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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: Benzerari on January 29, 2007, 04:50:38 PM
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Hi All;
Is there any way to link two conventional fire alarm panels, both ways, using just 2 core cable run between them?
by means if alarm goes off in panel1 it set off the panel2
and vice-versa
You can add external relays as much as you need, also to get the triggering process should happen in either forward way or backward way at the time, by means the first triggered panel would not receive back fire signal from the second.
If best solution then
member receive ££££
Else
member receive -££££
End if
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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.
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Even with a 4 core it will require a relay/ reset arrangement if you are to avoid a lock up situation, ie reset one, other one still in alarm and will reactivate the first.
If both panels have class change inputs ie non latching bells you should be OK
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Even with a 4 core it will require a relay/ reset arrangement if you are to avoid a lock up situation, ie reset one, other one still in alarm and will reactivate the first.
If both panels have class change inputs ie non latching bells you should be OK
What ever happened to fault monitoring of the cables if using class change ??
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Hi All;
Is there any way to link two fire alarm panels, both ways, using just 2 core cable run between them?
If a/a and both same make-then network them with a 2 core cable.
£50 please
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Hi All;
Is there any way to link two fire alarm panels, both ways, using just 2 core cable run between them?
If you have a twin-wire 'non-addressable' (formerly known as 'conventional') as one of the panels. It would be possible to use the same two wires as both the detection of the other panel, and the alarm to the other panel. Obviously you will need to use a relay and a twin-wire input device.
Please contact me for details of where to send the money you have promised me and confirmation of additional cost for full explanation of how to do it!
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Even with a 4 core it will require a relay/ reset arrangement if you are to avoid a lock up situation, ie reset one, other one still in alarm and will reactivate the first.
If both panels have class change inputs ie non latching bells you should be OK
What ever happened to fault monitoring of the cables if using class change ??
This is a good point David.
However, I would argue that where each panel was part of it's own individual system and each was in a physically seperated building (i.e the two panels were not actually part of the same fire system as such) this wouldn't necessarily be a problem. The link, in this case, would not be an integral part of either fire alarm system (i.e each system would function correctly, and that building's own fire alarm integrity would still be maintained without the link functioning). The link, in this case, would have been provided just as an indication of what was happening in 'the other building'. Surely in this scenario, any monitoring of the link is not an important function to maintain the individual integrity of either system.
What do you, or others, think of this argument?
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Depends on the circumstances Dr Wiz. I have found a number of modern commercial buildings, designed for letting as individual units and with full compartmentation, have been fitted each with a simple two or four zone panel, as stand alone systems.Then when a larger employer wants to occupy a number of units in the same building, and the staff need to move freely within the units, the best solution is to link the panels to create a one out all out situation - then the functionality and monitoring become more important.
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Depends on the circumstances Dr Wiz. I have found a number of modern commercial buildings, designed for letting as individual units and with full compartmentation, have been fitted each with a simple two or four zone panel, as stand alone systems.Then when a larger employer wants to occupy a number of units in the same building, and the staff need to move freely within the units, the best solution is to link the panels to create a one out all out situation - then the functionality and monitoring become more important.
Professor Kurnal! How nice to hear from you again. Keep up the good work in leading the unkowing to a better future!
Yes, in the circumstances you propose I agree totally. The overall system created by a number of systems should have the same integrity as a single system.
In my secenario, two 'standalone' systems in seprate buildings, with some sort of non-critical signalling between them, then it could be suggested that monitored linking cable is always preferable but not necessarily a requirement of BS
(p.s. - Have you heard from Lucky lately? I wonder if Matron has had him moved to another establishment? I myself have gone through a long period of boredom with the questions being asked lately and had hibernated. This one caused me to stir, however because there was talk of money being paid for my knowledge! (something that happens infrequently. Normally it is knowledge given for nothing!))
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In those circumstances I would defer to your wizdom old chap. Otherwise for me argue it would be a case of the totally unsighted leading the visually impaired.
Lucky has been running around in other wings of the institution recently trying to encourage others to join our happy band and from a couple of his posts I think he is still trying to work out how he found his way in.
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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.
OMG a spur off a loop??
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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.
OMG a spur off a loop??
Hey Genius-did i say it was a great option?
No- but it is a way of doing it with a 2 core cable as per the very original post,if you have read it?
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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.
OMG a spur off a loop??
Hey Genius-did i say it was a great option?
