| We renovating a section of our factory in Southern New York state, and about | to recondition a number of our old ovens and other equipment from that area | that have a variety of old twist lock plugs of various designs. I am | considering having them changed to regular straight blade 6-15 and 6-20 | plugs, but I am wondering if there is some NEC or OSHA requirements for | twist lock plugs on certain equipment.
There can be such requirements. You have to consult with appropriate experts or authority to determine. But basically, the intent for the twist-lock plugs is to prevent inadvertent disconnection of power.
I do know of one business that got fed up with its janitors unplugging computers and other equipment to power the vacuum cleaners and floor sweepers. So they had twist-lock plugs put on the machines the janitors use (sold it to them saying they wouldn't fall out so easily) and put in sufficient twist-lock receptacles for the janitors to use.
I wonder if there are any cases where straight blade is safer because of the ability to pull the plug easier in a panic, such as when the floor waxer is climbing the walls.