Imagine coming home to a cold house...

We live in an end unit of four townhouses and one gas line feeds two units, thus one at each end of the building.

After 35 years of marriage we don't buy things for each other anymore, but rather something for the home. This Christmas we decided to purchase a gas free-standing stove...(think wood stove but without having to go outside to chop gas).

Today is the installation day Part 1* Hurrah for us. OH NO!

Gas lines aren't suppose to spark are they 🤨 Apparently, there is stray current that is origination from our neighbors property. Oh and they are on an 🚙 RV vacation and won't be back until April. The local gas utility was called and removed our neighbors gas meter so the contractors could continue the installation.

Our neighbor will now need to hire a 'Sparkie' to remove the source of current that caused the spark (see what I did there?) prior to the gas meter being reinstalled.

WOW a real 💣 💥 waiting to happen!

It got me to wonder if some contractor, in following NEC 250.104 Bonding of Piping Systems and Exposed Structure. (A)Metal Water Pipe couldn't tell the difference between a water pipe and a gas pipe?


Wonder how long our building has had an electrically charged gas line?


*Part 2 is day two waiting for inspection and Part 3 is day three the final connections.

I hope that they have their water shut off, or there might be some very large issues when they return.

Doesn't get that cold in this area. Freezing pipes only happen with exposed to the outside elements. Hose Bibs et cetera are the only things of issue.

250.104 Bonding of Piping Systems and
Exposed Structural Steel

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
the service equipment enclosure; the grounded conductor at
the service; the grounding electrode conductor, if of suffi-
cient size; or to one or more grounding electrodes used. The
bonding conductor(s) or jumper(s) shall be sized in accor-
dance 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.

Not sure what you are getting at, but the gas line is normally going to be bonded by virtue of the equipment it serves being grounded. If not, then a separate ground must be run from the service entrance.

Further, it's NOT UNCOMMON to have current on the metallic gas or water lines serving a building because they are essentially both in parallel with all other buildings and in parallel with the electrical neutral out on the street. So there can be some circulating currents large enough to cause a spark. The thing though with gas services is they are usually plastic and there should be dielectric couplings in metallic piping to eliminate this. The gas company apparently knew that yours and you neighbor's lines are metallic and directly connected. (How old is your development?)

It could be that nothing is wrong or it is possible that ONE OF YOU has a compromised service neutral. I wouldn't be so quick to blame your neighbor.

-Hal

I found out more information after the original post that didn't get mentioned in the original post:

Built in 1970 with metallic piping. [see image] I the voltage is intermittent between 12v and 24v just what you would expect if a gas igniter was kicking on occasionally...perhaps a short somewhere in their equipment. The utility company removed their meter and left a note on their door explaining:

"The house pipe has stray current running on it which is electrically charging the meters. Have a service agency out to repair before we can re-install the meter."

"Voltage present" as measured to what?

-Hal

Let me help to define it for you in simple terms:

Again, measured from the neighbor's disconnected gas line TO WHAT??

I fail to understand why this is even an issue except that plumbers get their panties in a wad because this is a common situation with gas and water services. They think somehow there is a problem and a safety issue. It would be for someone cutting the piping if the potential was lethal, but 12-24 volts?

And there is no way that the igniter could cause this!

-Hal

Blather all you want but the Utility (Northwest Natural Gas) has tagged the system as "Hazardous" and removed the meter until such time as the hazard is no longer present.

Fine. Let's see what happens.

-Hal