4 Core & Earth Cable

[L200]

Boys ,

Excluding Gent (and maybe some other panels) under 5839 2002 is it still permissible to wire devices off the loop in 1 x 4 core , and what is he position where a 4 core is used say if someone has used conventional sounder circuit , so pair for loop , pair for bell circuit.

[stevemiddleton]

Boys ,

Excluding Gent (and maybe some other panels) under 5839 2002 is it still permissible to wire devices off the loop in 1 x 4 core , and what is he position where a 4 core is used say if someone has used conventional sounder circuit , so pair for loop , pair for bell circuit.

Most panel manufacturers advise not to use 4 core to add a device to the loop as it can cause interference, also if the cable is broken there is a higher chance of loosing the device.

Regards to 2 cores for sounder and 2 for loop I think this is OK as long as there are still 2 sounder circuits in use to meet BS5839 basics, however if you are going to do this why not just use addresable sounders for better fault monitoring anyway, surely the additional cost of the sounders would not make a great deal of difference to the cost of 4 core cable.

[L200]

I was thinking bells on conventional circuits , as most hospitals we come across still have them.

So is there any thing in BS regarding the 4 core , where I was coming from is the odd detector in 4 core not the whole job.

Thanks Steve , for posting

[TSS]

Clause 12.1

care needs to be taken in the use of multicore cables for the wiring of more than one circuit. It needs to be assumed that any fault that affects a multicore cable affects all conductors in the cable; this precludes the use of multi core cables for certain applications in which the failure of more than one circuit could result from a single fault.

thus if you run bells and detection circuits, or an out & back spur down the same cable it probably won't comply.

Also Hospitals have additional requirements I think it's HTM82

my understanding - hope this helps

[Guest Thunderfingers]

Clause 12.1

care needs to be taken in the use of multicore cables for the wiring of more than one circuit. It needs to be assumed that any fault that affects a multicore cable affects all conductors in the cable; this precludes the use of multi core cables for certain applications in which the failure of more than one circuit could result from a single fault.

thus if you run bells and detection circuits, or an out & back spur down the same cable it probably won't comply.

Also Hospitals have additional requirements I think it's HTM82

my understanding - hope this helps

This is another example of (IMO) lack of clarity between two paragraphs.

12.2.2 System integrity

The following recommendations are applicable.

a) A fault on one circuit containing manual call points, fire detectors or fire alarm devices, or a

combination of them, should not affect any other circuit.

If it is assumed that your four core is in effect one circuit then if it is damaged it does not effect any other circuit.

B) Any fault forming a cross-connection between a detector circuit and a sounder circuit should not affect

any circuits other than the two circuits involved.

Again,in this case if you treat the four core as two circuits (one of detection and the other sounders) then the fault will not effect any other circuits than the two involved.

[TSS]

is it not non-compliant if one fault affects more than one circuit?

are bells and detection considered two circuits?

looking for clarification on this one?

[Guest Thunderfingers]

is it not non-compliant if one fault affects more than one circuit?

are bells and detection considered two circuits?

looking for clarification on this one?

Had another gander at it and each pair in a multicore is a circuit (ie - one detection and one sounder in a four core for example) as they leave and terminate in individual circuits.

If you get a break in the 4 core you have lost both circuits BUT the fault on each circuit is independant of the other in this case (ie - there is a break on both circuits which does not effect the other).

So from this you could bring B into play in that it doesn't effect any other circuits other than the two involved.

[Truss and France]

We have on several occassions installed new systems using a four core cable, pair for sounders and a pair for the zone and we have never been pulled on it.

Kev

[stevemiddleton]

CAN I THROW 2 WIRE CONVENTIONAL IN TO THE EQUATION, HOW IS USING A FOUR CORE DIFFERENT FROM A 2 WIRE, EXCEPT HOW THE PANEL SEES THE FAULT.

[Guest G.J.M]

4 core for sounder and detection circuit is okay but i personally would never go down that route.

p.s steve DROP THE CAPS PLEASE.... thanks