Will a magnet have an adverse effect on an alarm control box?

no. The mag field will be far too low to affect relays or sounders.

NT

Cheers

Thanks chaps. I'll sleep easy :-)

If the magnet isn't moving the the static field won't be strong enough to affect any relays.

If you are going to get problems it'll be when the magnet, and thus the field, is moving and inducing voltages/currents in nearby conductors. I wouldn't expect such induced volatges to be significant to an alarm system. Unless you have fitted a BFO neodynium magnet but that would make getting the flap off the box difficult. B-)

Interesting. At present, the magnet is attached to the flap, so does move. Perhaps I should attach the magnet to the control box.

Well, it has not been, so far. The flap raises to vertical, then perhaps another five degrees before hitting the control box. Moving either would not be trivial, hence a need to secure the flap when open. At present, just brushing against it (without the magnet in place) can be enough to bring it down. I could use a hook, but a magnet just works without intervention.

The magnet in question is part of an old toy, but does the job.

I'd guess not, as its kind of neutralised at the point its against the metal case. Brian