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NEC Grounding Question - Grounding of CT Metering Enclosures

NEC Grounding Question - Grounding of CT Metering Enclosures

NEC Grounding Question - Grounding of CT Metering Enclosures

This seems like a simple question, but it always generates confusion - at least with me.

For a separate, stand-alone CT Metering cabinet that is remote from the main service disconnecting means, is there a requirement to run an equipment grounding conductor to the CT cabinet in addition to the neutral/ground wire coming in from the utility service transformer?  In other words, for the service entrance conductors running from the metering cabinet (outside) to the main switchboard (inside), does the NEC require that a ground wire be run in the conduit along with the three phase wires and the utility neutral?  


RE: NEC Grounding Question - Grounding of CT Metering Enclosures

The code does not require an EGC for the CT cabinet, assuming that it is on the line side of the service disconnect.  The NEC permits the service grounded conductor to be used for the grounding and bonding of non-current carrying parts on the line side of the service disconnect.  250.80

RE: NEC Grounding Question - Grounding of CT Metering Enclosures

Thanks much.  I thought it was there, but just couldn't find it.


RE: NEC Grounding Question - Grounding of CT Metering Enclosures

If it is metal and could become live above ground than it needs to be grounded. common sense.
Look at all those metal enclosures they used for traffic light controls and power in toronto. The ones that were flush mount on the sidewalk are the biggest problem.Salt gets in and degrades the wires to the point where the enclosure gnd develops high impedance. This combined with hot wires touching the enclosure either because the wires broke down or the enclosure was full of salty water caused the flush mount enclosures to become live.
This killed 3 dogs in the last ten years in toronto.
I tend to think someone didnt gnd the enclosure and the salty water became live.
I am an electrician and it always dumbfounds me when I have to tell journey men to gnd that enclosure. The trade really has some scary workers.

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