One of my industrial customers recently had an OSHA inspector come through and make a "recommendation" that an installation I did represents an electrical hazard.
For years I've made up buss drop cables hanging from the ceiling with Kellum grips into 4" square boxes with either twist-lock or 120V duplex receptacles for machines.
His opinion is that when plugging into such a box the employees could push in the knock outs and be exposed to an electrical shock. His argument is that the box is not intended for this use.
He can't quote a code that prohibits this, it's just his recommedation.
I think it may have to do more with the UL listing of the 1900. I have heard that the commonly made up 1900 box extension cordsets seen on every construction job are a no-no, besides the fact they typically lack the GFI protection.
How about mounting an FS box on the end of the cable?
Although I hate cord drops, I think that the idea of pushing out the KOs is weak. If that were the case, wouldn't it be a problem with the boxes mounted on the wall as well? The 4-S boxes are meant to be secured. Any of the other ways the guys have shown here are better.
I did think there was some sort of OSHA prohibition on making extention cords and the like with a 4S used on sites for temporary power. Not an NEC thing, but I think they might have something in the OSHA stuff? Anyone seen a wording for it?
Mark Heller "Well - I oughta....." -Jackie Gleason