# CSST bonding



## Jim Port (Oct 1, 2007)

This is a copy from the Wardflex site on CSST bonding.

4.10 ELECTRICAL BONDING AND GROUNDING
In accordance with NFPA 70 National Electrical Code (NEC) proper bonding and grounding of gas-piping systems
in a structure and the structure's electrical system is required by a qualified electrician. The requirement provides
an effective electrically continuous path in an effort to conduct stray voltage/current safely to ground. The NEC
also states that it is good practice to bond all metallic systems and objects. In accordance with these requirements,
WARDFLEX requires the gas-piping system to be bonded to the electrical earth grounding system of the structure
through the use of a bonding clamp and wire.
l The bonding point must be in as close proximity to the electrical panel as practical; close proximity of
the bonding point to the gas meter is also desirable.
l The wire gauge for this bond must be sized, at a minimum, for the full amperage available through the
electric service.
l Further minimizing impedance over the bonding assembly is desirable. The NEC should be referred to
for additional requirements and specific techniques for bonding and
grounding.
For attachment to the WARDFLEX gas piping system, bonding clamps must
be attached to the WARDFLEX brass fitting, to a steel manifold, or to a rigid
pipe component connected to a WARDFLEX fitting. The corrugated stainless
steel portion of the gas piping system shall not be used as the bonding attachment
point under any circumstance. The WARDFLEX flexible gas piping or
other gas system components shall not be used as a grounding electrode or as
the grounding path for appliances or electrical systems. Bonding and grounding
requirements are also contained in NFPA 54 National Fuel Gas Code.
NFPA specifically requires: “each above ground portion of a gas piping system
which is likely to become energized shall be electrically continuous and bonded to a designed, permanent, low impedance effective ground fault current path.”

Now is this calling for the bond to be sized based on the Table 250 value, a Table 310 value or something else? It just seems so overkill considering the NEC allows the EGC for the circuit to bond gas lines.

A secondary question would be would the CSST be considered bonded by the EGC connection at the appliance?


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## A/A Fuel GTX (May 6, 2009)

Jim Port said:


> This is a copy from the Wardflex site on CSST bonding.
> 
> 4.10 ELECTRICAL BONDING AND GROUNDING
> In accordance with NFPA 70 National Electrical Code (NEC) proper bonding and grounding of gas-piping systems
> ...


I have always used a #6 CU for CSST bonding. That is what Gastite specifys anyway. CSST is not considered bonded by the EGC of the appliance.


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## wendon (Sep 27, 2010)

250.104 (B) is the code on bonding metal gas piping. The issue with the CSST is that it needs to be bonded where it is coupled to the steel gas line. The stainless steel pipe is a poor conductor of electricity and can get pin holes burned in it from a lightening strike. If you sized it off table 250.122 #6 wouldn't #6 be fine for a 200 amp service?


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## Dennis Alwon (May 9, 2009)

IMO, it is meant to call for a wire based on 250.66, however the way it is worded would mean the same size as your service conductors.

CSST must be bonded independently of the egc at the point of entry into the building based on gas codes.


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## Dennis Alwon (May 9, 2009)

Here is the law



> 7.13.1 Pipe and Tubing Other Than CSST. Each aboveground portion of a gas piping system other than CSST that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping other than CSST shall be considered to be bonded when it is connected to appliances that are connected to the appliance grounding conductor of the circuit supplying that appliance.
> 
> 7.13.2 CSST. CSST gas piping systems shall be bonded to the electrical service grounding electrode system at the point where the gas service enters the building. The bonding jumper shall not be smaller than 6 AWG copper wire or equivalent.


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## Jim Port (Oct 1, 2007)

Dennis Alwon said:


> IMO, it is meant to call for a wire based on 250.66, however the way it is worded would mean the same size as your service conductors.


That is one way of reading those instructions, but I did not want to skew the replies. A 4/0 to bond a gas line makes little sense.


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## Dennis Alwon (May 9, 2009)

Jim Port said:


> That is one way of reading those instructions, but I did not want to skew the replies. A 4/0 to bond a gas line makes little sense.


I agree 4/0 makes no sense. I always cover my butt and install it based on 250.66. That is what Omegaflex calls for so I figured I can't go wrong.


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## Dennis Alwon (May 9, 2009)

Interesting info on Wardflex-- this is from their* site of FAQ's*

BONDING AND GROUNDING FAQs 
For additional information regarding CSST Bonding and CSST Safety, please visit: www.csstsafety.com
Q: Is WARDFLEX required to be bonded?
A: Yes, WARDFLEX CSST must be bonded.

Q: Is WARDFLEX considered bonded if it is connected to an appliance?
A: Yes, according to NFPA 54 section 7.13, the gas-piping system “…shall be considered bonded when it is connected to appliances that are connected to the appliance grounding conductor of the circuit supplying that appliance,” but Ward Manufacturing also requires supplemental direct bonding.

Q: Should WARDFLEX be directly bonded using a bonding clamp and wire routed so as to provide an electrically continuous path to ground?
A: Yes, Ward Manufacturing requires a supplemental direct bond. There are several methods that can be used to meet the installation requirements. See Technical Bulletin 2008-1, WARDFLEX® CSST Electrical Bonding for details.

*Q: What size jumper wire is required for direct bonding?
A: A minimum of a number 6 AWG copper wire is required for direct bonding .
*
Q: What type of bonding clamp should be used?
A: Any UL-467-approved bonding clamp can be used.

Q: How far away from the electrical service panel should the bonding clamp be placed?
A: The bonding clamp should be placed as close as possible to the electrical service panel.

Q: How many bonding connections are required per installation?
A: A minimum of one (1) bond on the consumer outlet side of the gas meter is required per system.

Q: Can a separate grounding electrode be installed to bond the WARDFLEX® CSST system?
A: No. The WARDFLEX® CSST system is required to be bonded to the electrical service grounding system. The use of an independent grounding electrode could cause a difference in potential between the gas piping system and other metallic systems in the structure that are tied to the electrical service grounding system. This difference in potential could allow arcing to occur. In cases where no other options are present, a secondary grounding electrode may be installed but must be connected to a common grounding electrode conductor (i.e. electrical service grounding electrode) per the requirements of the National Electric Code.


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## Jim Port (Oct 1, 2007)

The newer versions like Counterstrike don't seem to have the same issues as the yellow clad CSST.


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## Dennis Alwon (May 9, 2009)

Jim Port said:


> The newer versions like Counterstrike don't seem to have the same issues as the yellow clad CSST.


That's correct but according to the state of NC and as I read the rule- you still have to bond the counterstrike. Wardflex has the wardflex 2 pipe but it still needs the extra bond by the gas code.


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## frenchelectrican (Mar 15, 2007)

Our European codes do required that we use 16mm2* or larger for bonding purpose on CSST gaz tubings it pretty much simair to the Americian verison.

Merci,
Marc


* 16mm2=6 AWG


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