Performed NEV test today. Everything tested okay until I came to an outdoor air compressor. The shielded flexible conduit comes out of the building across a fence into a disconnect and then the compressor. The compressor and disconnect switch tested fine but I found the fence to be unbonded. I thought this was strange since the feed goes right over the fence. And you must open the gate to get to the compressor. Lastly the ground is always damp in that area. So my question is, where can I read more about this in the NEC? Does this sound like a code violation? I'm guessing the fence should be bonded? Thanks
Is this safe?
- Thread starter jfalbo
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NEV?
What is the secondary voltage?
What is the secondary voltage?
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There is nothing in the NEC that would require the fence to be bonded.
Anything not connected to the electrical bonding system and connected to the earth will show this voltage. Do you want to bond every conductive object that is in contact with the earth?
Other than around pools, the few volts of Neutral to Earth voltage are not a hazard.
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Neutral to Earth voltage.
Typically represents the voltage drop on the primary utility grounded neutral. The primary and secondary neutrals are connected together and the secondary neutral is connected to earth at the service.
If you connect to anything that is bonded to the electrical system and measure voltage to "remote earth" you are measuring the NEC. Typically "remote earth" is defined as earth outside the influence of any grounding electrode and sometimes specified as being 50' away from any such electrode. Often a long screwdriver pushed into the ground is used as the remote earth electrode.
IEEE standard 80 speaks to bonding fences. It is standard practice to bind them around substations. As floating objects and fairly large conductors it is fairly easy to energize them in a substation environment.
However you are describing a metal conduit touching or passing near a fence. The shielding (bonding) of the conduit isolates it. About all you get at that point is a stray voltage with.no appreciable current even if it is measureable.
Stray voltages exist everywhere. Stray currents are the issue though, not voltages. I don’t see any point in doing a NEV test. Might as well be used on a ghost hunters show because that’s all you will be chasing.
However you are describing a metal conduit touching or passing near a fence. The shielding (bonding) of the conduit isolates it. About all you get at that point is a stray voltage with.no appreciable current even if it is measureable.
Stray voltages exist everywhere. Stray currents are the issue though, not voltages. I don’t see any point in doing a NEV test. Might as well be used on a ghost hunters show because that’s all you will be chasing.
romex jockey
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TN-S vs. TN-C-S ??
~RJ~
~RJ~
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I would clarify this to be around substations 'containing open air equipment'. It can be difficult, as well as non-cost effective, to apply IEEE 80 to an industrial substation containing only metal-enclosed equipment.
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