Residential Cold Water Bond At Point Of Entry

[Ravenvalor]

Can anyone speculate why the code was changed several years ago that requires the cold water line to be bonded to the service within 5' of where the metal water line enters the home?

Thank you for your thoughts.

 

[infinity]

You mean connection when the water pipe is a grounding electrode not bonding the pipe?

I think that it's probably just a practical thing. The old NEC wording said to land the GEC on the street side of the water main which may have been problematic if it was placed right at the wall. That was removed in the 1971 NEC. Also with the required bonding jumper around the water meter it doesn't really matter what's between the entry point and the 5' mark.

 

[ptonsparky]

Ease of inspection would be a plus, but doubtful that came into play.

 

[kwired]

Can anyone speculate why the code was changed several years ago that requires the cold water line to be bonded to the service within 5' of where the metal water line enters the home?

Thank you for your thoughts.

This 5 foot from entrance change was back in about 1990, 1993 maybe 1996 at latest. It only applies to connection to a water pipe grounding electrode. If you have interior metal water piping system but with no qualifying grounding electrode as the supply, you can bond that interior piping anywhere that you want, per NEC wording. some localities still may have a place they desire to see it bonded - often at the water heater or maybe still near the entry of the water piping.

 

[LarryFine]

Can anyone speculate why the code was changed several years ago that requires the cold water line to be bonded to the service within 5' of where the metal water line enters the home?

I'm great at speculating.

I believe it's so there is little question that the connection to the exterior piping is maintained over time.

 

[kwired]

I'm great at speculating.

I believe it's so there is little question that the connection to the exterior piping is maintained over time.

I didn't read OP carefully enough - I agree though, the chance of interior piping not being maintained as a conductive pathway is not as great anymore as it once was and therefore you risk losing continuity to the electrode portion if you don't bring the bonding to a point very close to the electrode.

 

[LarryFine]

. . . the chance of interior piping not being maintained as a conductive pathway is not as great anymore as it once was . . .

Do you mean the opposite, that the chance of the pathway being maintained is not as great, since the use of non-metallic plumbing is more widespread than in the olden days?

 

[tortuga]

The change happened in the 1993 code, prior to 1993 the entire metal piping system was considered fair game as a grounding electrode (bonding) conductor. For example prior to 1993 ungrounded outlets could be made grounded by taking a single EGC to the nearest water pipe [see 250-50 Exception 1990 NEC] also telephone and cable installers could use the metal water pipe as a grounding electrode conductor of unlimited length. [800-40(b)(1) 1990 NEC]. That of course can cause all kinds of problems, so the code was changed.

 

[tom baker]

The change was made to ensure the connection to the water pipe GE was not in the middle of the dwelling unit, where a section of NM pipe would isolate the connection pipe from the GE going outside

 

[Ravenvalor]

This all makes good sense. Maybe the insurance industry did studies showing how effective the change was in reducing house fires and electrical shocks.

Thanks for the great answers. Upgrading a service this week where the home built in 1952 still had 99% of its original galvanized pipe and still had a metal supply pipe feeding the home from the road. The only non-metallic pipes were 2 - approximately 3' pieces going to hot and cold on the hot water heater.

 

[kwired]

Do you mean the opposite, that the chance of the pathway being maintained is not as great, since the use of non-metallic plumbing is more widespread than in the olden days?

I think we both said same thing, need to look carefully at wording or you can maybe interpret wrong.

But yes possible repair or replacement of piping components with non conductive components will potentially interrupt the path to the electrode is what change back in the 90's was mostly about.

 

[tortuga]

Upgrading a service this week where the home built in 1952 still had 99% of its original galvanized pipe and still had a metal supply pipe feeding the home from the road. The only non-metallic pipes were 2 - approximately 3' pieces going to hot and cold on the hot water heater.

Yeah service upgrades that's where it gets tricky for me. Had a plumber friend call up he was re-piping a house with pex, a old 1900's Victorian. He said there were a few ground clamps he did not know what to do with, I figured it was the water bond told him it would take no more than a hour two to fix.
I get over with some ground rods and a roll of bare and to my surprise there are no less than 10 water pipe clamps dangling all over the basement, sent the apprentice into the crawl space and found several more. Turns out somebody in the past grounded every outlet in the first floor of the house to the water pipes and they had two on gas pipes.

 

[ptonsparky]

Yeah service upgrades that's where it gets tricky for me. Had a plumber friend call up he was re-piping a house with pex, a old 1900's Victorian. He said there were a few ground clamps he did not know what to do with, I figured it was the water bond told him it would take no more than a hour two to fix.
I get over with some ground rods and a roll of bare and to my surprise there are no less than 10 water pipe clamps dangling all over the basement, sent the apprentice into the crawl space and found several more. Turns out somebody in the past grounded every outlet in the first floor of the house to the water pipes and they had two on gas pipes.

Other than the gas lines, that is the way it was done, if they weren't clipped off.