Fire Alarm Cabling.

[Goodsparks]

Ok, here goes.
Is it possible to use a 4 core FP200 cable for both loop and sounder circuit wiring?
I would like to avoid using loop-powered sounders and a conventional sounder circuit would allow an easier interface with other devices by means of a relay, rather than an interface etc.

Have seen it done on one install but it was picked apart by another contractor. Can`t find anything specific in BS5839

System will be in a single storey primary school (ultra low risk of mechanical damage, final exit in each classroom- alternative through protected corridor)

Cheers
Paul

[Graeme]

The only example i know of but never used is the Addressable 4-wire split loop which i think you are describing and is ok.

you are limited to a loop of 2000m2 as a fault in the cable is assumed to affect every conductor.

[colin todd]

Graeme, I think he means it is ok to use a 4c for detectors and sounders (2c for each). The philosophical problem is that you double the number of junctions in your sounder cct, and you double the number of junctions in your detector cct. However, PD 6531 contains an interpretation of this in relation to BS 5839-1: 1988.

[Goodsparks]

Colin, yes that was what I was considering.

[Goodsparks]

Am I therefore correct in thinking that Sec 2.7 of PD 6531 deems it to be acceptable? (providing we utilise 2 sounder circuits through seperate cabling etc)

[colin todd]

It does point out that was nothing in BS 5839-1:1988 to prevent it. There has been no specific change in the 2002 version that would address the question. However, I always feel that it does create unnecessary junctions. Given the risk, you may feel it is ok.

[Graeme]

i have used conventional sounders on an addressable system,usually to keep costs down or high load on loop and driven them by sounder control units and outputs from panel.
I wired all as individual circuits and it was a pain,although i would not consider the 4 core method.I would imagine in theory it would be as Colin described with too many joins unless all the sounders are at the detector positions and you are using the Fulleon Squashini model for example with detector on top.4 Core is not the easiest to run as well.
Better stock up on ceramic connector block.