Smoke Detector Wiring

[bilbo_88]

Hi All

Just a quick one. Recently had a job to install inter linked smoke detectors in the communal area of a house converted to 2 flats. Health and safety requested standard mains powered smokes with interlink.

I wired this through floors in T+E as I would in a standard domestic property, but have been pulled by another electrician stating it has to be in FP200. I have wired these from the lighting circuit (also wired in T+E) and used radio link bases so wiring it in FP200 seems pointless and pretty harsh reason to fail an EICR?

Any opinions and reg references are appreciated

 

[Ian1981]

No - C3 maybe?

I would say it's more to do with a fire alarm service report issue and not a eicr.
You could note it on the eicr in comments if there was an issue but bs 7671 don't cover fire alarms.
Bs 5839 -1
Bs 5839-6 for dwellings

 

[westward10]

FP200 not used for smoke detectors- C2

Had no regulation reference or anything

I would contact them and ask their reasons. A Grade D system does not need fire resisting cable unless the requirements of BS7671 could only be met by doing so. I find it unlikely, though not impossible the reason is for an inappropriate wiring system on an escape route. More likely they have misread BS5839-6 or confused it with BS5839-1, the fact they have given a Code 2 is neither here nor there and it would be interesting to know why they have picked up on it to resolve your problem.

 

[davesparks]

Reading that 422.2.1, towards the end it does say for BD2/3/4 the wiring systems shall be fire rated... (edit : just read Ian post #24 )
I did set fire to a cable to see what happened - not as bad as I'd hoped thought with the cable self extinguishing within about 10sec. Not surprising it failed IR testing after meeting Mr Rothenberger. Now for the pics

View attachment 36346

fire will tend to travel upwards rather than down so you have it biased towards self extinguishing there. If you did it again but set fire to the bottom of a vertical section of cable you might get it to burn a bit longer.

 

[charlie76]

An interesting read if you have 10 minutes spare.

 

[tazz]

We are going off in a tangent here..lol
Domestic fire detection must meet BS5839 part 6 & BS 7671. Grade D can be wired from the consumer unit or from a local light fitting, in normal T&E. If specified then LSOH. As with emergency lighting, the units contain back up batteries. So the cable is sacrificial. The units also require a screwdriver to remove from the base, giving total isolation from mains, complying with the lockable isolation rule. Grading such as A,B,or C utilize a central psu, or control panel so the cable now becomes and issue to supply as long as possible. So here FP or Pyro would be required.