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Monday, February 7, 2022
Question:
Good Morning,
My partners and I are having a debate about whether a liquid-tight flexible metallic conduit is permitted to be used as an equipment grounding conductor. Your input may help solve this debate.
Thank you.
Ronnie Jones
A
Answer:
Hi Ronnie,
Thanks for the question. Listed liquid-tight flexible metal conduit shall be permitted to be used as an equipment grounding conductor in accordance with the limitations in Section 250.118(6). Check out NEC Sections 350.6, 350.60, and 250.118(6) which indicates that LFMC used as an EGC must be terminated in listed fittings. For trade sizes, 3∕8 through 1∕2, the circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less. For trade sizes, 3∕4 through 11∕4, the circuit conductors contained in the conduit are protected by overcurrent devices rated not more than 60 amperes and there is no flexible metal conduit, flexible metallic tubing, or liquid-tight flexible metal conduit in trade sizes 3∕8 through 1∕2 in the ground-fault current path. The combined length of flexible metal conduit and flexible metallic tubing and liquid-tight flexible metal conduit in the same ground-fault current path does not exceed 6 ft. If used to connect equipment where flexibility is necessary to minimize the transmission of vibration from equipment or to provide flexibility for equipment that requires movement after installation, an equipment grounding conductor shall be installed. So quite a few conditions to meet. Hope this helps with your debate.