On Monday, February 25, 2013 1:06:41 PM UTC-5, wrote:
On Mon, 25 Feb 2013 10:33:42 -0600, bud-- wrote: On 2/24/2013 12:29 PM, wrote: On Feb 24, 12:56 pm, wrote: On 2/24/2013 9:08 AM, wrote: But more commonly used is CSST, corrogated stainless steel tubing, which is a lot easier, faster, to work with. I recently took a continuing ed for electricians class. CSST came up because it has to be bonded to the earthing system. The instructor, an electrical inspector, has read quite a bit on CSST. It has caused fires as the result of nearby lightning strikes. The stuff can wind up at a far different potential that other nearby metal and arc to the metal, which can cause a hole in the tube. Instructor's comment was that if you are lucky the arc ignites the leaking gas. The alternative is an explosion. The question is who does the bonding. His recommendation was to not touch it; then you won't be named in the law suit. If electricians do bond it, follow the instructions exactly. Manufacturers have different instructions. The guy I sat next to had a house built and wouldn't allow CSST be used. I would use black pipe, copper/flare, or rigid copper pipe can be used if connections are hard-soldered (like silver solder). (May vary by jurisdiction.) Curious why there aren't similar problems with say copper tubing? I can see black iron pipe being more resistant to a lightning strike because it's large, thick and has a high melting point. But what about 3/8 copper tubing? Or is it that the ripples in the corrugated are a big part of the problem because they increase the impedance? CSST is really thin - far thinner than copper tubing. That is why even relatively large stuff (1") is so easy to run. An arc melt a hole in the thin material. Gas piping never used to be bonded to the electrical earthing system where it entered the house. (The NEC prohibits using gas service pipe as an earthing electrode.) I think all manufacturers now require a bonding connection at entry (was not required until recently). The instructor commented on a single 'near' lightning strike (OH) where 5 houses caught fire. At least a couple were 'properly' bonded. ===== Ask this old house recently had an episode where black pipe was run for gas. (I think it was, deja vu, for a patio BBQ, with a detachable outside connection.) Trethewey had an assortment of lengths, including many short sizes, and he didn't do any cut-and-thread. A run may have multiple pieces to get the right overall length. On mine I only needed one pipe cut and threaded - all the rest were stock lengths. I could have bodged it together with stock lengths, but would have added another 2 joints. minimum - and Home Despot does the cut and thread for free if you buy the pipe from them. I bought all the stock lengths elsewhwere for significantly better price, and just bought the one shorty from them.

In the US many locations don't allow copper. I'd go black iron to the outside, shutoff valve there, and flex stainless steel from there to the grill under the deck.