Thread: CSST bonding

Is there any convention or requirement as to where a plumber puts the bond? What I mean is; "within 25 feet of the cut off" or "where clearly visible and readily accessible?" Even when I’m lucky enough to stumble onto the connection at the gas line fitting, so far I am batting .000 for finding the connection at the grounding electrode.

http://permittingservices.montgomerycountymd.gov/permitting/pdf/csst.pdf

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Bonding the water supply is typically required near the main water shutoff. When the gas is bonded, I usually find it adjacent to the gas meter or the water heater (assuming a gas fired water heater). Many times the cold, hot and gas are bonded there.

I really only find gas bonded on newer homes. Hot water bonding is about the same. Quite often I am unable to visually verify.

The bonding conductor is sometimes connected directly to the ground rod or ufer. I usually see it (actually, I assume that it is one of the two #6 bare wires) in the service equipment panel.

I don't think a plumber can not do bonding unless he is licensed to do so. The bonding should be the electrcians job.

From the NEC. (bold and underlining are mine)
- 250.104 Bonding of Piping Systems and Exposed Structural Steel.
- - (B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.
- - - FPN: Bonding all piping and metal air ducts within the premises will provide additional safety.

That states *what*, which pretty much controls *where* (to some degree, they could, of course, run really long bond conductors).

I believe that a metal water supply line to has to be bonded within 5 feet when it enters the crawl/slab.

Originally Posted by James Duffin

I believe that a metal water supply line to has to be bonded within 5 feet when it enters the crawl/slab.

Yes, sort of ... within 5 feet of where the water pipe enters the structure, which could be in the crawl space or basement, but it also could be in a garage, in ...

I think it is the first five visible feet...

Originally Posted by James Duffin

I think it is the first five visible feet...

From the NEC. (bold is mine)
- 250.52 Grounding Electrodes.
- - (A) Electrodes Permitted for Grounding.
- - - (1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.
- - - - Exception: In industrial and commercial buildings or structures where conditions of maintenance and supervision ensure that only qualified persons service the installation, interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall be permitted as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system, provided that the entire length, other than short sections passing perpendicular through walls, floors, or ceilings, of the interior metal water pipe that is being used for the conductor is exposed.

Note: The 5 feet is referring to when the water piping is used as part of the grounding electrode system, not just for "bonding" of the interior metal water piping.

The reason is that, if used for the above purpose, beyond 5 feet inside the building, one could conceivably have a metal water pipe cut and repaired with a non-metallic fitting, thereby cutting the electrical path to ground out. The reasoning behind 'the first 5 feet' is that would be coming in through a wall and would be visible, allowing one to see if there was a problem with it.

Of course, though, the metal water piping *outside* is where it was likely cut off, with the metal water service pipe having been replaced with a PVC line - which means it is useless as a ground now anyway.

The above is referring to "grounding", not "bonding".