Grounding Service Panel to Gas Line

Inspected house today built in 1956. The panel had been update. The problem is there was a ground wire on the neutral connecting to a natural gas pipe below panel. There was also a rod in ground outside at the meter base. I did notice the gas line was bonded to the water heater cold and hot pipes. Did the electrician mistakenly think the cast iron gas line was a water pipe? This is the first time I had seen this.

It’s a bond connection

Bonding electrical panel to gas line ?

Yes sir.

The gas line was already bonded by the EGC run in the circuit feeding the furnace. Some areas require an additional bond. There is no problem as shown.

Thank You

I agree, not required but not specifically prohibited by the NEC either.

So gas pipe is bonded to panels grounded electrode ?

Keep in mind that in the 1956 NEC it stated " Section 2582 stated" and this home may have been constructed under that code cycle. Now I did not look at the image so I will only add this information for educational (history) purposes only. Yes, the Gas Lines are bonded to the electrical system if they are likely to become energized…

However due to the date given of the construction, see what the NEC said at that time in terms of using an underground gas line as an Electrode…

  1. Other Available Electrodes. Where a water system as described in section 2581 is not available, the grounding connection may be made to any of the following:
    a. The metal frame of a building, if effectively grounded;
    b**. A continuous metallic underground gas piping system.**
    c. Other local metallic underground systems, such as piping, tanks, and the like.

Concluding…we have come a long way BABY !

You know, that always perplexed me…
Even in the new construction around here, most AHJ’s require that the service is BONDED to the gas line. I know that bonding =/= grounding, but essentially by doing this one gets to use the underground gas piping as a really good grounding electrode. A really good in the sense of conductivity and dissipating transients and spikes; Maybe not good in terms of common sense.
I am NOT trying to start a grounding vs. bonding discussion :slight_smile:
Just sharing a stray thought…

I like that…sharing a STRAY thought…lol…

Well by virtue of making that connection to gas piping that is likely to become energized (keeping in mind that an EGC could serve this in most all cases rendering doing anything directly moot.) I believe with the gas meters and dielectric unions and what not associated with those I don’t really see it as being anything of a electrode…and since it is really a 250.104 thing lets just keep it as a bonding thing to lessen newbie confusion.

We also have to remember that bonding does not always equate to grounding as we see in Section 680.26 for pools and 680.74 hydromassage bathtubs but alas those are bonding planes and do not take the place of EGC’s and so on but lets not digress into that…unless someone has a question on those areas of the NEC…we all know I will elaborate on it if needed or I am sure Robert will or Jim as well.

HOWEVER…I do like a good Grounding versus Bonding discussion before my afternoon coffee break…plus sitting in an airport makes the time fly by much faster…:wink:


The metal gas lines are bonded to the grounding electrode system.

2017 NEC Bonding Requirement - 250.104(B)

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 any of the following:

(1) Equipment grounding conductor for the circuit that is likely to energize the piping system

(2) Service equipment enclosure

(3) Grounded conductor at the service

(4) Grounding electrode conductor, if of sufficient size

(5) One or more grounding electrodes used, if the grounding electrode conductor or bonding jumper to the grounding electrode is of sufficient size

The bonding conductor(s) or jumper(s) shall be sized in accordance with Table 250.122, and equipment grounding conductors shall be sized in accordance with Table 250.122 using the rating of the circuit that is likely to energize the piping system(s). The point of attachment of the bonding jumper(s) shall be accessible.

I realize this is an old thread but I thought I’d add the above to help anyone who comes across it in the future

Yup, agree with Juan. :smile: