CSST Bonding

[texie]

Since the issue of CSST bonding has come up often recently, I thought this article from EC&M Magazine might be of interest to the forum. It can be found here: http://ecmweb.com/bonding-amp-grounding/whose-job-it-bond-corrugated-stainless-steel-tubing-csst

 

[Dennis Alwon]

Thank you

 

[Ponchik]

good article. Thanks :thumbsup:

 

[renosteinke]

Alas, the article simply continued my confusion on the issues - both the issue of CSST, and the general issue of grounding the gas system.

Yes, I said 'grounding.' Let me use an example ...

I saw that the local McDonald's had a ground clamp attached to the output piping at the gas regulator. The GEC (#4 copper) disappeared directly into the ground. I assume that it went on to connect to the grounding electrode system.

So ... is this now expected? When I do a service change, am I expected to continue my GEC from the ground rod, or the main panel buss, to the gas piping where it enters the building? The article only discusses the bonding at appliances.

As for CSST ... do I simply bond the piping to my conduit on either side of the CSST - or need I also run a solid copper wire along the CSST, connecting the solid piping on either end?

Finally, since I'm worried about lightning, and not the usual fault currents ... do I size this bond to 250.66 or to the other table (122?). What if I have a Ufer as my grounding electrode? Would #6 be enough, or will I wind up using 3/0?

 

[kwired]

I was happy to read this part -

Proposals to include specific bonding requirements for CSST gas piping systems in the 2011 NEC were rejected by NEC Code-Making Panel 5 on the grounds that lightning protection for gas piping systems is beyond the scope of the NEC. “The mitigation of the effects of lightning is a design option,” reads the rejection. “The purpose of the NEC is the practical safeguarding of persons and property from hazards arising from the use of electricity.”

As it has always been my opinion that this bonding requirement was specific to the product and is the product installer's issue, not the electrician's issue. We are now supposed to install an intersystem bonding device - they are welcome to connect to it - other systems is exactly what it is for.

I am in total disagreement of this statement-

“Electricians already bond the copper water pipe and the structural steel exactly the same way we recommend bonding the corrugated tubing,” says Robert Torbin, director of codes and standards for Exton, Pa.-based flexible metal hose manufacturer OmegaFlex.

Structural steel maybe is a little closer to the way they want, water piping is not. Plus if we have a continuous metal piping even if it changes from steel to copper, one bond to the piping system gets the whole system - we do not do anything additional unless there is a dielectric fitting involved, and even then we just jumper the insulating fitting instead of running a new bonding jumper all the way to the grounding electrode system.

If I have "yellow jackets" in the house I usually try to get rid of them.

 

[lakee911]

If I have "yellow jackets" in the house I usually try to get rid of them.

Me too. Just stay away from the bad product (IMHO). Problem solved.

 

[renosteinke]

We've avoided the issue. Let's retreat a bit ...

I'll use a certain commercial job as an example. In that building, the gas immediately transitioned to CSST as soon as it entered the building. The CSST ran without splice or connection about 120-ft, up walls and across ceilings, until it arrived at the furnace. There were no other gas appliances on this line.

Now ... I consider the furnace 'end' to be bonded by way of the appliance, and the 3-prong code for the igniter. It's the rest of the run that has me confused.

Was I supposed to run a ground to the gas piping at the start of the run? Would a length of #12 to a nearby 4-square be enough? Could I just beam-clamp a jumper to the nearest I-beam? Or, do I need a #6, in pipe, all the way back to the service?

Likewise, am I expected to run a ground wire (what size?) along the length of the CSST, thus bonding the two sections of 'hard' pipe together?

 

[Gregg Harris]

We've avoided the issue. Let's retreat a bit ...

I'll use a certain commercial job as an example. In that building, the gas immediately transitioned to CSST as soon as it entered the building. The CSST ran without splice or connection about 120-ft, up walls and across ceilings, until it arrived at the furnace. There were no other gas appliances on this line.

Now ... I consider the furnace 'end' to be bonded by way of the appliance, and the 3-prong code for the igniter. It's the rest of the run that has me confused.

Was I supposed to run a ground to the gas piping at the start of the run? Would a length of #12 to a nearby 4-square be enough? Could I just beam-clamp a jumper to the nearest I-beam? Or, do I need a #6, in pipe, all the way back to the service?

Likewise, am I expected to run a ground wire (what size?) along the length of the CSST, thus bonding the two sections of 'hard' pipe together?

The requirement for the bonding is through the manufacture of the CSST installation guide and it sends you to the fuel gas codes.

NFPA 54 National fuel Gas Code 7.13.2 CSST
CSST gas piping systems shall be bonded to the electrical service grounding electrode system. The bonding jumper shall connect to a metallic pipe or fitting between the point of delivery and the first downstream CSST fitting. The bonding jumper shall not be smaller than # 6 AWG copper wire or equivalent. Gas piping systems that contain one ore more segments of CSST shall be bonded in accordance with this section.

The following Article and section do not apply to CSST. The equipment grounding conductor is to small to comply with the # 6 AWG copper requirement.


250.104 (B)
(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 sufficient size; or to one or more grounding electrodes used. The bonding conductor(s) or jumper(s) shall be sized in accordance 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.


The job you are referencing is commercial. You could bond the downstream side of the gas meter (load side) or before the first CSST fitting if it is closer to the electrical service. Now if the building is steel framed and would be part of the Grounding Electrode System it could be bonded to the steel or any other electrode that is part of the GES as referenced in 250.50. and would be sized using 250.66

 

[don_resqcapt19]

The problem I have with the CSST bonding is that there is no technical substatiation to support the idea that the #6 bonding conductor will solve the problem. The lack of any technical substatiation is the real reason that you don't find this bonding rule in the NEC.

 

[don_resqcapt19]

...The following Article and section do not apply to CSST. The equipment grounding conductor is to small to comply with the # 6 AWG copper requirement.
...

As far as the NEC is concerned that {250.104(B)} is the only section that applies. I agree that other codes and the manufacturer's instructions require the #6 bonding conductor.

 

[renosteinke]

Thank you, and thanks especially for the Fuel Gas Code excerpt!

So ... since CSST is / may / will be present .... is it advisable (or would REQUIRED be the word) to bond the gas line at the meter, on the customer side, to the grounding electrode system?

I just did a (residential) service change, and the inspector got this queasy look when I asked about running a GEC from the nearby gas meter to the nearest ground rod. The plumber (3rd year apprentice) got all agitated saying "No!"

I see this as a significant change to the way we do service changes.

Don, it may not be an "NEC" issue - yet. Our code folks try real hard to 'harmonize' with the other codes (especially other NFPA codes, like the Fuel Gas code).

Not that it matters; we are required to follow ALL codes, not just the NEC.

In my upcoming remodel, I expect there to be quite a dispute between the plumber and I regarding his desire touse CSST

 

[Gregg Harris]

The problem I have with the CSST bonding is that there is no technical substatiation to support the idea that the #6 bonding conductor will solve the problem. The lack of any technical substatiation is the real reason that you don't find this bonding rule in the NEC.

There has been third party testing and a joint venture between the NFPA Standards Council, the CSST manufactures, National Fuel Gas codes, NEC, NFPA CSST Task Group and others to substantiate the findings. A leter was just released by NFPA on August 30th 2012 in reference to this subject matter and is posted on the NFPA website.

All of the third party testing reports that I have reviewed shows a marked improvement using the # 6 copper bonding for up to 200 amp services.

Two of the six manufactures have developed a black carbon composite covering that dissipates the current strike. Both still require the bonding at this point, and a code change proposal has been submitted to not require the bonding for the specific product. I would rather see the requirement stay in place along with another new proposal to reword 250.104 (B) that was submitted.

 

[don_resqcapt19]

There has been third party testing and a joint venture between the NFPA Standards Council, the CSST manufactures, National Fuel Gas codes, NEC, NFPA CSST Task Group and others to substantiate the findings. A leter was just released by NFPA on August 30th 2012 in reference to this subject matter and is posted on the NFPA website.

All of the third party testing reports that I have reviewed shows a marked improvement using the # 6 copper bonding for up to 200 amp services.

Two of the six manufactures have developed a black carbon composite covering that dissipates the current strike. Both still require the bonding at this point, and a code change proposal has been submitted to not require the bonding for the specific product. I would rather see the requirement stay in place along with another new proposal to reword 250.104 (B) that was submitted.

