Alarm ... 100m away

[danny7299]

hi all , Long time no speak ,

I have inherited an alarm system job , Panel is 100m away from house and there is a 8core cable going from the pannel to the house, the customer would like a little internal siren adding in the house so that they can hear when the barn alarm goes off,

What the best way of doing this?

Many thanks

Danut the kettle on

 

[steptoe]

what is the 8 core cable for?

 

[danny7299]

i dont know , just got told that it comes from the pannel to the house. it isnt doing anything at the mo, i know that the run is to long to put a siren on it directly , but i didnt know if that helps in any way

 

[steptoe]

how do you know that?

do you have the specs for the cable/panel/siren?

 

[kerching]

I don't do many alarms but, if the 8 core is redundant then test it to confirm no faults. Double, treble or Quad up the cores to reduce the overall resistance. Find out which uses the least power [loud speaker or sounder] then fit it. Well it seems like a plan to me... :coat

 

[danny7299]

how do you know that?do you have the specs for the cable/panel/siren?

the customer said , that cable there comes from the pannel the other bloke put it in , ( its labeled "from the alarm pannel")

no spec , just a standard 8core alarm cable (duct grade) and havnt bought a sounder yet.

pannel is just a domestic honeywell accenta

 

[steptoe]

you could maybe even use a relay.

its do-able, just needs a bit more investigation methinks.

 

[SLIPSHOD & SLAPDASH]

hi all , Long time no speak , I have inherited an alarm system job , Panel is 100m away from house and there is a 8core cable going from the pannel to the house, the customer would like a little internal siren adding in the house so that they can hear when the barn alarm goes off,

What the best way of doing this?

Many thanks

Danut the kettle on

How about an effing big siren in the barn ?

Or........ most alarm panels have an internal speaker output, use that with guess, a speaker in the house so very little current needed

 

[danny7299]

How about an effing big siren in the barn ?Or........ most alarm panels have an internal speaker output, use that with guess, a speaker in the house so very little current needed

there are 2 x master blaster in the barn , Owch ! and its all tin and concreat so echos like a cave !!

 

[Curley]

Hi,

split the eight core (once you have tested each core and core to core to ensure the insulation is good) four colours for pos and four for negative then buy an 24VAC psu (just a transformer) and a 12 to 24vac sounder the ones we use draw 60 to 80 mili amps (fire panel kit also usually will have a pot in the back to set the volume level you req).

Useing AC will take care of any voltage drop issues you would have if you went the DC route.

good luck

 

[aptsys]

Useing AC will take care of any voltage drop issues you would have if you went the DC route.good luck

Sorry, what????!

 

[Andy™]

Useing AC will take care of any voltage drop issues you would have if you went the DC route.

do explain....

 

[Bacon]

Wouldn't a repeater panel be good enough,Or as Steps had mentioned put a relay in the sounder from barn to house,sounder activates closes relay then activates alarm in house.

 

[steptoe]

DC over such a small csa will drop a lot more than AC will, remember AC is hitting 0 ever 50th of a second.

 

[Curley]

[quote name='Andy

 

[Sidewinder]

ELV kitDC voltage drop over 6 or in this case 8 core alarm cable over, (again in this case) 100m will bite you in the bum almost everytime, for alarms etc typical supply 12vdc down thin cabling you can easily end up with <9VDC (the threshold at which most alarm cctv kit will stop working) at the other end due to the current drawn by the load (sounder) and the relatively high resistance of the cable (basic Ohm's law stuff), doubling, trebling etc the cabling might do the trick (dont guess measure under load).

an AC supply in these situations cures the issue. not going to get into inductance, inductive reactance(think of as AC resistance) and the like here, simply to say that in AC circuits there are other factors of relevance other than simply the CSA.

ever wondered why we use AC transmission networks when most of the early electricity supply companies used DC.

had a weird job about 15 years ago where we ended up sending 24Vac down a 4 pair cable, rectified it back to dc to run a transmitter, still running to this day, worked out a bit cheaper than trenching over 200meters. end result a happy customer.

sean

sean,

Wrong on so many counts I can't be bothered to detail them, sorry it's late & I have been at a party.

The REASON that the national grid is a.c. is for cost reduction and the ease of voltage transformation, to minimise Joule losses end of.

 

[aptsys]

ELV kitDC voltage drop over 6 or in this case 8 core alarm cable over, (again in this case) 100m will bite you in the bum almost everytime, for alarms etc typical supply 12vdc down thin cabling you can easily end up with <9VDC (the threshold at which most alarm cctv kit will stop working) at the other end due to the current drawn by the load (sounder) and the relatively high resistance of the cable (basic Ohm's law stuff), doubling, trebling etc the cabling might do the trick (dont guess measure under load).

an AC supply in these situations cures the issue. not going to get into inductance, inductive reactance(think of as AC resistance) and the like here, simply to say that in AC circuits there are other factors of relevance other than simply the CSA.

ever wondered why we use AC transmission networks when most of the early electricity supply companies used DC.

had a weird job about 15 years ago where we ended up sending 24Vac down a 4 pair cable, rectified it back to dc to run a transmitter, still running to this day, worked out a bit cheaper than trenching over 200meters. end result a happy customer.

sean

Jesus :yellow card where did you learn your theory?

 

[alarm man]

just fit a 12 v piezo buzzer,will work fine,only pull around 30ma so will be around 0.8 drop,