No- but it is a way of doing it with a 2 core cable as per the very original post,if you have read it?
Yes I did read it..... no you didn't say it was a great option but you didn't sat it was either...I'd hate to tracing a fault on one of your systems with a bucket load of spurs off it!!!!!!!
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OMG a spur off a loop??
Hey Genius-did i say it was a great option?
No- but it is a way of doing it with a 2 core cable as per the very original post,if you have read it?
Yes I did read it..... no you didn't say it was a great option but you didn't sat it was either...I'd hate to tracing a fault on one of your systems with a bucket load of spurs off it!!!!!!!
This was a hypothetical solution to a question so I wouldn't go getting thick about it - obviously you woud wire a mini loop out and in to pick up any additional device.
In response to tracing faults on a system with a bucketload of spurs on it, if you're competant then it really shouldn't be an issue.
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Hey Genius-did i say it was a great option?
No- but it is a way of doing it with a 2 core cable as per the very original post,if you have read it?
Yes I did read it..... no you didn't say it was a great option but you didn't sat it was either...I'd hate to tracing a fault on one of your systems with a bucket load of spurs off it!!!!!!!
This was a hypothetical solution to a question so I wouldn't go getting thick about it - obviously you woud wire a mini loop out and in to pick up any additional device.
In response to tracing faults on a system with a bucketload of spurs on it, if you're competant then it really shouldn't be an issue.
I not getting thick about it and yes it should be wired in a loop and that was my point but, for someone to come back with a smart assed answer like "hey genius" I think says a lot about them.. and yes I am a "competant" person but to think another person even suggesting the use of spurs off a loop ( hypothetical solution or otherwise) says a lot about their standard of work!! God only knows what they are teaching other younger and less experienced engineers........ I take from the "if you're competant then it really shouldn't be an issue" statement that you also have engaged in this practice??. standards out the window!!! They are there for a reason.
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I was not questioning your competancy and apologies for making you think so - the "you're" in this case was general.With that I'll leave the off topic posts alone as slanging matches serve no purpose.
However,the original question was "Is there any way to link two conventional fire alarm panels, both ways, using just 2 core cable run between them?" and somehow it has ended up in addressable territory.I have an inkling that HAES panels can be networked as they have a comms port onboard "but I wouldn't be sure without checking the manual" so at the moment the answer would be no (but maybe!).
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Yes I did read it..... no you didn't say it was a great option but you didn't sat it was either...I'd hate to tracing a fault on one of your systems with a bucket load of spurs off it!!!!!!!
This was a hypothetical solution to a question so I wouldn't go getting thick about it - obviously you woud wire a mini loop out and in to pick up any additional device.
In response to tracing faults on a system with a bucketload of spurs on it, if you're competant then it really shouldn't be an issue.
I not getting thick about it and yes it should be wired in a loop and that was my point but, for someone to come back with a smart assed answer like "hey genius" I think says a lot about them.. and yes I am a "competant" person but to think another person even suggesting the use of spurs off a loop ( hypothetical solution or otherwise) says a lot about their standard of work!! God only knows what they are teaching other younger and less experienced engineers........ I take from the "if you're competant then it really shouldn't be an issue" statement that you also have engaged in this practice??. standards out the window!!! They are there for a reason.
Irish Fire
you know absolutely nothing about me and i find your comments insulting.I take it you are calling me a cowboy then?
OMG is to me a smart arsed reply.
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This was a hypothetical solution to a question so I wouldn't go getting thick about it - obviously you woud wire a mini loop out and in to pick up any additional device.
In response to tracing faults on a system with a bucketload of spurs on it, if you're competant then it really shouldn't be an issue.
I not getting thick about it and yes it should be wired in a loop and that was my point but, for someone to come back with a smart assed answer like "hey genius" I think says a lot about them.. and yes I am a "competant" person but to think another person even suggesting the use of spurs off a loop ( hypothetical solution or otherwise) says a lot about their standard of work!! God only knows what they are teaching other younger and less experienced engineers........ I take from the "if you're competant then it really shouldn't be an issue" statement that you also have engaged in this practice??. standards out the window!!! They are there for a reason.
Irish Fire
you know absolutely nothing about me and i find your comments insulting.I take it you are calling me a cowboy then?
OMG is to me a smart arsed reply.
