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Tuesday, February 28, 2017
Question:
Re: CQD answer published Monday, February 20, 2017 -Bonding Other Piping
Charlie, reading the answer to the gas pipe bonding question raised another question. How do we know when piping of any type would be likely to get energized and need to be bonded?
Patrick
A
Answer:
Hey Patrick thanks for your question. Unfortunately the phrase "likely to become energized" is not defined in the NEC but it is described in Annex B of the 2015 NEC Style manual as "failure of insulation on". The NEC Style Manual can be downloaded at:
http://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards?mode=code&code=70
So if a metal piping system, other than water piping systems covered by 250.104(A), is connected to equipment that contains insulated conductors it would be considered likely to become energized because an insulation failure could occur. If the other piping system was not connected to equipment that contained insulated conductors it would not be considered likely to become energized. As stated in the previous answer in most cases the bonding is inherently provided by the equipment grounding conductor connected to the equipment.