356.60 Equipment Grounding Conductor for LFNC

[cowski]

I'm switching some LFMC to LFNC. The LFMC is producing a nice eerie creaking noise that I'd like to eliminate.

Can someone explain the equipment grounding conductor specified by 356.60? There is already a green grounding conductor running through the LFMC. Is that conductor technically redundant? I've never seen LFMC run without a ground...but I'm getting the sense that it's only required for LFNC.

Is it wrong to run a grounding conductor through LFMC? Could it cause a ground loop? Do you have to bond the LFMC to each box with special bonding fittings if you aren't running a ground conductor?

 

[infinity]

Take a look at 250.118 for when an EGC is required in LFMC.

 

[Rock86]

As per 2017 NEC... if your situation requires the additional EGC, then that may be why it was installed originally.

 

[cowski]

Thanks Rob.

Right, 250.118 (5) (e) requires an ECG if the equipment will be moved (which is our case).

"If a wire-type ECG is installed in a metal raceway and it is not isolated per 250.96(B), the raceway is in parallel with the wire and the combination of the metal raceway and the wire is the EGC..."

So we keep the ECG that we have and can switch to LFNC.

 

[cowski]

Thanks Rock