Linking two fire alarm panels

[Wiz]

very true Wiz,just thinking that if the customer was a tight ar5e.

g

Understood mate.
However this whole scenario is all just an example of when and where a spur off an addressable system might have to be used, and not just because someone couldn't be bothered to form a loop. Such spurs are not disallowed by BS5839 and using them doesn't necessarily make any one incompetent or a cowboy.
Yee Haa!!

[Allen Higginson]

dum - da - da- dum -da - da - dum -da - da - dum -da - da--da!

[Allen Higginson]

Off topic I know - how many addressable spurs can you put on a loop??Customer wants to upgrade around 12 conventional zones (circa 14 devices/zone) to addressable using existing wiring (future rocky so wants to bring it up as best they can).I have only done it in large computer rooms where there has previously been a 4 + 2 conventional.

[Graeme]

Puting in systems for the stars now Buz?
 
Sylvester Stallone's son?

[Wiz]

Off topic I know - how many addressable spurs can you put on a loop??Customer wants to upgrade around 12 conventional zones (circa 14 devices/zone) to addressable using existing wiring (future rocky so wants to bring it up as best they can).I have only done it in large computer rooms where there has previously been a 4 + 2 conventional.

Technically, you could in theory have as many spurs or tees as you wanted. As long as there was a pair of wires going to each addressable device it would work! Obviously the cables would have to suitable electrically etc.
For BS 5839 part 1 2002 you would have to consider the effect that any wiring fault would have on the overall system. A single wiring fault shouldn't affect the protection in more than 2000m2 and two simulutaneous faults shouldn't affect the protection in more than 10,000m2.
Short-circuits are the biggest potential problem (as previously discussed) and the therefore short-circuit isolators should be used as necessary.

In the system you are talking about you could probably be able to install a two loop addressable panel and spur off all 12 existing zone wire cables from it via short-circuit isolators, change all the devices to addressable and you would then have an analogue addressable system without having to form the existing cables into a loop.

Obviously there are a whole number of BS5839 factors to take into account, which even for someone as 'wordy' as me, would take a long time to explain in writing. If you are seriously contemplating this option let me know and we'll make contact by phone and I'll advise you what to look out for.

[Wiz]

dum - da - da- dum -da - da - dum -da - da - dum -da - da--da!

Hey Buzz, I've been humming it and I think it's the theme tune from Bonanaza, or the Lone Ranger or, or, or??? No you'll have to tell me!

Just riding off into the sunset now,

Wiz

[Allen Higginson]

You were right first time!

[Wiz]

Wiz this is your opinion and but, I do feel that it's not correct to use spurs on a loop. As I said earlier how would you feel tracing a cable fault etc.. finding a bucket load of spurs on a system (and it happens). Not to sound smart but you are correct in saying that it's not mentioned on BS5839 (we don't use these regs anymore in a lot of cases our regs are slightly higher), but if is not mentioned in BS or any other standard does that mean that its ok, my opion is that it is not ok to use spurs in any case on a loop at the end of the day you are dealing with life and to me this is the way it is and that it isw not ok to use spurs under any case. And one of my reasons for this is how may time have you seen a spur with no isolator, it happens so often its not funny. "I maintain you shouldn't tell anyone that something is categorically wrong, when it isn't." I would tend to agree with this comment but I find that spurs are not correct and would not let any of my staff use them, to be honest I would sack them.

Don't really like to resurrect this one since there was some harsh comments made about us who disagreed that 'spurs' on addressable loops were definitely the sign of a 'cowboy' installation. However, if there is anyone who is still unsure if 'spurs' on loops are techincally possible please see this drawing on Apollo fire detectors' site that shows spurs being used:

http://www.apollo-fire.co.uk/PDFs/Typical%20loop%20configuration.pdf

If the manufacturers include them on their literature surely these prove that they are feasible

Also I would again confirm that BS5839 Part 1 2002 does not recommend against their use.

[Graeme]

Wiz

That.s exactly the diagram i was thinking of.

[FireFly40]

Conventional -no you need a 4 core.

a/a i suppose you could wire a tee off the loop and install an i/o unit at one panel.

clear throat boys and try this
In best karaoke Frank Sinatra stylee

And now the link is clear
fire panels link two cores for certain
it can be done, done it before
it works quite well and thats for sure
see my post in Q & A
and do it my way

 apologies couldnt help myself!

[Allen Higginson]

Conventional -no you need a 4 core.

a/a i suppose you could wire a tee off the loop and install an i/o unit at one panel.

clear throat boys and try this
In best karaoke Frank Sinatra stylee

And now the link is clear
fire panels link two cores for certain
it can be done, done it before
it works quite well and thats for sure
see my post in Q & A
and do it my way

 apologies couldnt help myself!

You need 2 x two cores to acheive the switching of the relay coils (which is the same as a 4 core).
Unless I'm still missing something??:/

[FireFly40]

Perhaps me not explaining it very well but I can assure any doubters it does work. If you would like the circuit I can send it to you. Ill try another brief description.
2 four pole relays in each panel dioded and suppressed and the two coils connected via 2 (two)wires the two wires go through 2 of the NC contacts in the relays to +/- and -/+ 24V on fire respectively in each panel the diodes are wired such that panel A
firing operates relay in panel B and vice versa. the spare contacts in the relays are used for class changing the panel. Wiz has a copy of drawing may be able to explain better but it really is that simple

[Wiz]

Perhaps me not explaining it very well but I can assure any doubters it does work. If you would like the circuit I can send it to you. Ill try another brief description.
2 four pole relays in each panel dioded and suppressed and the two coils connected via 2 (two)wires the two wires go through 2 of the NC contacts in the relays to +/- and -/+ 24V on fire respectively in each panel the diodes are wired such that panel A
firing operates relay in panel B and vice versa. the spare contacts in the relays are used for class changing the panel. Wiz has a copy of drawing may be able to explain better but it really is that simple

I've just got back from hols and haven't yet had time to thank FireFly for the copy of the drawing he sent me.
His circuit would definitely work, although the signal can only be in one direction at a time. You can't send a signal both ways at the same time.
Basically, a relay with two normally closed and one normally open switching contacts is connected at each of the two-wire link between panels. By connecting rectifier diodes to the coil input to each relay it is possible to make one relay operate only when a voltage is applied to the two wires in one polarity, and the other relay to operate when a voltage is applied but with the polarity reversed.
When either relay operates, it's own contacts immediately a) Disconnects the connection that would allow the other relay to operate (to ensure both different polarity voltages are not connected at the same time) and b) operates a zonal input or class change/precinct input on the appropriate panel.

[Allen Higginson]

Ok - starting too (but only just) see it now.The schematic may help it sink in further.

[FireFly40]

wiz is correct the links do only work one at a time but if the object of the game is to get bells to ring at both panels if the link is active this is already happening and theres no need for the reverse channel. This method is excellent for linking class changes. Have used it on spare zones but you need to cut links diodes etc to stop that zone tripping the aux relay and make non latch (easy on Kentec panels though).Personally if you link two separate fire panels with common bells its better to have only one panel with red lights to avoid any confusion in fire situation