After we use our shower, our ceiling makes a buzzing noise (sounds like a bug stuck up there). When my husband moved the drop ceiling tiles he noticed one rail is carrying current (it was throwing off a continues spark when it touched another metal). We turned off the breaker in our apartment and the apartment above ours and it was still carrying a current, not as strong as it was before we turned the breakers off but still enough to notice. Any ideas as to what it could be? is it possible that who ever installed the drop ceiling drove a nail into a wire in the wall?
Switching just the 2 apartment's breakers off was a good try, but now you need to switch other breakers until the current is gone. Then, leave that circuit off even if someone needs to run an extension cord or 2 until the repair is completed.
Once it's gone, then nails can be extracted & reinserted until the offender is found in the ceiling & walls, the token (hopefully) long nail or screw would be the likely culprit. If the Landlord doesn't act immediately & filing a complaint with Local Officials has an estimate of weeks, months, a year or never.
Then, you can still protect yourselves by insulating the drop's grid, perimeter rail ends & bottoms & the hanging wires. Rails with, bicycle inner tube chunks, plastic L's like the clear clips that come with mini-blinds to secure the blind's bottom (stores sell them in bulk packs), or anything similar in shape & material. Hanging wires can be removed & wrapped with electrical tape & reinstalled or at the ceiling you may be able to slip on small rubber tubes.