Changing Radial and adding alarms

[kentishman]

Currently, in my airing cupboard, I have a Switched fused outlet fed direct from a 16A MCB Radial. (It used to feed an immersion heater, but the hot water is now heated indirectly by the boiler.) The outlet now feeds a shower pump (located in the airing cupboard) and is the only device on the Radial. I have a burglar alarm also situated in the airing cupboard that is currently fed from the upstairs lighting circuit, and some linked smoke alarms also fed from the upstairs lighting circuit.

So.... my question. I am thinking of extending the Radial to two additional switched fuse outlets adjacent to the existing one, and wiring the burglar and smoke alarms to these. The pump is rated 550 Watts, so a 5 Amp Fuse would presumably suffice, and similarly 5 Amps would be sufficient for each of the alarms. The additional fused outlets would be surface mounted adjacent to the existing one, with the cables feeding the alarms in surface mounted trunking (as it's not going to be seen). I was thinking of using 1.0mm cable for the feeds to the alarms (as I have plenty of this already), and 2.5mm for linking the fused outlets. Is this ok? The airing cupboard is on the landing, so am I right in thinking notification under part P should not be required, and that I can complete this work on my own? Ideally, the alarms should be on their own circuit(s), but I thought this would be an easy way to get them off the lighting circuit which occasionally trips when a GU10 lamp blows.

Thanks for reading this, and for any advice you may give.

 

[Spark123]

The big advantage of having the smoke detectors on your lighting circuit is that you do notice when the supply trips.
If you move them to another circuit and it trips then you may not know about it.

 

[kentishman]

Thanks for your reply, Sparky.

Good point. I was going to use switched fused outlets with neons to give some indication. I suppose it is a toss-up between having the alarms on a circuit that has a (slightly) higher risk of tripping, but with an indication that it has tripped, or having them on a circuit that is unlikely to trip, but has only a hidden indicator that it has tripped. The smoke alarms do make a slight bleeping noise when the power is off though.