Concentric Knockout & Seismic

[DansProfElec]

I was given a correction by the city inspector to install grounding bushings on 2 EMT screw connectors because we ran our 3/4" EMT through the 1" concentric knock outs of the subpanel (only the 3/4 knockout was removed). When I asked the inspector why we needed grounding bushings if there was a ground wire run in both EMT conduits, The inspector said the call is for seismic.

This is a 200 Amp subpanel in a commercial suite in California. Both 3/4" EMT's have #12 ground wires, running 2 20 Amp, 120 V circuits. All the EMT was secured to the concrete wall within 3 inches of the subpanel using strut.

Do you still have to install grounding bushings when using the concentric knockouts if you run a ground wire? If so what's the point of running a ground wire and bonding to all the ground screws in the j-boxes?

Can anyone site the code that says this.

Thanks,

Dan

 

[SEO]

Ask the inspector for a code section. Maybe it's a local requirement for earthquakes?

 

[e57]

I'm failing to see any reason for bonding for a 'siesmic' issue. What voltage is the panel? 120/240/208 then no bond is required... See 250.96/97

Did you not leave the envelope in the right restroom??? I AM KIDDING! As technically from a purley code stand-point even the EGG conductors are not required - unless by specification.

 

[infinity]

If this is really a code requirement I don't think that you'll find it in the NEC.