Just in case you are concerned, we are not using the outlets with the problem now until a professional electrician comes to work on the room, but I wonder how this weird issue could take place.
In a room that was not used often at the workplace, the outlets (North American standard) in 3 of the walls are not working properly, or poorly. It was not a big problem as the room was not used with electrical equipment until recently.
We tested the light in the switch of a power strip, it looked dim in the 3 bad outlets, so the outlets were not used as devices did not turn on or they didn’t burst.
Now there is one wall where the outlet did work… actually, it looked like it worked, the power light in the power strip turns on brightly, computers plugged to it do work, new digital projectors work, monitors work. But if one connects a set of speakers, with or without the surge protector/power strip, to that “good” outlet, then the speakers are toasted. Same with some fans, and in an old fashion overhead projector, the bulbs burst as soon the power switch was turn on.
One possible clue is that the old over head projector’s instructions reported that the outlet should be grounded, otherwise the bulbs would burst.
This issue was not found by all at the same time, different employees and assistants found the problem intermittently and with the room not used often, it was not until recently that a connection to one likely reason (bad wiring) was made.
Still, it doesn’t explain to us why equipment with ground wire like computers continued to work, but other items with ground wire (like the old fashion overhead projector) did fail. And why other devices with no ground wire also popped and smoldered.
What could be the most likely electrical problem? Yeah, it could be bad wiring, but I have trouble imagining the logic or possible reasons why some equipment did work and others didn’t.