Working space with raised floor

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skiddles

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Electrician
Trying to find if this is a code violation.

We have a 480V transformer being mounted in a room. It is a condition 1 installation with over 3' of free space in front of the transformer. However, in the 3' working space is a 4" concrete pad where equipment used to sit. The concrete pad is inside of the working space. Can anyone reference code that allows or disallows the transformer to be set here? Is it possible to raise the transformer 4" so it is above/level with the pad?
Thanks gentlemen.
 
There are more than just men here, and not all of us are gentlemen. ;)

I am in the group that believes a transformer does not require working space. Other members of this forum disagree. If you plan to provide working space, then the concrete pad would create a violation. Raising the transformer might work, but you would need the entire 30x36 inch working space to be on the same level.
 
charlie b said:
Raising the transformer might work, but you would need the entire 30x36 inch working space to be on the same level.
Click to expand...

Equipment requiring working space is built on housekeeping slabs all the time. Slabs that are intentionally built to be slightly larger than the equipment footprint, because of concrete construction practices. How exactly is working space supposed to be measured when housekeeping slabs get in the way?

I would expect that as long as your "refrigerator box" of required workspace can sit flush with a continuous floor between the housekeeping slab and everything else in the room, that you would be all set. By "refrigerator box", I mean the virtual rectangle that the NEC requires of working space.

As an example, the distance from the equipment front surface to the wall behind it is 40", and the NEC requires 36" of workspace. The housekeeping slab extends 4" in front of the the equipment face. The clear space on the floor is now 36",which is the workspace depth we need. Had this situation started with 36", being reduced to 32", then I could understand a violation.
 
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