DIY Doctor UK DIY Forums

Hi, apologies if this has been covered already, I couldn't find this scenario on the forums or anywhere else.

To comply with the new Scottish smoke alarm regulations, I am replacing my old hardwired smoke detectors with battery powered interlinked smoke and heat detectors.

My question is around how to decommission/disconnect the unused supplies to the old hardwired smoke detectors. I know I'm not supposed to just cap them and put them back in the hole, but a blank plate would look weird on the ceiling, and it's impractical to rip the wires out.

Luckily our fusebox has a separate circuit for the smoke detectors. Can I just disconnect this circuit from the fusebox, and if so, how? I'm guessing it's not sufficient to just leave the circuit breaker in the off position permanently and label it accordingly?

Attached picture shows opened fusebox with the smoke detector circuit breaker marked (this is labelled clearly on the outer casing of the fusebox).



Any advice appreciated. If it's not easy to do safely I will of course just get someone in but wanted to know my options. Thanks!

I have to ask, why do you want to "Decommission" your working smoke alarms?
Scottish regulations don't say they have to be hardwired, but it does say they have to be interconnected.

If you really want to "decommission" your smoke alarms, turn off the MCB for now (Take the batteries out) and get an electrician in to disconnect it properly. The inside of a consumers unit is not something to be touched by the untrained, as it can easily KILL YOU!

Apologies if I wasn't clear. I am replacing the old hardwired smoke alarms because there are too few (per regulations I need 3 smoke + 1 heat, currently there are 2 smoke) and they are out of date anyway. I chose to replace them with a set of battery powered alarms because these are easier for me to set up and fit, rather than try to interlink new hardwired alarms with the existing system.

Therefore I do not need the supply to the old smoke detectors any more, but I believe it should be properly disconnected (have I misused the word "decommission"? Not sure why you have emphasised with quotes) so that there are not unused live wires in the ceiling. For now I have flipped the MCB switch to off but I'm not sure this is an acceptable long-term solution.

If my only safe option is to get someone in to do disconnect the old smoke detector circuit then that's fair enough, just wanted to see if it was possible to do this myself.

Anyone can only go by what they see before them, in your first post you did not say that your current smoke alarms were out of date, that is why I asked why you wanted to "Decommission" them.

My original reply to your question still stands.

Mr White wrote:......... turn off the MCB for now (Take the batteries out) and get an electrician in to disconnect it properly. The inside of a consumers unit is not something to be touched by the untrained, as it can easily KILL YOU!

You also said "

fdh wrote: disconnect this circuit from the fusebox, and if so, how?"

I for one would like to see you post again in the future, you can't do that if you kill yourself, by doing something you do not have the knowledge or training to safely work on.