Is it permitted to install an outlet above a drop ceiling grid in a commercial or residential occupancy?

No, but if you install a receptacle outlet above a drop ceiling you can't really plug anything into it because cords can't be concealed in a ceiling.
 
Just as a practical matter, and I know this doesn't have any basis in the NEC, but in Seattle we often have cord and plug HRV's above drop ceilings, and the inspectors allow us to put that split loom wire covering stuff over the cord.
 
Just as a practical matter, and I know this doesn't have any basis in the NEC, but in Seattle we often have cord and plug HRV's above drop ceilings, and the inspectors allow us to put that split loom wire covering stuff over the cord.
What’s an HRV?

Anyway, that’s a double whammy. Plug in a receptacle above ceiling and covering a flexible cord.

-Hal
 
Does anyone manufacture a cable product that is dual rated as both an article 400 flexible cord and an article 300 wiring method? Would such a dual rated cable be allowed concealed in a wall or behind a dropped ceiling?
 
The prohibition of using flexible cordage for building wire is because it is not designed with the longevity to last for decades and deterioration and damage cannot be detected when it is concealed. We all know how cords crack and become brittle over time. I just had to replace the cord on my Milwaukee right angle drill because the jacket was gone in places.
Does anyone manufacture a cable product that is dual rated as both an article 400 flexible cord and an article 300 wiring method? Would such a dual rated cable be allowed concealed in a wall or behind a dropped ceiling?
This situation comes up all the time when installing TVs on walls. You can’t drop the line cord down the wall or fish an extension cord up to it. They make a kit with a receptacle and box, a length of NM and another box with an inlet. Install the receptacle behind the TV and the inlet near an existing receptacle. Connect with a short extension cord.

The closest thing to a “dual rated” cable would be TC but i don’t think it’s approved for that use.

-Hal
 
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