Yes these are rooftop units.. I just happen to wander up there when BOTH of the units cooling the floor I am working on stopped working ( Carrier units: JUNK IMHO).
All the other units up there have the discos tagged right to the sides of the units.
I am not sure how that switch got there.. I assume from the electrical the same hack did the referigeration as well and probably the original install, as the units on the floor above us have done nothing but leak onto our floor because all the condensate drains have been done improperly according to the NEW service Techs.