wrote
Hi all,
Am designing my shack, and I think I have a problem.Very near the
shack entrance is the entrance of my natural gas line to the house,
plus meter. Now I know I cant attach ground to gas line.... the
question is, how close can I get my rods? I plan to use 3, one right
outside the entrance, and the others 10 feet to either side. I dont
have the option of running away from the house more than 3-4 feet. The
first rod would be about 3-4 ft away from the gas line, but the ground
strap will have to go very very near the gas line. Am I looking at an
explosion in the event of a lightning strike? or will a few inches of
earth be enough insulation? I should point out that there appears to
be an aluminum ground rod driven into the ground at the same point the
gas line exits the earth. Thanks for any advice and information!

I am providing you some comments, and excepts, but your personnel safety in
these matters dictates that you obtain professional assistance, which I am
NOT.

1, Gas piping may NOT be the *primary* grounding electrode conductor.
2. Gas piping is REQUIRED to be bonded.

The ground electrodes you refer to installing outside your shack, these are
presumed to be the closest electrode connections for your station single
point ground? If so they must NOT be the same ground rod that will perform
the requirement of (minimum of two) lightning downconductors per structure,
or the grounding earth electrodes for those downconductors. But the station
single point ground MUST bond to the lighting protection system (AFTER) the
lighting downconductors have FIRST terminated at their OWN grounding
electrode or system thereof. The station single point ground must ALSO bond
to the home electrical service entry ground. You *should* discover your gas
piping is already bonded to the service entry ground in accordance with
code. But parts of the NEC and NFGC relating to this bond are fairly recent.
I strongly recommend you hire a licensed electrician who demonstrates
experience with lightning protection systems. If you come up dry on this
search after several telephone calls, start calling professional
(electrical) engineers who specify lightning protection systems. Call other
areas if you come up dry there.

A few excerpts related to your query:

Equipotential bonding of all metallic supply lines entering a building is a
vital requirement for protection of a building and its contents. Gas piping
systems are specifically required to be bonded to a grounding electrode in
accordance with the National Fuel Gas Code NFPA 54/ANSI Z223 and the
National Electrical Code ANSI/NFPA 70. The grounding electrode is a
requirement of the National Electrical Code.

The 1999 and 2002 editions of the National Fuel Gas Code require that "each
above ground portion of a gas piping system upstream from the equipment
shutoff valve shall be electrically continuous and bonded to any grounding
electrode, as defined by the National Electrical Code, ANSI/NFPA 70."
Bonding jumper shall be sized in accordance with NEC Table 250.66.

An equipotential bonding connection shall be made between the fuel gas
piping system and the electrical service grounding electrode. The bonding
jumper should be sized in accordance with NEC Table 250.66 (based upon the
rating of the largest overcurrent device protecting the feeder that supplies
the building - typically 200 amps). Bonding and grounding connections are to
be made by a qualified technician.

Hope this helps,

Jack Painter
Virginia Beach VA