GEC
- Thread starter Djelite
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
A single ground rod is only considered a grounding electrode when it has been tested to prove 25Ω or less. If you are not testing the single rod then two rods are required.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Isn't the pipe only to be supplemented by one rod?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
No it needs to be supplemented by another electrode. A single rod unless tested and proven to be 25 ohms or less is not an electrode.
250.53(2) Exception
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
That's not the way I'm reading it. It says if the pipe, rod, or plate meets the 25 ohm, then no additional electrode needed. So if the pipe didn't meet it, then a rod added would satisfy that. It doesn't say a single rod is not an electrode.
One pipe + one rod = satisfied
(2) Supplemental Electrode Required. A single rod, pipe, or
plate electrode shall be supplemented by an additional electrode
of a type specified in 250.52(A)(2) through (A)(8). The
supplemental electrode shall be permitted to be bonded to one
of the following:
(1) Rod, pipe, or plate electrode
(2) Grounding electrode conductor
(3) Grounded service-entrance conductor
(4) Nonflexible grounded service raceway
(5) Any grounded service enclosure
Exception: If a single rod, pipe, or plate grounding electrode has a
resistance to earth of 25 ohms or less, the supplemental electrode shall
not be required.
250.53(D)(2) states:
If the supplemental electrode is of the rod, pipe, or plate type, it shall comply with 250.53(A).
which, when you look at 250.53(A), to me, indicates you need the two rods unless you meet the 25 ohm rule.
If the supplemental electrode is of the rod, pipe, or plate type, it shall comply with 250.53(A).
which, when you look at 250.53(A), to me, indicates you need the two rods unless you meet the 25 ohm rule.
I think you’re right
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Sorry about that I gave the wrong code reference but the answer is the same being the bold is incorrect unless the single rod is tested. Augie gave the correct code reference.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
You're supplementing the pipe because a single pipe, if not tested, doesn't meet the 25 ohm. The rod is the supplement. It would be the same way if it was a rod and needed supplementing, the pipe would satisfy that.
250.53(A) is what I posted above. It (the exception) says if you only have a single rod, pipe, or plate and it does meet the 25 ohm, then no supplement electrode needed. And since the pipe was not tested it does need a supplement and the rod would be that.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Note the water pipe doesn't have an allowance for checking that the resistance to ground is 25 ohms or less. The water pipe always needs a supplemental electrode. 250.53(D)(2).
250.53(A)(2) specifies that the supplement to a ground rod be an electrode "of a type specified in 250.52(A)(2) through (A)(8)". That means that a water pipe, which is the type in 250.52(A)(1), may not be the supplemental electrode to a ground rod.
The upshot is that you need the water pipe and two ground rods, unless you confirm that one ground rod is 25 ohms or less to remote earth.
Cheers, Wayne
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
- Occupation
- Licensed Electrician
You are confusing water pipe with a piece of grc used for an electrode piece of pipe.
No im not
In nyc we have to go full size to to the water piping system. The water piping system in the ground is your grounding electrode it needs to be supplemented so we use a rod that rod get a #6 gec. I wasn’t sure if you needed one or two but Augie was correct inhis info and code reference. I also found it in earlier codes which refers you to 250.53 and like Infinity stated it must be one rod tested for 25 ohms or less or two rods