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andrewc24301
Jan 23, 2009, 10:48 PM
Is it nessesary to bond ground to a water pipe?

After becoming active in this board in particular, the thought occurs to me that perhaps the water pipe is to be bonded to the ground in the service panel?

If this is the case, then what do you do when your pipes are plastic?

Everything is plastic, except for the brass valves, and a small section of copper (about 2' long) by the shut off valve for the house. The line from the meter to the house is blue plastic pipe, then that 2' of copper, then the rest is CPVC.

Mine is not, it used to be, until I had the pipes redone to PVC. It still has the ground rod, but that's it.

stanfortyman
Jan 24, 2009, 06:08 AM
Metallic water piping systems MUST be bonded. A few sections of several feet is not a "system" of piping.
250.104(A)


At the same time, if your piping entering the house is metallic, and in contact with the earth for 10' or more, it MUST be used as an electrode.
250.52(A)(1)


Here is what it says in the 2008 NEC handbook. This is note the code, it is the commentary:

Bonding the metal water piping system of a building or structure is not the same as using the metal water piping system as a grounding electrode. Bonding to the grounding electrode system places the bonded components at the same voltage level. For example, a current of 2000 amperes across 25 ft of 6 AWG copper conductor produces a voltage differential of approximately 26 volts. Sections 250.104(A)(1) and (A)(3) require the metal water piping system of a building or structure to be bonded to the service equipment or grounding electrode conductor or, where supplied by a feeder or branch circuit, to the building or structure disconnecting means or grounding electrode conductor. Information concerning bonding provisions for buildings with multiple occupancies and isolated metal water piping systems is contained in the commentary for 250.104(A)(2).
Where it cannot be reasonably concluded that the hot and cold water pipes are reliably bonded through mechanical connections, an electrical bonding jumper is required to ensure that this connection is made. Some judgment must be exercised for each installation. Isolated sections of metal piping (such as may be used for plumbing fixture connection) that are connected to an overall nonmetallic water piping system are not subject to the requirements of 250.104(A). The isolated sections are not a metal water piping system. The special installation requirements provided in 250.64(A), (B), and (E) also apply to the water piping bonding jumper.
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andrewc24301
Jan 24, 2009, 08:29 AM
So from all this I gather that since I don't have a metallic piping system then it doesn't have to be grounded?

stanfortyman
Jan 24, 2009, 08:32 AM
You can't bond/ground plastic. :D

donf
Jan 24, 2009, 10:23 AM
Of course you can! Of course it would be meaningless but if you wanted you could. (Yuk, Yuk)