Fire alarm feed

tazz · Apr 26, 2012

Bs5839 changed in 2002, Mains feed to fire alarm panels must be wired in enhanced fire proof cable, this can be enhanced fp200 or piro. Mains feed can be off db now or essential supply db. A lockable double pole switched fused spur must used to feed the control panel located near by. Usual 17th regs apply to cabling such as protection by rbo/rcd etc where the control panel must have battery backup and warning incase of mains failure. A lot better than the old days of comming straight off the incoming with a BS88 fuse

hillbillie · Apr 26, 2012

I flagged up a non compliant fire alarm power supply in a PIR I did last year. The power to the fire alarm board came from a bit of 1.5mm wrapped around a screw on the blue phase busbar in a TP&N d/b! The busbar was fused at 200A if I remember correctly!

I replaced the supply cable with fp200 and took it back to a d/b in the switch room, thinking that I should ensure as much of the supply circuit as possible had added fire protection. I also used a metal enclosure and a porcelain jb to connect it to the fp200 the fire alarm company had put in place.

I saw the technicians from the fire alarm company the firm used and pointed out the problem and they just shrugged their shoulders and said they just connected it up to what was already there.

supasparxs · Apr 26, 2012

hmmmmmmmmmmm

some thing never surprise me

tazz · Apr 26, 2012

Hillbillie, can well believe some of the installations, seen them so many times. But this proves a good point were both BS standards do run together, and even before the days of rcds and rbos. The installation was fused as near to the incoming as possible, and correctly fused at the rate for the cable used.

Personally we always insist on a niciee contractor to supply all power to our fused spurs with full testing certs, as with any circuit

Charlieelec · Nov 15, 2012

The Majority of fire alarm engineers (istall and service) are not qualified sparks and such all companies that i know have it in there t&c's that the customer is to supply a spur (this now should be a double pole secret key fuze)

For the company that i work for any alterations to the mains needs a Zs reading to prove safe, this was done with the niceic.

and all feeds need to be dedicated from fuze board and now run in fire rated cable. Replacement does not need to be but spur should be replaced.

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The Majority of fire alarm engineers (istall and service) are not qualified sparks and such all companies that i know have it in there t&c's that the customer is to supply a spur (this now should be a double pole secret key fuze)

For the company that i work for any alterations to the mains needs a Zs reading to prove safe, this was done with the niceic.

and all feeds need to be dedicated from fuze board and now run in fire rated cable. Replacement does not need to be but spur should be replaced.

jaresquire · Nov 17, 2012

Section 26.2 of BS5839-1:2002 with A2:2008 gives the recommendations for cabling. Generally standard fire resisting cables should be used for the mains supply, with enhanced required in some circumstances.
On the large commercial sites I attend a separate supply is made straight from the busbar, but quite often is still wired in singles from there !