Years ago I did some work in the local hospital morgue on the Access System.
From the day the system was installed they thought they had a ghost meddling with it with lots of banging, with doors locking and unlocking on their own...
Hospital Services had fitted the kit, and after some investigation I found the problem. One 2A PSU was running 3 Double mags @1A each. Obviously the doors were taking it in turn to lock and unlock. A big fat 5A PSU fixed it...
I can imagine it was quite a bit spooky! (did make me laugh though )
Worst but, apart form the guests, was the 70VAC across the Ceiling Grid and the PSU Earth. Oohh that hurts..
Hospital services didn't give a $h1t...