bonding

[John Evorik]

We have a200a 1/0 house service. we installed a ground rod and water bond copper coming in from water co. Inspector says 100a ser. 1 grd rod 200a 2 grd rods. we are still on the 2008 code book. were is he coming from? just john

 

[LEO2854]

We have a200a 1/0 house service. we installed a ground rod and water bond copper coming in from water co. Inspector says 100a ser. 1 grd rod 200a 2 grd rods. we are still on the 2008 code book. were is he coming from? just john

Read 250.53.

 

[roger]

If rods are used the number will be the same for any size service, see Leo's NEC article section.


Roger

 

[infinity]

The inspector is 1/2 right and 1/2 wrong. As mentioned the size of the service is irrelevant to the number of rods required.

 

[cowboyjwc]

It's in the 2011 that you need two, but many jurisdictions were asking for that years ago, so it could be a local amendment. Just be glad you didn't put in a 1600 amp service.:roll:

 

[Smart $]

It's in the 2011 that you need two, but many jurisdictions were asking for that years ago, so it could be a local amendment. Just be glad you didn't put in a 1600 amp service.:roll:

It was in 2008, too. Just written differently...

250.53 said metal underground water pipe must have supplemental electrode.... drive and connect rod... 250.56 says if single rod doesn't have 25 ohms or less, must be augmented by another electrode (not water pipe)... drive and connect second rod.

 

[cowboyjwc]

It was in 2008, too. Just written differently...

250.53 said metal underground water pipe must have supplemental electrode.... drive and connect rod... 250.56 says if single rod doesn't have 25 ohms or less, must be augmented by another electrode (not water pipe)... drive and connect second rod.

Yes, but now it says that if a ground rod is used it must be augmented with another ground rod.

 

[electricguy61]

BTW: According to 310.15(B)(6) (2008NEC) 1/0 is too small. Should be 2/0 for 200amp service

 

[Smart $]

Yes, but now it says that if a ground rod is used it must be augmented with another ground rod.

One says potato. The other says pot?to. :roll:

 

[mwm1752]

Yes, but now it says that if a ground rod is used it must be augmented with another ground rod.

there are more than one way to supplement a single rod install --- The OP did state the water line was bonded so I would assume it was not used as an electrode.


Cowboy are you saying if the water pipe is used as an electrode & supplemented by a rod -- second rod is required?

 

[infinity]

there are more than one way to supplement a single rod install --- The OP did state the water line was bonded so I would assume it was not used as an electrode.


Cowboy are you saying if the water pipe is used as an electrode & supplemented by a rod -- second rod is required?

You need two rods to make a rod electrode unless you can prove that a single rod is 25 ohms or less.

 

[mwm1752]

You need two rods to make a rod electrode unless you can prove that a single rod is 25 ohms or less.

that wasn't the question --- You don't need 2 rods when your electrode system consist of water pipe & a single supplemental rod.

 

[Smart $]

that wasn't the question --- You don't need 2 rods when your electrode system consist of water pipe & a single supplemental rod.

But that is the question, so to speak...

While one electrode (1st rod) is required to supplement the water pipe electrode, there isn't any provision relinquishing the requirement for a 2nd rod to supplement the 1st, where the resistance of the 1st is more than 25 ohms (or not tested).

 

[mwm1752]

l

 

[cowboyjwc]

But that is the question, so to speak...

While one electrode (1st rod) is required to supplement the water pipe electrode, there isn't any provision relinquishing the requirement for a 2nd rod to supplement the 1st, where the resistance of the 1st is more than 25 ohms (or not tested).

What he said. And I can bet that most of you don't have the equipment required to prove that the ground rod has 25 ohms or less of resistance.

 

[kwired]

A 15 amp service for a single circuit application still needs 2 ground rods unless you can prove the first rod has a resistance of 25 ohms or less.

The change in 2008 was primarily a change of wording but not really a change of intention of the rules. Before that changet the way it was worded you could just install one rod and if the inspector questioned it you could ask him to prove your single rod was more then 25 ohms, now the way it is worded you have to prove to the inspector that it is 25 ohms or less if you only want to install a single rod. Since most do not have equipment or know how to properly test the rod it is usually just simpler to install two rods and be done with it.

 

[cowboyjwc]

A 15 amp service for a single circuit application still needs 2 ground rods unless you can prove the first rod has a resistance of 25 ohms or less.

The change in 2008 was primarily a change of wording but not really a change of intention of the rules. Before that changet the way it was worded you could just install one rod and if the inspector questioned it you could ask him to prove your single rod was more then 25 ohms, now the way it is worded you have to prove to the inspector that it is 25 ohms or less if you only want to install a single rod. Since most do not have equipment or know how to properly test the rod it is usually just simpler to install two rods and be done with it.

Ok that's not....wait....what? I....um....I...I think we just agreed on something.:slaphead:

 

[infinity]

that wasn't the question --- You don't need 2 rods when your electrode system consist of water pipe & a single supplemental rod.

You still need two rods, my initial response was correct.

 

[GoldDigger]

It was in 2008, too. Just written differently...

250.53 said metal underground water pipe must have supplemental electrode.... drive and connect rod... 250.56 says if single rod doesn't have 25 ohms or less, must be augmented by another electrode (not water pipe)... drive and connect second rod.

Currently (2011 and 2014), there is no .56 and .53 says that if a rod electrode is used it must be supplemented by one of a list of types which specifically does not include an underground water pipe, but does include another rod.
Then it adds that if the single rod electrode has a resistance of 25 ohms or less, then no supplemental electrode is needed. That supplemental electrode may be, but does not have to be rod pipe or plate. If you have one of the other types listed in .52(A) (2)-(6), then you do not specifically need another ground rod even when the original rod has a resistance greater than 25 ohms.
It is just that making one of the other types is difficult enough that it has become standard practice to drive a second rod instead.