Well that's the way you consider it, and for that I'm sorry. I am not saying you are a cowboy but, you make a suggestion like that you leave yourself wide open for a comment....... (fair is fair) making suggestions like use a spur off a loop is in any competent and professional persons book "cowboy" style work!!! And regardless of what comment you may come back with you made the suggestion so you have left it open for the opinion that you would partake in this crazy and unprofessional type of work. Just consider the reaction if you said it in a job interview? Would you get the job? I know I would not employ anyone who made a suggestion like that. Now I am sorry if you are insulted by my comments but, you did make the comment in the first place. An old Army Sgt I worked with had a great expression "You stick your head out of the bunker you expect to get shot" And again I say sorry if I have offended you and I don't wish to start a "row" over something stupid like this but a fair comment is a fair comment. Does it not annoy you when you see work like this? I know it drives me up the bloody wall and to be honest I've sacked lads for less (maybe I have obsessive compulsive disorder!! my wife thinks seems so lol) anyway, I think we have gotten off on the wrong foot and I hope this will not affect any future comments made here and again I'm sorry if I have offended you.
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Amen??
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Amen??
we will see, I hope this is the end
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Blimey, normally I'd have to visit the local bowling alley or watch an episode of "Tricia" for such entertainment.......!
But broadening the subject slightly, what is wrong with spurs off loops where the system is designed for that purpose. The obvious example being Gent "T" breakers.
If a short circuit isolator is installed either side of a spur I don't see the problem.
A lot of system manufacturers sell their kit blatantly advertising the fact you can "spur" off their loops.....!
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Blimey, normally I'd have to visit the local bowling alley or watch an episode of "Tricia" for such entertainment.......!
But broadening the subject slightly, what is wrong with spurs off loops where the system is designed for that purpose. The obvious example being Gent "T" breakers.
If a short circuit isolator is installed either side of a spur I don't see the problem.
A lot of system manufacturers sell their kit blatantly advertising the fact you can "spur" off their loops.....!
Is it not the case when you do this that it is no longer a loop? it's as easy to pull in a 4 core as a 2 core. I just hate to see spurs being used.
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Blimey, normally I'd have to visit the local bowling alley or watch an episode of "Tricia" for such entertainment.......!
But broadening the subject slightly, what is wrong with spurs off loops where the system is designed for that purpose. The obvious example being Gent "T" breakers.
If a short circuit isolator is installed either side of a spur I don't see the problem.
A lot of system manufacturers sell their kit blatantly advertising the fact you can "spur" off their loops.....!
Is it not the case when you do this that it is no longer a loop? it's as easy to pull in a 4 core as a 2 core. I just hate to see spurs being used.
But if a 4 core is used and it is damaged then you are in the same position as if you had used a two core (ie - loss of detection on that circuit).
Any chance that this thread can be closed as it has drifted well off the original post?
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The last word.
Amen.
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After reading this I set my self the challange of linking the panels with a 2 core and think ive managed it (unfortunatly not monitored)
im happy to send jpg of the circuit diagram to anyone that asks but please check it as ive not tested it
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After reading this I set my self the challange of linking the panels with a 2 core and think ive managed it (unfortunatly not monitored)
im happy to send jpg of the circuit diagram to anyone that asks but please check it as ive not tested it
Please do: cathalvkeogh@eircom.net I'd like to see that, we're all on a learning curve
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you could use your 2 core to link 2 relays together surely?
basically wire a relay at each panel, being hit with 24v on fire condition, and then basically use the 2 core to link the 2 coils. doubt it would be compliant with any sort of standard, and you'd basicallly be in the situation where the panels may be unresettable without powering them down, but the 2 core linking the 2 coils would mean that when one panel had a fire, both relays would activate, one at each panel, and you could then use that relay to do whatever you need to do to activate the panel(s)
if you used the relays to hit a class change contact then you wouldn't be faced with the problem of unresettable panels, but it doesn't sound like too safe a set up :D
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ive now posted the jpeg of my wiring diagram at
http://www.fileden.com/files/2006/11/4/347602/2%20wire%20panel%20link.jpg
if ive got it right which i think i have you can have as many panels as you like connected on the 2 core they wont lock up and all silence when panel (or panels) that are in fire are silenced
please check out my work and let me know if there is any problem with it (apart from the obvious fact that it isnt monitored)
Ray
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ive now posted the jpeg of my wiring diagram at
http://www.fileden.com/files/2006/11/4/347602/2%20wire%20panel%20link.jpg
if ive got it right which i think i have you can have as many panels as you like connected on the 2 core they wont lock up and all silence when panel (or panels) that are in fire are silenced
please check out my work and let me know if there is any problem with it (apart from the obvious fact that it isnt monitored)
Ray
It looks like it works ok and it's good that it shows that the CC has activated via the external signal.The only thing is that it won't silence unless the other panel resets - fire relays (unless configured) don't change state on silence,only on a reset.
