Re-using alarm system wire for Grade 4 alarms

[Guest MrQuestion]

Hi

Went to a property today which had a very old fire alarm system installed. It's wired in 3 core flex with multiple faults. 

 

Parts are proving difficult to get for the current setup. I was thinking can Iuse the existing wire and install inter-inlinked smoke alarms ????

 

I'd disconnect the call points.

 

Thanks in advance.

 

 

[green-foam]

Assuming its a house (Interlinked smoke alarms are not suitable for commercial premisses) Then flex should not be used as it is not meant for fixed wiring. Also you may end up with more problems than you solve. It would be better to re-wire the whole thing in the correct cable.

[AnthonyB]

Grade 4? No such thing unless you mean L4

3 wire with call points sounds like an old system in a commercial building, either 240 v or 24v off a separate charger and battery box, either with a separate indicator panel, just a diversion relay, or nothing other than the mains switch. It could have been partly updated by adding a 'modern' style control panel which may by itself now be getting in age.

You can still get 3 wire compatible replacement panels and if you need detection you can run a new two wire zone for the detector heads. All new cabling will need to be fire resistant.

You can't remove call points, the base system required for premises is a manual system of call points, detection is an extra where required by the premises layout, risk and usage (e.g. sleeping risk)

You can add pictures on this forum so images of what you have (cable, call points, panel, etc) that would help.

[Tom Sutton]

Could he mean a grade D system and he/she needs to give a more detailed description of the system.