Bonding Required For Liquidtight Flexible Metal Conduit

[AungYe]

Hi,
We are installing immersion heaters and we have (3)1-1/4" RGS conduits running from control panel to immersion heaters. We use Liquidtight Flexible Metal Conduit before termination to the heaters. Each conduit has ground in it. However, the residence engineer is asking for bonding between the RGS and the immersion heater. According to Article 250.118(6), EGC has been installed inside the conduit. Do we still need bonding along the Liquidtight Flexible Metal Conduit?

Thanks.

 

[infinity]

IMO no. The RMC is bonded on one end and depending on the circuit size within the LFMC it already may be bonded on both ends. Look at 250.118 for LFMC as an EGC.

 

[Ponchik]

The LTFMC is bonded at both ends. You are not using the flexible conduit as an EGC so IMO the 250.118 does not apply, but I agree with infinity the external bonding is not required.

The designing engineer could be the AHJ, so you may have to install per his/her design requirements.

 

[don_resqcapt19]

Hi,
We are installing immersion heaters and we have (3)1-1/4" RGS conduits running from control panel to immersion heaters. We use Liquidtight Flexible Metal Conduit before termination to the heaters. Each conduit has ground in it. However, the residence engineer is asking for bonding between the RGS and the immersion heater. According to Article 250.118(6), EGC has been installed inside the conduit. Do we still need bonding along the Liquidtight Flexible Metal Conduit?

Thanks.

That is the common practice for industrial work around here and has been since I started in 73. They always specify the internal wire type EGC and an external bonding jumper around the LFMC. It is not required by the NEC, just required by the project specifications.