Sup panel troubleshoot

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PowerdT

Senior Member
Location
San Diego
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Electrical Engineer
I have an old 120/208V 3 phase panel with 4 wire and no ground, the conduit is used as a ground.

when I open the panel I saw some of the branch circuit terminated on the neutral bar.

I am afraid this is proper installation however one of electrician said its normal?

When u measure the neutral and ground, is it normal to get continuity?
 
What do you mean by branch circuits terminated on the neutral bar? Do you have any photo's?
 
Does ground mean Equipment Ground?
or
Does ground mean Grounding Electrode?

Sounds like you mean the conduit serves as an EG.

The neutral bar should be isolated from the enclosure. No EG should be landed on the Neutral bar.

You should get continuity from neutral to EG because they will be bonded together at the Service Entrance. No where else.

Separate buildings and an old installation may have allowed the bond of Neutral to the enclosure at the Service Disconnect for a separate building.
In that case you would be required to have a Grounding Electrode System at that building.
 
ptonsparky said:
Does ground mean Equipment Ground?
or
Does ground mean Grounding Electrode?

Sounds like you mean the conduit serves as an EG.

The neutral bar should be isolated from the enclosure. No EG should be landed on the Neutral bar.

You should get continuity from neutral to EG because they will be bonded together at the Service Entrance. No where else.

Separate buildings and an old installation may have allowed the bond of Neutral to the enclosure at the Service Disconnect for a separate building.
In that case you would be required to have a Grounding Electrode System at that building.
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Yes I meant EGC. the neutral has to be isolated from the panel enclosure.

Thank you.
 
Only if it's a service panel or an old installation on a detached structure with no EGC with the feede and your metallic conduit rules that out.
 
If this is a sub panel then you are correct that neutrals and equipment grounding conductor's must be separated.
 
augie47 said:
Only if it's a service panel or an old installation on a detached structure with no EGC with the feede and your metallic conduit rules that out.
Click to expand...
It’s old panel with no feeder EGC, and it’s not on detached structure. Commercial building
 
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