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Posted By: beach Grounding to water pipe - 02/14/02 03:31 AM
A licensed electrical contractor I work with says running a ground wire from a recpt to a water pipe bonding with a copper strap is an approved method for obtaining a ground from a 2 wire system. Example: knob and tube wiring, he ran a #12 wire from the recpt to a water pipe (3/4 galv) to acheive a ground. I argued with him since it was my belief this was not an approved method.

Please shed some light please. I have a 2002 NEC. Please reference some code so I can better understand, also a suggested approved method if his is not.

The local is Sacramento, CA In city limits.

Thank you
Jon
Posted By: resqcapt19 Re: Grounding to water pipe - 02/14/02 03:39 AM
Jon,
Look at 250.130(C)
Don(rescqpt19)
Posted By: beach Re: Grounding to water pipe - 02/14/02 04:03 AM
In reading it is my understanding that his connection is only permitted if within 5 ft of the pipe entrance since it is not a commercial or indusrtial but rather a residential building.

IS THIS CORRECT?

Jon
Posted By: sparky Re: Grounding to water pipe - 02/14/02 10:37 AM
beach,
first you must consider if said conductor is a 'Bond" or a 'Grounding Electrode Conductor' (or GEC). The 5' rule would apply to the latter.
Posted By: Electricmanscott Re: Grounding to water pipe - 02/14/02 12:34 PM
Jon, I believe you are correct, you must run the ground to within 5 feet of water line point of entry, or you could run it into the panels ground bar. This or may not be accepted where you are. Here in Mass we are not allowed to do this. They have deleted 250.130(C)
Posted By: dana1028 Re: Grounding to water pipe - 02/14/02 10:45 PM
Beach - you are in Calif. - the NEC 1996 is the state adopted code (not '99 or 2002) -...so

250-50(b)Excetion - says "shall be permitted to be grounded to any accessible point on the GES as described in 250-81, or to any accessible point on the GEC."...going to 250-81....
250-81(a) - Metal underground water pipe - there is no requirement for attaching within 5' of entry into the bldg....(unless I missed somthing but I don't think I did) ....so - your elect. contractor wired this correctly....until Calif. finally gets around to adopting the 1999.
Posted By: Electricmanscott Re: Grounding to water pipe - 02/14/02 11:44 PM
Wow I can not beleive there are states out there that do not keep up with current code. Anyone still using the knob and tube out there?
Posted By: beach Re: Grounding to water pipe - 02/15/02 05:27 AM
Knob and tube? Of course....Why? Have you heard of something better?
Posted By: dlabrenz Re: Grounding to water pipe - 02/15/02 05:39 AM
The 5 foot rule for the water pipe connection first appeared in the 1993 NEC. If the grounding connection was not made within the first five feet from the point where the water service enters the building, it would not appear to be done correctly.
Posted By: Redsy Re: Grounding to water pipe - 02/15/02 01:09 PM
Knob and tube is still an acceptable wiring method as an extension to existing k&t.
Not that I would choose to do so.
Posted By: dana1028 Re: Grounding to water pipe - 02/15/02 05:32 PM
Beach - dlabrenz is right...I'm so used to using the '99 and '02 I just couldn't find the right section in the old '96 for Calif...:O "interior metal water pipe located more than 5' from the point of entrance of the bldg. shall not be used as a part of the GES OR as a conductor to interconnect...." - sorry
Posted By: Tom Baker Re: Grounding to water pipe - 02/16/02 12:22 AM
The easy solution is to install a GFCI. It does not have to be bonded. The ground, if used does not have to be within 5 of the entrance of the water pipe into the building.

The five foot rule applies when you are using the water pipe as a grounding electrode. Bonding of the recptacle ground is a different rule. See 250.130(C) and 406.#(D).

One disadvantage of using a GFCI on a non grounded circuit is for some applications a ground is required, such as a TVSS. But using a GFCI is better than having the ground prong cut off a male cord cap.
Posted By: resqcapt19 Re: Grounding to water pipe - 02/16/02 03:39 AM
Tom,
I don't find any permision in 250.30(C) to use a water pipe for the ground connection to a replacement receptacle. If you install an EGC to the receptacle it must be installed per Article 250.
Don(resqcapt19)
Posted By: Electricmanscott Re: Grounding to water pipe - 02/16/02 01:06 PM
Loooking in 99 book 250.130(c) " Any accesible point on the grounding electrode system as described in 250-50" There is a note in the handbook stating that an interior metal water pipe more than five feet from entrance is no longer allowed due to the use of plastic piping and fitings. I went to a service call where the person was belted when he got into the shower. Turns out a kitchen receptacle was grounded to a cast iron sewer pipe that went to a septic system. Not a good ground I guess. The receptacle somehow was fried and the cast iron pipe became live. Turn on the shower, water going down the drain, feet in water, grab the faucet, ZAP! He was ok, and his kids were next in line to take a bath. Fortunately he went first. Also the drain on the sink was so hot that the water in the trap was actually boiling and making steam. I havent seen anything like it before or since.
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