fire alarm supply

[moose man]

;hi all can i use a dp fused with a fish key for the spur

and does the supply have to be fire proof for the supply

or basic cable mechanical protected i have look in bs7671 can not see anythink on this

thanks moose

 

[Andy™]

iirc, supply must be fire rated

 

[Sidewinder]

Indulge me please (as usual!)

Emergency lighting.

2 scanarios.

1.

Self contained independent emergency luminaires wired from main lighting supply circuit in independent runs.

Main lighting surface T&E.

Emergency lighting FP200.

Fire happens, compromises supply to main lighting as it is not fire resistant.

Main lights fail, CB does not.

EM lighting FP200 is not compromised, emergency lighting does not illuminate, all occupants burn to death as they could not find their way out.

What cabling should you have used?

2.

Central emergency lighting supply.

Main lighting wired in T&E, emergency lighting central supply wired in T&E.

Fire starts and compromises both T&E supplies.

Emergency lighting does not illuminate, all occupants burn to death as they could not find their way out.

What cabling should you have used?

Sorry please remember this is light hearted but meant to promote thought and discussion!

:slap

 

[switch10]

well im afraid to say i would disagree with emergency lighting needing to be run in fire proof cable, been installing them along with fire alarm systems for over13 years. and normal t+e has been used.

also t+e is allways used forthe fire alarm supply.

 

[Andy™]

the main purpose of emergency lighting is to show an exit route. in example 1 above, the exit lights would normally have an emergency light thats lit at all times. all other lights are there to light the place incase of power failure. not incase of fire. so example doesnt have any major design flaws.

in example 2, central battery systems should be wired in fire rated cable

 

[Sidewinder]

Andy,

Not always maintained lighting, NM is also fine, (designation now changed, but we all know NM3!)

Same applies though and your response IMHO is spot on!

 

[mark1]

Have never had to use fire rated cable ie FP200 for emergency lighting. Yeah all fire alarm systems should be run in fire rated cable and I have always had to install key operated isolators/spurs for FA panels which also need to be supplied using fire rated cable.

 

[Sidewinder]

mark1,

Central battery systems for EM should be in FP200 or the like else how can you ensure that the luminaires will have supply in the event of a fire burning through the "T&E"?

 

[moose man]

[quote name='Andy

 

[batty]

well im afraid to say i would disagree with emergency lighting needing to be run in fire proof cable, been installing them along with fire alarm systems for over13 years. and normal t+e has been used.also t+e is allways used forthe fire alarm supply.

You should not be using tw/e for fire alarm supply that should be fire rated.

 

[Sidewinder]

Sorry guys I read the OP as EM, NOT fire alarm!

The supply wiring requirements if not in 7671 will be in the fire alarm regs, not to hand & I can't remember the no now! Too much going on in the house at the moment!

New kitten!

 

[a1spark]

;hi all can i use a dp fused with a fish key for the spur yesand does the supply have to be fire proof for the supply protected from fire

or basic cable mechanical protected i have look in bs7671 can not see anythink on this . I think T& E would be acceptable if enclosed in mettallic conduit, or completely buried in non combustible elements of the buiding, although Fp200 rype and MICC are most common methods of wiring.

thanks moose

Fire Alarms regs : BS 5839 Pts 1-6

Emergency Lighting Regs : BS 5266

BS 7671 . just for the installation method in general with regards to the rest of the installation.

a1spark.

 

[mark1]

Sidewinder. Yeah your right as a central battery system. Was thinking more towards your first scenario with the self contained fittings?

 

[Andy™]

thanks andy but were does it say it in the regs or is it in the fire regs

i think its in the fire alarm regs

 

[Lee321]

supply or detection need not be fire rated

the only requirement is for sounder circuits

 

[Andy™]

[quote name='Lee

 

[Lee321]

if they are then yes

yep loop powered sounders very common now

 

[a1spark]

[quote name='Lee

 

[kme]

I wouldn`t - depending on the system being installed, of course.

i.e. We`ve been installing in the communal area of flats. DNO supply one overhead cable, split into 4 HEDs; each feeding a meter in the communal hallway. The meters feed KMFs, then out to the flats in tails.

One flat has the tails "henley`d", and a split to a communal supply. Main switch, and RCBo`s for communal socket, lighting / em lighting, and smokies.

The smokes have a local "hush / test / locate" switch, using the same "noburn" 4 core as the detector cct. the two lengths are taken into the DB, and split to provide power at that point. No spur or other form of isolation provided / necessary. System is grade "C", cat L3.

The EM is in with the communal lighting, via a 3+E, using NM3s.

To look at Sidewinder`s post; the scenarios have the back-ar5ewards cabling - fire rated for CBUs, and "standard" for self-contained.