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ive now posted the jpeg of my wiring diagram at
http://www.fileden.com/files/2006/11/4/347602/2%20wire%20panel%20link.jpg
if ive got it right which i think i have you can have as many panels as you like connected on the 2 core they wont lock up and all silence when panel (or panels) that are in fire are silenced
please check out my work and let me know if there is any problem with it (apart from the obvious fact that it isnt monitored)
Ray
It looks like it works ok and it's good that it shows that the CC has activated via the external signal.The only thing is that it won't silence unless the other panel resets - fire relays (unless configured) don't change state on silence,only on a reset.
sorry your quite right. ive got kentec panels in my head that have 2 sets of fire contacts one of them that duplicates the bells. how about wiring one of the bell circuits via the relay coil (diode suppressed ) instead of using the alarm contacts. would that meet standards?
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Put two HAES conventional panels in (for example!!) and network them via your two core would keep everyone happy!!Provided you supress the relays you could use the sounder outputs to hit the relay coil.
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with some panels, u can use the 24v alarm output that becomes live when the panel goes into fire (just 2 cores, + and -)
connect it to a timer relay in the other panel to make a closed connection when the delay is up and connect it to the EVAC terminals that sound the bells when they are shorted.
just a possibility that ive seen used on one site, where when the building next door goes off, they have 3mins to confirm or silence before the building next door is tipped out.
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Wow! I went away for a quick ski and obviously some things got a bit warm around here! If Matron finds out there has been so much feistiness in our members then she might increase the dosage of our medication!
I'd like to add my comments in respect of a number of the recent posts as follows:
1) There is nothing in BS5839 that indicates it is wrong to install a spur on an addressable loop, with or without any isolating device, other than the recommendation to ensure that a single wiring fault does not disable protection in an area of more than 2,000m2.
Spurs can be useful/necessary even for the best fire alarm engineers. I can't see a spur on an addressable system being any harder to fault-find on than one without a spur, in most circumstances. Having spurs does not make anybody a cowboy (especially not G.M. who has proven his credentials on this site on numerous previous occasions)
-To be a cowboy, as well as spurs, you would also need guns, a hat and a horse!
2) Surely the 'two wires between the two non-addressable panel' question must be based on panels that have latching fire zone inputs? If you have panels with class change inputs and aux. fire relays that do not operate on class change, but do on fire conditions, then you don't need any extra relays at all - so this can't be the solution to the original question. I thought my previous answer to use a twin/sav/two wire panel was a 'wizard' solution and I thought the promised 'big bucks' would be winging their way to my account in time to pay for my next ski holiday.
3) The Haes 'network' solution proposed by Buzzard is also a good one. The Haes Envoy expandable takes a two-wire network card that would allow seperate panels to operate as one system. (Please note that the Envoy Extendable is for a maximum of 4 fire zones)
4) Can we stop using the term 'conventional' in respect of fire systems? Matron has told us that systems are now either 'addressable' or 'non-addressable'. Conventional died with the 2002 update and I attended the funeral.
I know that we all conventionally called 'non-addressable' panels 'conventional' previously, but current conventions suggest that we should address the issue properly and do as Matron advises. If necessary we could form a panel to discuss and/or address the convention of the proper address for conventional panels or non-addressable panels and hopefully reach a conventional and rational conclusion. Or maybe not.
p.s This has been approved by our legal department.
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Spurs can be useful/necessary even for the best fire alarm engineers. I can't see a spur on an addressable system being any harder to fault-find on than one without a spur, in most circumstances. Having spurs does not make anybody a cowboy (especially not G.M. who has proven his credentials on this site on numerous previous occasions)
-To be a cowboy, as well as spurs, you would also need guns, a hat and a horse!
Are you saying it's ok to use spurs??
I thought this was put to bed (although if you had bothered your arse to read the posts correctly you would have seen that it was or are you just trying to stir up ****??
As for the hat and guns comment well that says it all!!!
