earthing electrode. And another from that same bus bar to a cold water pipe. Then any one fault does not create numerous other problems.

As I read it, your buried connection from main breaker box to cold water pipe cannot be verified by inspection. It may be acceptable to a code inspector. But its purpose implies it must be visually inspected to confirm it exists and has not been compromised.

Use solid. Stranded wire fails faster ans is not acceptable in many venues. Buried wire should be at least 18" deep to protect from damage and other reasons.
 
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Old 03-14-14, 06:59 PM
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I was thinking using a copper 1-hole strap connecting the #4 or #6 solid and bare wire to the ridgid 2" conduit on the service disconnect that goes into the ground.
Not quite sure what you mean. A 1-hole strap generally is used to secure the GEC to the face of the wall or foundation down to the ground rod.
 
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Old 03-14-14, 09:17 PM
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This is how you would bond the end of the metallic conduit.

 
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