I do a lot of rural inspections. Sometimes I see the gas meter grounded with a rod, sometimes I don’t. Just curious if I should call this out? does it need to be grounded or bonded. If its bonded inside, from the water heater to the natural gas supply does it need to be grounded outside? Or is this ok depending on when the house was built.
Thanks.
The bonding of gas at a water heater is a code violation. The bonding of hot and cold at the water heater is a code violation.
250.104 is where we find the rules for bonding metal pipes in a building. This section clearly states that any bonding is to be done to the service equipment, the neutral at the service, or to a grounding electrode not to the pipes at a water heater.
Any and all ground rods driven must be bonded together to form the grounding electrode system. To just drive a rod for the gas meter is a code violation.
Would you expand on this Mike? I often see a bonding connection at the water heater, connecting hot, cold and gas.
(B) Other Metal Piping. Where installed in or attached to
a building or structure, a metal piping system(s), including
gas piping, that is likely to 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 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
is likely to energize the piping system(s). The equipment
grounding conductor for the circuit that is likely to energize
the piping shall be permitted to serve as the bonding
means. The points of attachment of the bonding jumper(s)
shall be accessible.
Never mind Mike, I get what you were saying here. I thought you were referring to “bonding jumpers” as being a violation, when it appears you meant that the main-bonding must be at the service, service neutral or GE.
**250.104 Bonding of Piping Systems and Exposed Structural Steel. **
(A) Metal Water Piping. The metal water piping system shall be bonded as required in (A)(1), (A)(2), or (A)(3) of this section. The bonding jumper(s) shall be installed in accordance with 250.64(A)](http://code.necplus.org/document.php?field=jd&value=necss:70-2011:id02011004096#70-2011:id02011004096), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.
(1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to
(1)the service equipment enclosure,
(2)the grounded conductor at the service,
(3)the grounding electrode conductor where of sufficient size,
(4)or to the one or more grounding electrodes used.
The bonding jumper(s) shall be sized in accordance with Table 250.66](http://code.necplus.org/document.php?field=jd&value=necss:70-2011:id02011004136#70-2011:id02011004136) except as permitted in 250.104(A)(2)](http://code.necplus.org/document.php?field=jd&value=necss:70-2011:id02011004302#70-2011:id02011004302) and (A)(3)](http://code.necplus.org/document.php?field=jd&value=necss:70-2011:id02011004305#70-2011:id02011004305).
(B) Other Metal Piping. If installed in, or attached to, a building or structure, a metal piping system(s), including gas piping, that is likely to become energized shall be bonded to
(1)the service equipment enclosure;
(2)the grounded conductor at the service;
(3)the grounding electrode conductor, if of sufficient size;
(4)or to one or more grounding electrodes used.
The bonding conductor(s) or jumper(s) shall be sized in accordance with 250.122](http://code.necplus.org/document.php?field=jd&value=necss:70-2011:id02011004434#70-2011:id02011004434), using the rating of the circuit that is likely to energize the piping system(s).
The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.
I broke down the requirements for bonding metal pipes into four places as outlined in the code section that applies.
Sub part (B) addresses the gas pipes and if bonded it must be bonded to the same four places. If this bonding is being done due to the installation of CSST then the same four places are the only code compliant points.
Way back in the 70s there was a requirement to make all metal pipes installed electrically continuous. This was removed from the electrical code in the late 70s or early 80s. The electrical code making panels realized that they had no power over the installation of water or gas piping systems and those codes allowed the installation of non-metallic piping systems and/or repairs.
It became a standard of practice to install a bonding jumper from hot to cold and then to the gas pipe but the installation is not compliant to the rules of the code.
Here is a good example of how wrong this can be. We bought our home in 1994 and it had the copper water pipes bonded at the point where it entered the building with a bare #4 copper bonding conductor. The hot was bonded to the cold at the water heater but at some point an icemaker line was installed. The plumber installed about 12 inches of CPVC pipe with a tee to supply the icemaker line. This CPVC was between the #4 bonding jumper and the water heater rendering the bond between the hot and cold useless.
As a certified electrical inspector for the state of NC I will not accept a bonding jumper installed between the hot and cold at a water heater. I also know that the hot and cold is part of the same potable water and does not constitute two separate metal water piping systems but just for the sake of this discussion let’s say they are two separate systems then each would be required to be bonded back to one of the four points outlined in the code section above.
Being that most electrical inspectors know that the hot and cold does not constitute two separate systems nothing is ever said about the bonding at the water heater thus the SOP of doing so still exist today.
From the 1975 cycle of the NEC
Would this be correct?
New house in SC, copper gas piping with some CSST appliance connectors.
Typical equipment ground connected to the gas furnace cabinet with the gas valve/gas pipe in the cabinet bonded to the cabinet.
Has a 6 ga copper conductor from the main gas pipe at the gas meter running to a subpanel.
The main panel was near the gas meter and they chose to run the additonal bond conductor all the way across the house to the sub panel.
I reported that the existing bond could remain but recommended another one be installed from the main gas pipe to the main GEC or existing ground rod.
You made a good call, keep up the good work
Mike any clarification or change on this in the 2014? Not that I’m disagreeing with you based on the way this is currently written but your opinion is well in the minority. 
As far as I know the wording is the same.
Next week I will be spending a lot of time with some well known folks in the electrical trade and some of those fine folks are the ones who have pointed me in this direction.
I hope to see Roger and Dennis next week also.
That’s not a ground wire.
It’s a trace wire.
Yep. :roll:
Thanks guys!
What is a “trace wire” used for?
The trace wire is used to identify the path of underground plumbing (gas or water). The trace wire is buried with the target plumbing. A signal generator is attached to the exposed wire end and a sensor (similar to a metal detector) can then sense the path of the signal through the “trace wire,” thereby ‘mapping’ the underground plumbing. A fairly crude description but you should get the general idea.
Thanks Bob!
I read reputable online sources that say the gas meter cannot be bonded to its own ground rod–it must be bonded to the house GEC with #6 copper at a length no greater than 75’. Fine.
However,
I find zero vetted documentation that explains why the gas meter cannot be bonded to its own ground rod. I believe the intent of the restriction is to prevent the gas line(s) from serving as a potential pathway to ground–but who cares what I believe.
I find zero vetted documentation that explains how one bonds the gas meter to the house GEC in instances where such bonding requires greater than 75’ of #6 copper.
Two different electrode could have a potential difference between them. The NEC requires all electrodes to be bonded together. Gas lines are prohibited from being used as an electrode.
There are many good sources of information related to electrical system design. The Standard Handbook for Electrical Engineers, The American Electricians Handbook, and the IEEE Color Book Series are all reliable sources for learning why things are done as they are. The NEC is not. The main function of the NEC is to set installation standards. In other words, it is main function is to describe how things are done, not why things are done as they are.
