5ft rule

[LarryFine]

250.56 does not require a 2nd ground rod, if the waterline IS an electrode.

Agreed, and if an inspector challenges me to prove an existing water-pipe is electrically continuous, I look him right in the eyes and say, "I'll be driving a second rod."

Actually, I do use two rods routinely, except for one remodeled commercial job where a new 1.5" copper water line was installed, and I made sure the inspector saw it.

The single existing rod was inside the basement-located electrical room, with an old thick concrete floor poured around it, and I didn't feel like boring a hole through it.

 

[don_resqcapt19]

The rod(s), used as a supplemental grounding electrode, for a metal underground water pipe must meet the requirements of 250.56. The only reason that the code requires the supplemental electrode for the water pipe is because it is likely that the water pipe may be repaired or replaced using nonmetallic pipe or fittings. When this happens the rods are no longer supplemental electrodes, they are now the service grounding electrodes. They must be fully qualified to serve as such when they are installed and that requires compliance with 250.56.

 

[jxofaltrds]

Are you saying that a single rod can qualify as a supplemental electrode even if it doesn't meet the 25 ohms or less rule?

Rob

Yes I am saying that IF it is not the only electrode.

 

[infinity]

Rob

Yes I am saying that IF it is not the only electrode.

I can see how you're interpreting that. You saying that if your single rod has a resistance above 25 ohms your water pipe would qualify as the "one additional electrode" required by 250.56.

The real question is as written does 250.53(D)(2) allow you to use the water pipe as you've stated. Most people would say no due to the reason that Don mentioned, but the wording is rather ambiguous.

 

[jxofaltrds]

I can see how you're interpreting that. You saying that if your single rod has a resistance above 25 ohms your water pipe would qualify as the "one additional electrode" required by 250.56.

The real question is as written does 250.53(D)(2) allow you to use the water pipe as you've stated. Most people would say no due to the reason that Don mentioned, but the wording is rather ambiguous.

Rob

You and Don are correct. If you read the commentary in 250.53(D)(2).

I agree with the commentary. But many say that it is in unenforcable.

Do we rely on the words in the code only or should we use the commentary to enforce the code?

In Ohio the code must be liberally interpreted. So if an electrical contractor has a good arguement as in my above example should he pass? Or should we use the commentary to show that the arguement is flawed?

I say use the commentary. I was just trying to make a point that when something is unclear that we use the commentary and both of you showed that my arguement is flawed.

I think that as a group we should agree that the commentary be 'used'.

Any takers????

 

[jumper]

Rob



I agree with the commentary. But many say that it is in unenforcable.

It is not enforcable in VA

Do we rely on the words in the code only Yes or should we use the commentary to enforce the code? No

In Ohio the code must be liberally interpreted. So if an electrical contractor has a good arguement as in my above example should he pass? Or should we use the commentary to show that the arguement is flawed?

You can use it to help get your point across, but you cannot enforce it.

I say use the commentary

I think that as a group we should agree that the commentary be 'used'.

Not me.

Any takers????

Nowhere in my state code does it say that I have to follow NECH commentary or FPNs.

 

[infinity]

But back to Mike's original arguement. Can the water pipe be considered the "one additional electrode" that is required when the rod exceeds 25 ohms?

 

[jxofaltrds]

But back to Mike's original arguement. Can the water pipe be considered the "one additional electrode" that is required when the rod exceeds 25 ohms?

If you read the code then maybe.

If you read the commentary then no.

 

[raider1]

But back to Mike's original arguement. Can the water pipe be considered the "one additional electrode" that is required when the rod exceeds 25 ohms?

Using the 2008 NEC no because the new language in 250.56 only allows the additional electrode to be one of the types listed in 250.52(A)(4) through (A)(8). A water pipe is listed in 250.52(A)(1).

250.56 Resistance of Rod, Pipe, and Plate Electrodes.
A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(4) through (A)(8). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart.

Chris

 

[infinity]

Using the 2008 NEC no because the new language in 250.56 only allows the additional electrode to be one of the types listed in 250.52(A)(4) through (A)(8). A water pipe is listed in 250.52(A)(1).
Chris

I knew that there had to be a simple answer. I misread the part about electrodes (4)-(8) which as Chris stated would exclude the water pipe.

 

[jxofaltrds]

Then if I have a CCEE (250.52(A)(3)) and a waterline (250.52(A)(1)) I still need to add a supplemental (250.53(D)(2)) and possibly an auxilliary (250.56 & 250.54).

Correct? Or do some of you stop with just the CCEE and the waterline?

 

[infinity]

Then if I have a CEE (250.52(A)(3)) and a waterline (250.52(A)(1)) I still need to add a supplemental (250.53(D)(2)) and possibly an auxilliary (250.56 & 250.54).

Correct? Or do some of you stop with just the CEE and the waterline?

You never need an auxiliary since it's only a design option. The water pipe need to be supplemented by one of the electrodes 250.52(A)(2) through (A)(8). The CEE is one of those at #(3) so when using the CEE, you only need the CEE and the water pipe, nothing more.

 

[jxofaltrds]

You never need an auxiliary since it's only a design option. The water pipe need to be supplemented by one of the electrodes 250.52(A)(2) through (A)(8). The CEE is one of those at #(3) so when using the CEE, you only need the CEE and the water pipe, nothing more.

I should have re-read 250.53(D)(2).

 

[Smart $]

FWIW, the wording of 250.53 is likely to change in the 2011 cycle.

The following is the pertinent parts of the ROP Draft stage rewrite:

250.53 Grounding Electrode System Installation.
(A) Rod, Pipe, and Plate Electrodes. Rod, pipe and plate
electrodes shall meet the requirements of (A)(1) through
(A)(3).
?
(2) Supplemental Electrode Required. A 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) The rod, pipe or plate electrode
(2) The grounding electrode conductor
(3) The grounded service-entrance conductor
(4) The 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.
?
?
(D) Metal UndergroundWater Pipe. If used as a grounding
electrode, metal underground water pipe shall meet the
requirements of 250.53(D)(1) and (D)(2).
?
(2) Supplemental Electrode Required. A metal underground
water pipe shall be supplemented by an additional
electrode of a type specified in 250.52(A)(2) through
(A)(8). If the supplemental electrode is of the rod, pipe, or
plate type, it shall comply with 250.56. The supplemental
electrode shall be bonded to one of the following:
(1) The grounding electrode conductor
(2) The grounded service-entrance conductor
(3) A nonflexible grounded service raceway
(4) Any grounded service enclosure
(5) As provided by 250.32(B)
Exception: The supplemental electrode shall be permitted
to be bonded to the interior metal water piping at any
convenient point as covered in 250.68(C)(1), Exception.

However, 250.56 shows no change.