Conduit bonding to tray

[Isaiah]

If we have a myers hub on the disconnect switch and the conduit is attached to a cable tray does the conduit need to be bonded to the tray?


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[jaggedben]

What else is the tray bonded to?
What else is the disconnect bonded to?

 

[Isaiah]

What else is the tray bonded to?
What else is the disconnect bonded to?

The disconnect is affixed to building steel column which is bonded to the electrode system. The tray is bonded at both ends to the building steel which is contiguous throughout
The circuit contains an EGC

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[Dale001289]

The disconnect is affixed to building steel column which is bonded to the electrode system. The tray is bonded at both ends to the building steel which is contiguous throughout
The circuit contains an EGC

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Conduit is bonded to enclosure via the hub and EGC is bonded to the enclosure. The fault path is sufficient so no additional bonding is required


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[david]

If we have a myers hub on the disconnect switch and the conduit is attached to a cable tray does the conduit need to be bonded to the tray?


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292.18 (G) supported from cable tray systems
"For raceways terminating at the tray a listed cable tray clamp or adapter shall be used"

292.60 grounding and bonding when cable trays are used as an equipment ground

 

[Isaiah]

292.18 (G) supported from cable tray systems
"For raceways terminating at the tray a listed cable tray clamp or adapter shall be used"

292.60 grounding and bonding when cable trays are used as an equipment ground

Can they use a bonding jumper to the tray in lieu of clamp?


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[jaggedben]

392.60 covers using trays for mechanical support in industrial facilities. If the conduit is otherwise supported to the building like normal then you don't need the clamp.

 

[david]

The disconnect is affixed to building steel column which is bonded to the electrode system. The tray is bonded at both ends to the building steel which is contiguous throughout
The circuit contains an EGC

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250.121 (B) The structural metal frame of a building or structure shall not be used as an equipment grounding conductor.

If we have a myers hub on the disconnect switch and the conduit is attached to a cable tray does the conduit need to be bonded to the tray?


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You need an effective fault clearing path for the metal tray
A correct size bonding jumper to the metal raceway would create that path

 

[Isaiah]

250.121 (B) The structural metal frame of a building or structure shall not be used as an equipment grounding conductor.


You need an effective fault clearing path for the metal tray
A correct size bonding jumper to the metal raceway would create that path

As stated the circuit already has an EGC. The tray is bonded per NEMA VE2. An bonded to the steel which is bonded to an electrode


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[david]

As stated the circuit already has an EGC. The tray is bonded per NEMA VE2. An bonded to the steel which is bonded to an electrode


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By the information provided , we do not know where or if the tray is bonded to an equipment ground.

Nor do we know the wiring method or application, is it industrial, commercial .

We don't know the details.

The circuit having an equipment ground does not state that the tray is bonded to the circuits equipment ground

 

[Dsg319]

If we have a myers hub on the disconnect switch and the conduit is attached to a cable tray does the conduit need to be bonded to the tray?


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You working in the natural gas/oil industry? They often go far beyond NEC with bonding/grounding.

 

[Isaiah]

You working in the natural gas/oil industry? They often go far beyond NEC with bonding/grounding.

This plant is located in a non classified area.


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[Dsg319]

This plant is located in a non classified area.


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They most likely have a spec/standard that supersedes the NEC minimum you will have to follow if supplied with plans.

I know the places I work we typically just use a bind bushing at the trey. And also bond with grounding type myer hubs at enclosures.

 

[Isaiah]

They most likely have a spec/standard that supersedes the NEC minimum you will have to follow if supplied with plans.

I know the places I work we typically just use a bind bushing at the trey. And also bond with grounding type myer hubs at enclosures.

I agree. But this job is different-here the NEC supersedes the job specifications. I believe bonding to tray is desirable but not necessarily required.


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[Dsg319]

I agree. But this job is different-here the NEC supersedes the job specifications. I believe bonding to tray is desirable but not necessarily required.


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Gotcha. Is the tray connected to the grounding grid anywhere?

 

[Isaiah]

Gotcha. Is the tray connected to the grounding grid anywhere?

Yes the tray is connected to the building steel column with is bonded directly to a bare copper 500kCMIL underground equipotential grid


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[david]

Yes the tray is connected to the building steel column with is bonded directly to a bare copper 500kCMIL underground equipotential grid


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Do you know of an exception that would allow the grounding electrode system to be used instead of an equipment ground.

A 3/0 bonding ring run throught a facility bonded to every metal columb tied to the rebar that supports the columbs can't take the place of a required equipment ground for feeders and branch circuits

If your using the tray itsself as a code compliant equipment ground you haven't said so.

 

[david]

When you have a wire type equipment ground run with your branch circuit/feeder in a conduit type raceway
The wire equipment ground and the metal raceway are bonded together providing a parallel fault clearing path

 

[Isaiah]

Do you know of an exception that would allow the grounding electrode system to be used instead of an equipment ground.

A 3/0 bonding ring run throught a facility bonded to every metal columb tied to the rebar that supports the columbs can't take the place of a required equipment ground for feeders and branch circuits

If your using the tray itsself as a code compliant equipment ground you haven't said so.

I’m not sure why/how you keep coming up with using the tray as a fault path. It has nothing to do with subject matter of bonding conduit to tray. Also I never suggested using the grid or electrode system as a fault path


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[david]

I’m not sure why/how you keep coming up with using the tray as a fault path. It has nothing to do with subject matter of bonding conduit to tray. Also I never suggested using the grid or electrode system as a fault path


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I'm not saying to use the tray as a effective fault clearing path. I'm saying the tray has to be bonded to an effective fault clearing path. (An equipment ground)

250.86 not 250.96