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To IrishFire:
Yes, I really have only just seen the posts. Even I deserve a holiday.
No, I am not trying to stir things up. I thought the matter of spurs had not been resolved. I noted that the thread had deteriorated into some nasty comments and I tried to ignore this, but it seemed to me that the main point had not been resolved and that Graeme's comment on spurs was made to appear to be wrong. I had in fact 'been arsed' (what a wonderful turn of phrase you employ!) to read all the posts and it seemed to me the impression had been given that spurs on addressable systems were just not allowed. This is not the case.
Yes, There is nothing in BS5839 that stops you using spurs on addressable systems as long, of course, as it doesn't affect other recommendations.
Yes, I found the mention of 'spurs' and 'cowboys', too good an opportunity to miss making a light-hearted comment on. Surely we are meant to be sharing knowledge and opinions in a friendly manner. I like to do this in a light-hearted way. There is already too much aggravation in life to take some matters too seriously. Although I can do whatever is necessary as the situation demands.
No, I don't understand why my 'hats and guns' comment says anything in particular. I'm sure you'd like to explain.
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Welcome back Dr Wiz.
You are just in the nick of time- everybody seems to want to shout at each other or shoot each other up. The homes not apache of what it used to be.
The best convention may be to address each other in a polite and friendly manner.
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Professor K, Always nice to hear from you. How nice to find you are still a resident in the home!
Yes, all this beating of drums and war-dancing is very worrying. I couldn't believe the sort of arrows being fired in Graeme's direction. I hope he survived. If this sort of thing carries on I can even see an eventual Sioux-ing situation or even another battle of the little big fire alarm horn. Heap bad medicine.
I'm still waiting to be addressed but it wouldn't surprise me if the protocol is going to be corrupted and I get a lot of rubbish being returned.
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Wiz-i survivied and thanks for your comments.
Regards
G
p.s i hope the ski-ing was good? I fancy going on the piste all weekend..no ski's needed though.
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Professor K, Always nice to hear from you. How nice to find you are still a resident in the home!
Yes, all this beating of drums and war-dancing is very worrying. I couldn't believe the sort of arrows being fired in Graeme's direction. I hope he survived. If this sort of thing carries on I can even see an eventual Sioux-ing situation or even another battle of the little big fire alarm horn. Heap bad medicine.
I'm still waiting to be addressed but it wouldn't surprise me if the protocol is going to be corrupted and I get a lot of rubbish being returned.
Wonderful tripe!!!!!!!
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Irishfire
Tripe it most certainly is but it is completely inoffensive and light hearted unlike some of your comments.
The forum is whatever you want it to be. Nobody has to read it or to comment.
For me I spend usually 7 days a week assessing premises then writing the most boring, factual and technical reports, policies and procedures you have ever seen. This forum is a bit of light relief but along the way it also helps a lot of people free of charge.
In 33 years in the industry I have learned that nothing is ever absolutely clear cut. There are different opinions and sometimes these can cause us all to review our long held views.
The issue of spurs on a loop is a very interesting one and I would love to see it taken to a conclusion. I do not have the expertise to comment either way but am interested in learning fom all of you techies.
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Irishfire
Tripe it most certainly is but it is completely inoffensive and light hearted unlike some of your comments.
The forum is whatever you want it to be. Nobody has to read it or to comment.
For me I spend usually 7 days a week assessing premises then writing the most boring, factual and technical reports, policies and procedures you have ever seen. This forum is a bit of light relief but along the way it also helps a lot of people free of charge.
In 33 years in the industry I have learned that nothing is ever absolutely clear cut. There are different opinions and sometimes these can cause us all to review our long held views.
The issue of spurs on a loop is a very interesting one and I would love to see it taken to a conclusion. I do not have the expertise to comment either way but am interested in learning fom all of you techies.
As I said in an earlier comment this issue WAS put to bed and I said if the postings were read correctly this conversation would not be happening would it??
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I am pretty certain, and most pleased, that the only aspect of this post that appeared to have previously been 'put to bed' was the unseemly nasty comments being made between some members.
However, the simple fact is, many strong negative comments have been made about the use of 'spurs' on addressable systems and these have not only not been put to bed, they haven't even been discussed.
