Ground rod placement


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Old 01-11-04, 02:25 PM
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Question Ground rod placement

Installing new 200amp interior main breaker panel. At present ground is to water pipes only (From the soon to be replaced 100amp panel). The house is cement block and the exterior has a 3' wide poured block walkway on all sides.
Can I drive a ground rod on the interior of the house? The house cleanout trap is very near the panel and there is plenty of exposed earth. Or, do I have to drill a hole in the cement block wall, drill into the walkway and bury the ground wire and cement over top of the rod?
Thanks in advance.
 
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Old 01-11-04, 02:33 PM
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There is nothing in the code that states the rod must be installed outdoors. It says the end must be at or below grade. This can be the basemant floor.

Are you OK on ALL the other requirements for replacing a service?
 
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Old 01-11-04, 02:50 PM
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Thanks for the "speedy"reply. I think I'm OK with other code concerns. What I am doing in the interim is running a new service entrance cable (100amp rated) from the meter socket into the 200amp panel BUT by passing the Main Switch and wiring into a 100amp Double pole breaker which will act as my Main Disconnect. Any concerned comment on this approach is also appreciated.
 
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Old 01-11-04, 05:47 PM
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Is this so you can change the panel now and do the rest of the service later? Or do you intend to keep it this way? You did say interim.

Sounds OK as long as you'll replace the meter socket, riser & SE cable soon.
 
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Old 01-11-04, 06:58 PM
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Yes, this is a short term connection. Eventually the drop, socket, etc will be replaced to accept the 200. Another question I have regarding the ground rod was that I have read in various places that 200amp requires 2 ground rods. Is this correct? If so, are they in a continuous run or does that mean 2 different solid copper lines originating in the panel going to 2 different rods? The house is built on sand kept damp by sea water. I've been told this is a very good ground conductor situation and would meet requirements with only one.
Thanks again.
 
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Old 01-11-04, 07:48 PM
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stephen

That 100A double pole breaker will need an accessory kit to fasten it in place.

Regarding 2 ground rods regardless of the size of the service: If you can't prove that the first rod has 25 ohms or less resistance then a second rod is required no closer than 6 feet to the first. The cost of the meter to prove less than 25 ohms makes it much easier to just drive the second rod. I find it easiest to run your grounding electrode conductor to the first rod, double it over under the clamp at the first rod and continue it on to the second.
 
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Old 01-11-04, 08:13 PM
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All I can say is if you don't need at least a 3# lump hammer to drive the rod in you probably need another rod. If it takes some effort one is fine.
I have never seen an inspector ohm out a ground rod.
Your local code may require a second rod regardless of the ohms. Better check on that.
 
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Old 01-11-04, 08:22 PM
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"100A double pole breaker will need an accessory kit to fasten it in place"
I'm assuming that means it needs to be locked down somehow? or a kit to put it in the position of the 200A Main Breaker? I was going to put it (The 100A Double) in the nearest available breaker spot near the top of the panel and not use the 200A disconnect at all - leaving it in place, OFF postion, tape it down. Again, this is only a short term thing and no one but me has access to the panel.
I really appreciate the dialogue here.
 
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Old 01-12-04, 08:14 AM
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Originally posted by stephen001
"100A double pole breaker will need an accessory kit to fasten it in place"
I'm assuming that means it needs to be locked down somehow? or a kit to put it in the position of the 200A Main Breaker? I was going to put it (The 100A Double) in the nearest available breaker spot near the top of the panel and not use the 200A disconnect at all - leaving it in place, OFF postion, tape it down. Again, this is only a short term thing and no one but me has access to the panel.
I really appreciate the dialogue here.
The kit is to lock it down in it's installed slot not to change out the factory installed main breaker. If by any chance your panel is SquareD use the 2/4 position for your temporary back fed main breaker. You can then add the interlock kit to turn that breaker together with the factory installed main into a generator transfer switch to supply power to your home from a portable generator. Regardless of the brand of the panel buy your lock down kit before you cut your temporary meter tail. The lock down kits are only intended to install in certain positions.
--
Tom H
 
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Old 01-12-04, 02:12 PM
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Originally posted by Speedy Petey
If it takes some effort one is fine.
That's not a very scientific approach. Granted, it may prove to be true in some or even many cases, but I would hardly think it applies to all.


Originally posted by Speedy Petey
I have never seen an inspector ohm out a ground rod.
Neither have I Speedy, but since it is a code requirement, wouldn't we have to prove it to them?
 
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Old 01-12-04, 02:48 PM
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Tom,

The Square D backfeed clip is only for the smaller loadcenters. The largest one that will accept it I believe is the 8/16 ckt one.
 
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Old 01-12-04, 04:44 PM
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Bolted, I am not one to cut corners with regard to the code but in my area ground rods can be so hard to install I have no question that they are making good contact.
If this were a real issue don't you think they would just make it code to sink two? Regardless of the ohms.

I don't feel it is something we have to prove. Do you go around saying; "This 22cu/in box has a fill of only 18cu/in" or "I have only 9-#12 wires in this 3/4" conduit"?
Have you yourself EVER ohm'd out a ground rod? In my over 15 years experience I can honestly say I don't even know how to check one.
 
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Old 01-12-04, 05:56 PM
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Bolted, check out this ongoing thread on Mike Holt's forum:

http://www.mikeholt.com/codeforum/ul...c;f=7;t=000617
 
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Old 01-12-04, 07:26 PM
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Pete,
250.56 requires that the installer prove to the inspector that he has 25 ohms or less. In most cases it is easier and cheaper to just install the second rod. The effort it takes to install the rod has nothing to do with the soil conductivity. The soil conductivity determines the resistance.
Don
 
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Old 01-12-04, 08:34 PM
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Well gentlemen, I didn't think this thread would get so long. Anyway, I hope to get to the work tomorrow. I installed one ground rod today to see the effort. I pushed it down 7' by hand (no kidding) than hit it with a chunk of 4x4 for the last 1'. Didn't think it would be that easy.

How do I go about checking the resistance?
Is it code in NY to have 2 rods for (near future) 200A service?
Should I reconnect the old water pipe ground wire too?
 
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Old 01-13-04, 03:44 AM
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resqcapt19,
I'm quite aware of 250.56. But no where does it state we have to prove the resistance. Like I said above, we don't go around with the inspector stating box fill, etc.
I am not trying to short the code but this is something that has NEVER come up in my experience.
Check the link provided, many other qualified electricians agree that this is not as big a deal as it is made out to be. If it were it would be code.

Stephen- Be careful. Many different codes in NY. Some require two rods, some require #4 to the rods, some only #6, some require a license. Better check before you do any work.
 
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Old 01-13-04, 04:16 PM
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Pete,
If you can't prove it to the inspector he has every right to require a second rod. Many inspectors take that approach. As far as box fill I know inspectors who open random boxes and make a conductor count to check box fill.
Don
 
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Old 01-13-04, 04:20 PM
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Stephen,

If your pipes are metal then they MUST be connected to the electrical system ground.
 
 

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