After having a discussion about this, grounding to the electrical system is rarely seen or practiced in our area. The gas meters are grounded and bonded to a grounding rod.
Since the system is connected to the meter, and the meter grounded, would this be a sufficent source of grounding?
The gas system must be bonded to the main panel ground bus or to the electrical system grounding electrode. It CANNOT be bonded to a separate electrode.
More info: http://www.nachi.org/forum/f2/good-corrugated-stainless-steel-tubing-bonding-illustration-55769/
Water piping can be used as the GES, but gas piping cannot be used as the GES, nor can it be used as a primary path from the service equipment to the grounding-electrode.
Metallic piping (gas or water) is not “grounded” (even though it may appear to be so), it is “bonded” to the electrical system. The electrical system is “grounded.”
Are you saying that a water pipe can be the only grounding electrode?
What would be the difference when bonding to a grounding electrode that services the panel or bonding to a competely seperate grounding rod next to the meter?
Please clarify. Normally, there is only one electrode (a driven rod) at the meter or main panel (which should be near the meter).
Often times it is, in existing construction. Codes are not retroactive so there’s no requirement to add a supplemental electrode.
Bonding to a separate electrode does not bond the system to the electrical service.
8ft rods are actually poor grounds but considered adequate for the intended purpose. True ground is achieved around a depth of 200ft as explained to me by a guy that used to work for a power company in a division related to high power distribution.
The goal of bonding the gas pipe is “equipotential” with the electrical ground and that can not be achieved with two different rods.
Lightning induced arcing can jump from “ground to ground” since there are differences in potential.
I’d still call it out on a home inspection. Here’s the IRC and the commentary (I realize ya’ll don’t go by that in the Republic of CA ;-)).
E3608.1.1 Metal underground water pipe. A metal underground
water pipe that is in direct contact with the earth for 10
feet (3048 mm) or more, including any well casing effectively
bonded to the pipe and that is 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, shall be considered
as a grounding electrode (see Section E3608.1). Interior
metal water piping located more than 5 feet (1524 mm)
from the entrance to the building shall not be used as part of the
grounding electrode system or as a conductor to interconnect
electrodes that are part of the grounding electrode system.
** Commentary:** Any metal water pipe in contact with the earth for 10 feet
(3048 mm) or more is considered a grounding electrode.
It is often thought that only the main water service piping
fits this description, but any metal water pipe, such as an
irrigation pipe or pipe from a water well, if buried in the
earth for 10 feet (3048 mm) or more, must be bonded as
part of the grounding electrode system. The pipe could
be of any material such as copper or steel because the
code does not mention the type of metal. In many
houses, a water meter, water-pressure reducing valve,
or similar equipment is installed in the water supply line.
A bonding jumper of the same size as the grounding
electrode conductor is installed around such devices because
many of these devices are made of
nonconductive materials. In many cases, when the device
is removed and/or replaced, the grounding electrode
is disconnected. A useful practice is to leave
enough slack in the bonding jumper around the device
that the jumper will not have to be taken off the piping in
the event the device is replaced.
The code assumes that the first 5 feet (1524 mm) of
water piping, measured from the point that the piping
penetrates an outside wall or floor slab on grade, will not
be disturbed or altered by plumbing work. Any piping beyond
5 feet (1524 mm) into the building is more likely to
be altered such that electrical continuity is lost. This alteration
could take the form of the installation of plastic piping,
nonconductive components (e.g. water filters), dielectric
fittings or the removal of grounding clamps.
**A supplemental grounding electrode is always
required when a water pipe electrode is used. **The most
commonly used supplemental grounding electrode is the
ground rod. That is why in so many dwellings a grounding
electrode conductor is run from the service equipment
to the entry point of the water pipe and another
grounding electrode conductor is run to a ground rod.
The ground rod is quite often driven into the ground close
to the service equipment. A grounding electrode conductor
that connects the service equipment to a ground rod,
pipe or plate electrode and connects to no other elec-
trodes is not required to be larger than size 6 AWG copper
or 4 AWG aluminum (see note to Table E3603.1 and
Section E3610.2).
Here in most cases the gas meter is not close to the panel so both the ouside meter or panel has a grounding rod, and also the gas meter itself has a seperate grounding rod.
My question is since both systems use the same type of grounding style would the gas meter grounding rod be as satisfactory as the one for the electrical service? If not then why?
That seems to be the accepted practice in our area.
When you said meter, I thought you meant the electric meter. My bad.
It’s wrong because the code says it’s wrong. CSST must be bonded to the main panel bus or to the house GES ground rod. Period.
It’s up to you to point out the “accepted practice” is incorrect by citing it as a defect and proving it with the code when challenged.
I answered that in post #9
You’re missing the point Sean. The gas lines are not GROUNDED, they are BONDED (to the electrical service). Read Bruce’s post.
There is no need to “ground” the piping. Only the electrical system needs to be “grounded.”
Here, I found the reason from gastite
Proper bonding and grounding will reduce the risk of damage and fire from a lightning strike. Lightning is a
highly destructive force. Even a nearby lightning strike that does not strike a structure directly can cause all
electrically conductive systems in the structure to become energized.** If these systems are not adequately**
bonded, the difference in electrical potential between the systems may cause the charge to arc from one
system to another. Arcing can cause damage to CSST. Direct bonding and grounding as set forth above will
reduce the risk of arcing and related damage over a non direct bonded system.
BTW gastite has a product called flashshield. They say this tubing does not need to be bonded.
Actually I do not think bonding to a water pipe would be a good idea unless you can confirm that the water pipe is all conductive leading to the electrical ground.
The communication industry stopped allowing conductors to be bonded to water pipes years ago.
It’s a terrible idea, that’s one of the reasons it is no longer used. Many systems lost their CES as soon as the home was re-piped. Not all plumbers know what that silly clamp is for…
Good reminder to check for that water meter jumper wire.