The following are an example of some of the comments (whilst not mentioning who made them):
........making suggestions like use a spur off a loop is in any competent and professional persons book "cowboy" style work!!! And regardless of what comment you may come back with you made the suggestion so you have left it open for the opinion that you would partake in this crazy and unprofessional type of work. Just consider the reaction if you said it in a job interview? Would you get the job? I know I would not employ anyone who made a suggestion like that. .......... Does it not annoy you when you see work like this? I know it drives me up the bloody wall and to be honest I've sacked lads for less ......
I have re-read all the posts and have not seen any retraction of the above comments.
Graeme originally made the comment about using a spur on an addressable system as a solution to a particular problem. The responses to this have suggested that he was totally wrong to even consider it because there is something seriously wrong in doing so. I suggest that Graeme has previously shown that he is no mug when it comes to technical matters so his views should always merit proper consideration.
In my opinion the general concept of using a spur on an addressable system is perfectly o.k. both technically and within the recommendations of BS5839 part 1 2002. I welcome any considered views to the contrary for discussion.
Even if Graeme made a suggestion that was definitely wrong , then surely a gentle query of his suggestion and the start of a discussion would be the right way to move forward. If we all go straight for the 'jugular' on people who 'make a mistake or get it wrong' then no-one will ever dare ask a question or propose a different viewpoint. Surely, we all visit this site to learn, educate and be able to discuss subjects that we are all interested in with like-minded people, and not to be rude to them (intentionally or not)
Prof. K has said he is interested in learning more about this 'spur' question and I would therefore propose the following explanation for his consideration (the rest of you can ignore this if you want!):
The pulse signals that form the method of communication between the control panel and the addressable devices are transmitted over the same pair of wires that also power the devices.
In fact, from a technical point of view the addressable communication would still work even with a whole two-wire radial circuit containing loads of tees and spurs etc. It doesn't need a loop to function.
Most addressable systems in fact only communicate from one end of a typical loop circuit whilst that loop is complete i.e. in real terms it is communicating along a two wire radial circuit from the 'loop out' terminals in the panel right to the other end of the cable.
The communication pulses only start to also transmit from the panel into other end of the loop only when the loop is detected as broken.
If addressable circuits were wired only as radials then the BS recommendation that a single wiring fault should not affect the protection in an area greater than 2000 m2 would apply. However when they are wired as loops (and capable of communication from each end) then the BS recommendation of two simultaneous wiring faults not affecting protection in an area of greater than 10,000m2 applies. i.e one loop can cover up to 10,000m2 wheras it would mean that if only 'addressable radials' were used, you would need five addressable radial circuits to cover the same area as a loop. This is the only reason I know why addressable systems are generally wired as loops
So there is nothing to stop anyone using radial circuits, radial circuits with 'spurs' or loops with radial 'spurs'. However because a single wiring fault shouldn't affect the protection in an area greater than 2000m2 then any two-wire radial, tee or spur should never cover an area greater than this.
In the above explanation it is assumed that Prof. K is also aware of the importance of the role of short-circuit isolators in addressable systems (If not Prof. , then please let me know)
I would confirm that my view is only that it is wrong to categorically say or infer that spurs are not allowed in any format in addressable systems when there appears to be no technical or leglislative reasons to totally disallow them.
I admit that there are a lot of practical benefits in keeping as much of any addressable system as a loop wherever possible, but this is not the point. I maintain you shouldn't tell anyone that something is categorically wrong, when it isn't.
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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.
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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.
Irishfire, how nice to have a considered discussion with you. Yes, I agree that you are perfectly entitled to demand that your staff do not use spurs on addressable systems. However, I maintain that it does not mean that anybody else using them is wrong or incompetent or a 'cowboy' in doing so.
Despite what you might think of the technical Standards, these are probably the only thing (apart from manufacturer's specific instructions in respect of their own equipment) that we can all use to determine and hopefully agree exactly what is and what isn't 'allowed'.
I agree that the use of 'spurs' can sometimes make fault-finding a bit more difficult. However, using them in a system, with due regard to BS recommendations, does not necessarily make such a system less reliable or less good or less compliant than every system wired as a loop. I welcome any discussion on this opinion.
The reason I have 'highlighted' this matter is because I believed the comments made about the use of 'spurs' were wrong and misleading. Many people use this site to 'learn' new things and it is important that we all try to ensure that anything that is stated as a 'fact' rather than an opinion is 100% correct.
People often tell me that something has to be done a certain way because it says so in the Standards. When I ask them to direct me to that particular recommendation in the Standard, they then advise me that, in fact, they haven't seen it themselves but were actually 'told by someone else' that 'they had to do it this way' and then assumed that this was the only way detailed in the Standards. I think this is similar to 'Chinese whispers'.
