Safe to leave loose wire under smoke alarm?

[hashbeef]

The wired-in smoke alarm on our first floor landing started chirruping to let us know the back-up battery needed to be replaced. It's on a high ceiling above a stairwell, so can only be reached by reaching over the drop with one hand (the other hand on the ladder, held firm by me). DH only managed to detach the unit after several one-handed tries, but the white wire pulled loose. He can't re-wire it one-handed so, instead, he poked the wires up through the hole and reattached the unit with no power. We have lots of other smoke alarms, so I'm not concerned about it not working, but is it safe to leave it with the loose wire?

This pic was taken before he managed to detatch the unit.

This is mains powered but the white is probably a signal wire which connects all the alarms together.

I would push the test button on one of the other alarms to make sure they all come on and look up the manual to see the voltage of the signal wire.

In the short term it's probably touching plasterboard or insulation so unlikely to be dangerous for a fews days while you get it fixed.

I would say it is not safe - you do not know what they are are touching or sparking off. Even if it is a signal wire, I do not know if that is 6v/12v or even full 240v.

If you do not have a ladder, can you not borrow one from someone like a neighbour?
If not, call an electrician.

I wouldn’t leave a live wire expose like that.