floor box in "maintenance area"

[malachi constant]

I recently designed a bus garage. Space adjacent to garage is a maintenance shop where they will do very light woodwork - but not classified as woodshop. Has a workbench against the wall and a table in the middle of the room. The table will hold a table saw. For this I specified a drop cord. Owner has since said they prefer a floor box, as the drop cord may get in the way of materials as they push them through the saw.

Is a floor box allowed in such a space? Two things that could prohibit it, right? The woodshop thing (which this is not classified as, so that should be OK), and being adjacent to a vehicle maintenance space. I'll have to check on the classification of this workroom space as it relates to the vehicle maintenance space, and maybe check with our HVAC design, but that could realistically be an issue. Am I missing something?

Their suggestion, if a floor box is not allowed, is to not put any power at the table, and just run a cord over from the wall whenever the table saw is in use. That's crazy, right? I mean, if the saw is not permanently mounted in place they could technically do it, but that's still crazy, right? Shouldn't they just position the saw so that the materials don't get caught in the cord?

 

[texie]

I recently designed a bus garage. Space adjacent to garage is a maintenance shop where they will do very light woodwork - but not classified as woodshop. Has a workbench against the wall and a table in the middle of the room. The table will hold a table saw. For this I specified a drop cord. Owner has since said they prefer a floor box, as the drop cord may get in the way of materials as they push them through the saw.

Is a floor box allowed in such a space? Two things that could prohibit it, right? The woodshop thing (which this is not classified as, so that should be OK), and being adjacent to a vehicle maintenance space. I'll have to check on the classification of this workroom space as it relates to the vehicle maintenance space, and maybe check with our HVAC design, but that could realistically be an issue. Am I missing something?

Their suggestion, if a floor box is not allowed, is to not put any power at the table, and just run a cord over from the wall whenever the table saw is in use. That's crazy, right? I mean, if the saw is not permanently mounted in place they could technically do it, but that's still crazy, right? Shouldn't they just position the saw so that the materials don't get caught in the cord?

I think the floor box outside of the classified area would be compliant, but I don't think it would be advisable due to survivability issues. What I have done for shops like this is rough in 1" RMC with a 90 and a coupling poured flush with the floor. On trim out, you screw a 12" nipple and FS box into the flush coupling in the floor. The nice thing is the recep is out of the dirty flush floor enviroment and if they decide it is not needed later they can just remove it and put a flush plug in the coupling that is flush with the floor. It also lends itself to configuring many types of power as needed.

 

[malachi constant]

Texie, that is a good recommendation. Need to make sure the area is unclassified before putting something at the floor though.

I dove into the code (2011 cycle) a little more and would appreciate anyone's insight. The vehicle bay is classified as a minor repair garage. It receives four air changes per hour blah blah blah as required by 511.3(D)(1)(a). So, per that subparagraph, "the entire floor area shall be unclassified".

But the area I am talking about is the workroom adjacent to the vehicle bay. This is addressed in 511.3(E)(1). "Areas adjacent to classified locations in which flammable vapors are not likely to be released, such as stock rooms [etc] shall be unclassified where mechanically ventilated at a rate of four or more air changes per hour, or designed with positive air pressure, or where effectively cut off by walls or partitions."

My question: what does "effectively cut off by walls or partitions" mean? We have a wall separating the spaces. The wall has a double and single door in it between the spaces. Is that effectively cut off, or do the presence of doors compromise it?

 

[kwired]

I think the floor box outside of the classified area would be compliant, but I don't think it would be advisable due to survivability issues. What I have done for shops like this is rough in 1" RMC with a 90 and a coupling poured flush with the floor. On trim out, you screw a 12" nipple and FS box into the flush coupling in the floor. The nice thing is the recep is out of the dirty flush floor enviroment and if they decide it is not needed later they can just remove it and put a flush plug in the coupling that is flush with the floor. It also lends itself to configuring many types of power as needed.

The only problem with this is if the raceway is supporting the box you must have 2 raceways, otherwise good suggestion. 2nd raceway could just be capped below the floor - it is only there to provide support, and of course you will need 3 piece couplings to be able to assemble it after concrete is poured.

 

[texie]

The only problem with this is if the raceway is supporting the box you must have 2 raceways, otherwise good suggestion. 2nd raceway could just be capped below the floor - it is only there to provide support, and of course you will need 3 piece couplings to be able to assemble it after concrete is poured.

Well, I knew a sharp eye here would catch this. I should have mentioned adding a bracket to make it compliant. I'll be more careful next time.