There's No Grounding Conductor in Disconnect Switch and Circuit Breaker Enclosure

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Tainted

Senior Member
Location
New York
Occupation
Engineer
I went to the site today was tracing existing feed for a boiler panel to potentially reuse. Tracing the feed went something like this:

Service end box -> Wireway -> CT Cabinet + 600A switch combo -> 175A circuit breaker with enclosure -> 200A disconnect switch -> MLO Boiler Panel

There was no ground conductor located in and between 175A circuit breaker enclosure and 200A disconnect switch, there was no ground conductor even going downstream the 200A disconnect. Why is that? Am I missing something?
 

nickelec

Senior Member
Location
US
If the raceways are metallic it's definitely the EGC continuity would be based mostly on workmanship and if the site has hazardous locations that would deteriorate the conduit

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Tainted

Senior Member
Location
New York
Occupation
Engineer
If the raceways are metallic it's definitely the EGC continuity would be based mostly on workmanship and if the site has hazardous locations that would deteriorate the conduit

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How come a lot of the circuits and feeders I come across use conductors as an equipment ground rather than a raceway? Doesn't the metal raceway then defeat the purpose of installing conductors as equipment ground?
 

nickelec

Senior Member
Location
US
Sometimes spec would require a wire type EGC regardless of raceway material's

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Sometimes spec would require a wire type EGC regardless of raceway material's

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Yeah I wouldn't rely on conduit (maybe threaded rigid) for an EGC for a feeder that size.

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Tainted

Senior Member
Location
New York
Occupation
Engineer
Yeah I wouldn't rely on conduit (maybe threaded rigid) for an EGC for a feeder that size.

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Would it be easy to re-use existing conduit with feeders and just install new ground conductor 200' away from the main? The existing conduit is EMT. Is it hard to pull and install the ground conductors in an existing conduit?
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
How come a lot of the circuits and feeders I come across use conductors as an equipment ground rather than a raceway? Doesn't the metal raceway then defeat the purpose of installing conductors as equipment ground?
Because the Cult of the Green Wire has most of the American electrical industry in it's clutches. A properly installed metal raceway is a better equipment ground than any size wire you could stuff in it.
 

nickelec

Senior Member
Location
US
Because the Cult of the Green Wire has most of the American electrical industry in it's clutches. A properly installed metal raceway is a better equipment ground than any size wire you could stuff in it.
Agreed

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Would it be easy to re-use existing conduit with feeders and just install new ground conductor 200' away from the main? The existing conduit is EMT. Is it hard to pull and install the ground conductors in an existing conduit?
So for 175 you'd need a #8 copper. Get some simpull THHN (real slick). How big is the pipe? It can be challenging, especially with the old TWN insulation and wires all twisted up. Try a fiberglass tape first. Maybe use wire lube.

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Because the Cult of the Green Wire has most of the American electrical industry in it's clutches. A properly installed metal raceway is a better equipment ground than any size wire you could stuff in it.
I agree if it's wrench tight threaded rigid conduit. I don't consider EMT with setscrew connectors a viable EGC. Just from my own experience in years of factory work.

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ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
Would it be easy to re-use existing conduit with feeders and just install new ground conductor 200' away from the main? The existing conduit is EMT. Is it hard to pull and install the ground conductors in an existing conduit?
It would be next to impossible to add a wire to that conduit without pulling the rest of the conductors out and then back in, plus there is no need to.
 

Tainted

Senior Member
Location
New York
Occupation
Engineer
Because the Cult of the Green Wire has most of the American electrical industry in it's clutches. A properly installed metal raceway is a better equipment ground than any size wire you could stuff in it.
It's debatable. I'm considering to just put a note for contractor to verify ground continuity... Kinda feel iffy about using metal raceway as an ECG because , rarely see anybody do it, and I rarely see it.
So for 175 you'd need a #8 copper. Get some simpull THHN (real slick). How big is the pipe? It can be challenging, especially with the old TWN insulation and wires all twisted up. Try a fiberglass tape first. Maybe use wire lube.

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I think the pipe is 2" with THWN 3/0 feeders.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
I agree if it's wrench tight threaded rigid conduit. I don't consider EMT with setscrew connectors a viable EGC. Just from my own experience in years of factory work.

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I work on a lot of old electrical installations that have nothing but EMT for an equipment ground and they are fine. I'm in a building now that was built in the late sixties and there is not a green wire to be seen and everything is fine. If you were in a factory with conduit not holding together then that sounds like a problem with the environment it was in or the manner in which it was installed, secured and supported.
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
It's debatable. I'm considering to just put a note for contractor to verify ground continuity... Kinda feel iffy about using metal raceway as an ECG because I rarely do it, rarely see anybody do it, and I rarely see it.

I think the pipe is 2" with THWN 3/0 feeders.
That's doable. It's up to you what to do. This is quite a hotly debated subject here. If you can verify that the conduit is intact the whole length and you're 120v to ground, then should be fine.

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
I work on a lot of old electrical installations that have nothing but EMT for an equipment ground and they are fine. I'm in a building now that was built in the late sixties and there is not a green wire to be seen and everything is fine. If you were in a factory with conduit not holding together then that sounds like a problem with the environment it was in or the manner in which it was installed, secured and supported.
It happens man. I see it all the time. Machines vibrate, connectors separate, you lose your ground. It's just bad practice IMO.

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