I hoping that you will now agree with the conclusions that I have now reached about this matter as follows:
1) It is o.k., both technically and also in respect of the recommendations in BS5839 part 1 2002, to have radial spurs connected to addressable loops as long that any single wiring fault does not affect the protection covering an area of a maximum of 2,000m2.
2) That in your opinion you do not like the use of radial spurs to addressable loops sytems. However you can't say it is 'incorrect' to use them
3) Anyone using radial 'spurs' on an addressable loop is not necessarily incompetent or a 'cowboy'
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Thanks Wiz for your explanation. I would be grateful to see your expanation of the role of short circuit isolators, I guess that without it a single wiring fault on a loop would potentially take out the entire loop and on a radial any device beyond the isolator? That on a conventional system a short circuit would effectively cause the thing to go into alarm mode (ie fail safe of sorts) but on an addressible the signalling would be lost so we would get communication faults only?
Like I have said before I only drive the things but an insight into the technical side is always useful. I do often refer to the BS (which I can understand as far as it goes) and always read the system manuals (which are usually double dutch) so that I can write the fire procedures and test instructions for the responsible person. But the trouble with the manuals of course is that they tend to assume full technical understanding as a starting point.
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Thanks Wiz for your explanation. I would be grateful to see your expanation of the role of short circuit isolators, I guess that without it a single wiring fault on a loop would potentially take out the entire loop and on a radial any device beyond the isolator? That on a conventional system a short circuit would effectively cause the thing to go into alarm mode (ie fail safe of sorts) but on an addressible the signalling would be lost so we would get communication faults only?
Like I have said before I only drive the things but an insight into the technical side is always useful. I do often refer to the BS (which I can understand as far as it goes) and always read the system manuals (which are usually double dutch) so that I can write the fire procedures and test instructions for the responsible person. But the trouble with the manuals of course is that they tend to assume full technical understanding as a starting point.
a conventional panel going into alarm would only happen if it were a short circuit = fire panel.
most panels these days need a 560ohm resistance to put the panel into fire, a short circuit would just show a fault (or on many panels, it would actually display as a short circuit fault)
on addressable systems, a short circuit will drop the power from the cables to prevent damage to the panel and to detectors. without isolators, the entire loop would be lost (each loop connection in the panel normally has a built in isolator) with isolators, only the section of the cables in fault between the nearest two isolators in either direction would be lost.
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Mr K. - yes, a short-circuit on an addressable loop wiring will invariably ruin the communication pulses and therefore short-circuit isolators should be installed which automatically disconnect the wiring whenever the extra current drawn by a short-circuit is detected.
In practise, the isolators either side of any short-circuit fault both operate so as to disconnect that section of the loop from the rest of the system. The remaining addressable devices still connected to the control panel should now continue operating and communicationg with the control panel.
Obviously, the greater the number of short-circuit isolators on a loop the smaller the section of the circuit that gets isolated in any fault situation. It is becoming more popular to have short-circuit isolators built into each piece of addressable equipment. However some people say that the more isolators you have, then the more chance you have of suffering a fault due to the failure of one of them!
Equipment manufacturers normally advise a the minimum number of short-circuit isolators that would be required on any loop and this figure is based on how much current is normally being drawn by the equipment connected to the loop. Obviously, the total amount of current being drawn in normal operation shouldn't cause any short-circuit isolators to operate.
However there are also specific recommendations in respect of the number and location of short-circuit isolators in BS5839 part 1 to ensure that when they operate that the maximum section of the loop that is disconnected, is kept to well-defined limits and which generally tie-in with the traditional maximum fire zone size of 2,000m2. Also where loop-powered addressable sounders are used, there are specific recommendations in respect of such sounders being installed close to the panel and the short-circuit isolators then required.
On non-addressable systems it doesn't really matter what specific effect a single
wiring fault has on a fire zone since that fire zone should generally not be protecting an area greater than 2000m2 anyway. In real terms, a short-circuit on non-addressable zone wiring caused a fire condition on earlier BS systems but these days a full short-circuit should give a fault condition. Obviously if such a short-circuit was resistive to the amount that it passed approximately the same current as a device going in to alarm, then this would obviously give a fire condition even on a current model non-addressable panel.
