Connecting linked fire alarms

Hi, I have installed two interlinked fire alarms as part of a renovation project. However they are not linked at present just have two white cables, coming from each one. Is it ok to take a single core out of some 1mm/1.5mm2 cable I have laying around as I cant seem to find a single core that's not red or black, and I have three way cable with a different colour core which I could use.

Thanks John

Reply to
John Borman
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Do you mean smoke alarms, interlinked to each other? Fire alarms are as used in commercial buildings with a central panel monitoring? If so suggest you d/load one of installers manual to give you general guidance

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"alarm features/manuals" on top navigation bar You can only interconnect with 3 core & earth. These manuals are for UK market only.

Reply to
barclayhomes

Use this link, and navigate to Manuals page

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Reply to
barclayhomes

Reply to
John Borman

Just run the whole cable and only use one of the cores. If you want you can sleave the wire at each end with a "thrid" colour to indicate it is not an ordinary mains connection.

(With my ones, I ran power from the CU to the first, and then three core and earth from there to each of the others. That way you get the power and the link delivered to each alarm in a single cable.

Reply to
John Rumm

Reply to
John Borman

If you can supply them separately from other appliances, then all the better, but convenience may dictate a supply from the lighting circuit. If it's a huge job to run a supply directly back to the consumer unit, then tapping into a nearby lighting junction box would be OK. But it is better to run a separate constant, uninterrupted supply to them.

Reply to
BigWallop

Best practice is to tap off local lighting circuit as if on dedicated circuit [which AC only alarms have to be] is a chance that if alarms play up, householder may switch off that circuit breaker. If lighting is off they'd pretty soon notice.

Reply to
barclayhomes

No. I'd use the entire cable and ignore unused conductors, or relay with 3 core+E. I wouldn't want to run a single cable, except in conduit, as it only has a single layer of insulation.

Christian.

Reply to
Christian McArdle

cheers for that what I may consider doing is connecting the upstairs one to the lighting circuit up there then using 3core +E to connect this one to the one downstairs gonna have a fun day tomoz. Also, (I know I will prolly be condemned for asking this, or just told to get an leccy in) after rewiring the lighting circuit using the loop in system I am stumped by a two gang two way set up. This is the situation, downstairs has a 2 gang light switch with one switch operating one down stairs, and the other one operating two lights upstairs. Ok the wiring isn't that much of a problem, I have two lots of 3C+E running from the switch down stairs to the switch upstairs. Downstairs the light switch has the approp switch cable for the downstairs light. Upstairs its has the two 3C+E cables plus the switch cable from upstairs (Actually it has two switch cable for the two upstairs lights as it was originally a 3 Gang switch and I'm changing it to a 2 Gang one)

Reply to
John Borman

If the alarms are being fitted under requirement of building regs (say because they are required as a result of the addition of a third storey to the building - i.e. loft conversion), then they must be on their own circuit, and they must also have a battery backup (which means you can't simply flip a breaker to turn them off anyway).

In a normal domestic two storey house, you can get away with using a lighting circuit for power, although this can also introduce a risk if you have separate lighting circuits for both up and downstairs, since your fire alarms would then need to be powered from only one circuit or the other (not both) to gurantee they work in unison, and also do not bridge the two circuits.

Reply to
John Rumm

Probably... but if you took the switch off you could soon test it with a multimeter (or torch bulb and battery) to make sure. The COM postion (whichever it is) will be connected to one contact with the switch in one position, and the other when you throw the switch.

Not sure there is actually a standardised way of choosing which colour gets used where. Personally I use the red for the COM connection. (You ought to always sleave the others with red since they are all lives).

Sounds right assuming L3 is COM.

Reply to
John Rumm

"John Rumm" wrote | If the alarms are being fitted under requirement of building regs (say | because they are required as a result of the addition of a third storey | to the building - i.e. loft conversion), then they must be on their own | circuit, and they must also have a battery backup ^^^

s/and/or

Very important :-)

Owain

Reply to
Owain

Well spotted! I over egged the regulations a tad there....

Reply to
John Rumm

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