NEC 110.26(A) condition 2

[Isaiah]

On the platform, they installed two, 3-phase 480V, disconnect switches directly across from the handrail at exactly 36" from the front of the switch. Assuming the handrail represents 'grounded parts' (condition 2) the requirement is 3'-6" of minimum clearance.
I don't believe raising the switches above the handrail would work since they'd still fall within the 6.5 feet 'Height of Working Space'.

Can the handrail be 'effectively insulated' and call it condition 1? If so, what kind of insulation would be acceptable?

 

[infinity]

I would like to hear what others say but is a handrail really grounded?

 

[Dale001289]

I n my experience I would have to say “yes”, it’s grounded since it’s probably connected to the skid and the skid is most likely bonded to the ground grid.


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[infinity]

I would have to say “yes”, it’s grounded since it’s connected to the skid and the skid is bonded to the ground grid using #4/0 bare copper conductor

Then I agree with your initial assessment something needs to be moved to get the requisite 42" of working space clearance or the grounded handrail needs to be "ungrounded" by some means.

 

[Carultch]

On the platform, they installed two, 3-phase 480V, disconnect switches directly across from the handrail at exactly 36" from the front of the switch. Assuming the handrail represents 'grounded parts' (condition 2) the requirement is 3'-6" of minimum clearance.
I don't believe raising the switches above the handrail would work since they'd still fall within the 6.5 feet 'Height of Working Space'.

Can the handrail be 'effectively insulated' and call it condition 1? If so, what kind of insulation would be acceptable?

Condition 1 means that the obstacle opposite the equipment is electrically insulating. Like a fiberglass fence or a wall surface of either drywall or plywood. To make it condition 1, the whole guardrail system would have to be covered in an insulator, such as plastic, wood, or rubber. Isolating a conductive structure from building steel doesn't make it condition 1, and wouldn't be permitted anyway. Any metal/concrete not intended to carry current is required to be grounded, if it is likely to become energized.

Elevating the switches so they aren't directly across from the handrail, would still require condition 2 working space. Imagine a "refrigerator box" of the dimensions they give you. That "refrigerator box" has to fit between the equipment and any obstacles in its vicinity, unless the NEC otherwise makes an exception.

 

[Isaiah]

Condition 1 means that the obstacle opposite the equipment is electrically insulating. Like a fiberglass fence or a wall surface of either drywall or plywood. To make it condition 1, the whole guardrail system would have to be covered in an insulator, such as plastic, wood, or rubber. Isolating a conductive structure from building steel doesn't make it condition 1, and wouldn't be permitted anyway. Any metal/concrete not intended to carry current is required to be grounded, if it is likely to become energized.

Elevating the switches so they aren't directly across from the handrail, would still require condition 2 working space. Imagine a "refrigerator box" of the dimensions they give you. That "refrigerator box" has to fit between the equipment and any obstacles in its vicinity, unless the NEC otherwise makes an exception.

Why would the whole guardrail system require insulation? Why not just insulate the working space area per 110.26? The guardrail has two tiers and extends for at least 12 feet past the switches.

 

[infinity]

Why would the whole guardrail system require insulation? Why not just insulate the working space area per 110.26? The guardrail has two tiers and extends for at least 12 feet past the switches.

I was wondering the same thing. The portion that is not in the working space wouldn't require to be insulated.

 

[LarryFine]

Would a couple of coats of truck-bed liner be suitable?

 

[Carultch]

I was wondering the same thing. The portion that is not in the working space wouldn't require to be insulated.

To clarify what I meant, I meant the vertical members in addition to the horizontal members, on the side facing the energized equipment. I don't know the details of what this guardrail might look like, but you most likely would need the insulating cladding to surround each member, so it is secured to the guardrail. You might technically only need it on the side facing the electrical equipment, but you'd most likely surround the railings.

Indeed, if the electrical equipment is only 10 ft long, and the guardrail extends for 30 ft, the 20 ft that is out of the picture can remain they way it is originally built. Only that which is directly behind the equipment for the requisite work space width, would need to be insulated to call it Condition 1.

 

[kwired]

I would like to hear what others say but is a handrail really grounded?

I n my experience I would have to say “yes”, it’s grounded since it’s probably connected to the skid and the skid is most likely bonded to the ground grid.


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I agree that in many cases it likely is bonded to grounding grid even if not a direct connection to a grounding conductor.

If it is effectively isolated from ground potential then I don't think that condition 2 applies to it. Say it were a metal rail but was supported by non conductive materials and not within close proximity to anything that might make it become ground potential. Might still be wise to insulate it in the working space area, but don't see it being required either.

 

[Isaiah]

The galvanized steel rails are in fact grounded since they’re in contact with the platform which is bolted to the equipment frame. The frame contains a large MV motor and associated instruments.
The entire assembly is grounded to the electrode system consisting of buried #4/0 bare copper conductor tied to series of ground rods. Thanks to all for this feedback


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