It does not appear that the third party testing ever took place
http://www.nfpa.org/Assets/files/AboutTheCodes/54/FD12-8-56D12-15_NFPA 54_CSST.pdf
The only real solution is for the plumbing codes to ban this product.

 

[infinity]

For anyone interested here's the NJ requirment for bonding, starts on page 10:
,
http://www.state.nj.us/dca/divisions/codes/publications/pdf_ccc/ccc_2011_spring.pdf

 

[Gregg Harris]

It does not appear that the third party testing ever took place
http://www.nfpa.org/Assets/files/AboutTheCodes/54/FD12-8-56D12-15_NFPA 54_CSST.pdf
The only real solution is for the plumbing codes to ban this product.

There has been a bunch of independent studies done to date, This joint one is still a work in progress.

The product is safe, if installed with consideration for integrity and is bonded.

 

[don_resqcapt19]

...The product is safe, if installed with consideration for integrity and is bonded.

I have seen nothing to convince me that the product is safe, even with the bonding. Do you have links to these studies, and more importantly, who paid for the studies?

 

[kwired]

As far as the NEC is concerned that {250.104(B)} is the only section that applies. I agree that other codes and the manufacturer's instructions require the #6 bonding conductor.

Exactly why I think it should be the installers responsibility to bond it. If they want to be experts in what they do, then this is just a part of using that product that they need to learn about. We are now supposed to have an intersystem bonding jumper - there is no reason for them to have to enter a panel to connect it to the electrical system.

I have seen nothing to convince me that the product is safe, even with the bonding. Do you have links to these studies, and more importantly, who paid for the studies?

Same here.

 

[renosteinke]

Time for a reality check.

Looks like I should have run a wire to the gas meter when I did my latest service change. OK, maybe there's no CSST today - but who can speak to tomorrow? Might as well get it over with.

Case in point: My 1957 house just had the gas line to the water heater (in the carport) rust through. In such a repair, I expect many guys would simply cut the pipe, thread the ends, and use a length of CSST. Remember: they're not allowed to use unions under the house, and taking the line apart from the end is a lot more work!

I can't expect the plumber, or the HVAC guy, or whoever installs an appliance and adds in a length of CSST to also go to the gas meter and trench to the ground rod. (Remember, the ground rod may be completely buried). If they do, they're more likely to bang in one of those little "data" ground rods and never connect it to the existing grounding network at all.

Just run a wire to the intersystem block on the outside of the panel? Yea, right .... to be removed by a copper thief before the serviceman's truck clears the driveway.

No, the gas meter is usually fairly close to the electrical service. I expect the 'practical' thing to do is to extend your GEC (or run an additional GEC) from one of your ground rods to the gas piping. If it's new construction and you're making a UFER, just bond the gas pipe to the rebar.

Infinity, thanks for the link - the artwork was especially nice.

A final note: since lawn mowers and copper thieves both prooved hazardous to exposed GEC's, places began requiring the things to be #4 solid wire, and then wanted them in pipe. That complicates the installation quite a bit.

Looks like I have some digging & bending in my future.

 

[Gregg Harris]

Case in point: My 1957 house just had the gas line to the water heater (in the carport) rust through. In such a repair, I expect many guys would simply cut the pipe, thread the ends, and use a length of CSST. Remember: they're not allowed to use unions under the house, and taking the line apart from the end is a lot more work!


Neither fuel gas code restricts the use of unions in a crawl space, only in concealed locations, with the exception in the National fuel Gas Code that will allow a repair in a concealed location to use a union and center punch the retaining nut to prevent it from backing apart.


In your scenario of black pipe and adding a section of CSST to a stationary piece of equipment a # 6 copper conductor or equivalent would need to be run to bond the CSST back to the Grounding Electrode System.

 

[renosteinke]

I've seen the rule (UMC? UPC?) and it's pretty blunt: NO unions under houses. I'll have to run it down and find the exact text.

You get my point about the need for the GEC should the repair be made with CSST, though. I don't see anything in the CSST specs that suggests that the connection has to be made near the CSST. So - with the New Jersey artwork in mind- we might as well add it when we do a service.