One point to watch with all short-circuit isolators on any addressable loop is to ensure that they all isolate the same wire on the loop i.e either the +ve or -ve otherwise there is no or reduced protection. For example Apollo sell both +ve and -ve short-circuit isolators and the correct ones should be selected specifically for each project. Most addressable panels have short-circuit isolators in-built on both the 'out' and the 'in' loop connections and the loop installed short-circuit isolators should work on the same 'leg' as these.
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That in your opinion you do not like the use of radial spurs to addressable loops sytems. However you can't say it is 'incorrect' to use them
I feel I can say it's incorrect to use them..regulations are there as a guide and are not set in stone. It is my opinion that anyone who pulls in a single 2 core cable to apply to a fire loop instead of either 2 x 2 core cables or a 4 core cable is cutting corners for the sake of cost or laziness and therefore is in my opinion a "cowboy" and i'm sorry but i will find it very hard to change my mind on this one. I might like a fussy ol' git on this one but, (my wife will say yes on this one) the option of using spurs are coverd in the regs etc.. but does that mean its ok to use them? I think even the people who set the regulations would say it's not ok to use them but they need to cover all angles (maybe I'm wrong)
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a common mistake that can be made with regards to amount of devices between isolators is counting every thing on the loop as 1 device.
i.e Apollo 20 device isolator with say 18 opticals and 2 100dba loop sounders between isolators actually has 22 devices as the sounders counts as two based on the value of switch on surge current which is 1.8ma
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a common mistake that can be made with regards to amount of devices between isolators is counting every thing on the loop as 1 device.
i.e Apollo 20 device isolator with say 18 opticals and 2 100dba loop sounders between isolators actually has 22 devices as the sounders counts as two based on the value of switch on surge current which is 1.8ma
Happens so often it's not funny. The biggest problem I find is people trying to put too many sounders on a loop. Had one last year with 52 Apollo sounders per loop (5 loop Morley).
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Thanks to all. May I continue with a few supplementary questions?
An I right in deducing that a short circuit isolator is a completely passive device on the loop, that does not have its own identity or address and if it operates the fault will only be dentified by the failure to communicate with the devices on the isolated part of the loop?
And is the isolator an intelligent device that can monitor the potential conditions on the isolated part of the loop and reset itself when the short circuit appears no longer to exist or does it need to be manually reset like an MCB or replaced like a fuse?
I am having difficulty trying to visualise just how these isolators can monitor and isolate sections of a loop - thinking of Kirchoffs Law which said that the total current flowng in a circuit (loop?) = the sum of all the currents flowing in all parts of the circuit. I am now thinking that when you wire an alarm loop it must effectively look like a ladder with a main conductor ( Unprotected?)running up the strings of the ladder and across the top rung (we operational chaps call these rounds) and then each rung of the ladder having a number of devices ( ie a fire zone) with a short circuit isolator at either side of the rung (fire zone)?
Finally I sometimes see fault messages on systems such as "Loop split on +ve line". I have always assumed this to be a wiring fault due to a defective connection but from your last point Wiz it could be something else?
Thanks for your contribution to my continuing education. Wiz- I owe you a bottle of your favourite medicine!
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A SCI can be incorporated into a device,detector base or stand alone.
The SCI itself has no address and when a short on a cable occurs the isolator either side of the fault open circuit,which then isolates that faulty cable run.
The panel will show a loop open circuit fault and communications faults for all the devices that have been isolated on the affected cable run.
When the short is removed the islolators automatically reset.The isloators that have been affected will normally show an amber led.
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a common mistake that can be made with regards to amount of devices between isolators is counting every thing on the loop as 1 device.
i.e Apollo 20 device isolator with say 18 opticals and 2 100dba loop sounders between isolators actually has 22 devices as the sounders counts as two based on the value of switch on surge current which is 1.8ma
Yes, the figure of 20 is arbitary. It all depends on the currents being drawn by the devices between the isolators. With the original loop-powered beam detectors from Apollo I found it best never to install more than 1 or 2 between isolators. I've noticed that the latest versions are supplied with integral short-circuit isolators.
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The biggest problem I find is people trying to put too many sounders on a loop. Had one last year with 52 Apollo sounders per loop (5 loop Morley).
I've noticed that many newer addressable panels are providing higher loop current capabilities. A few manufacturers are currently advertising 50 loop powered sounders as a possibility. So what seems impossible now will be a reality in a few years!
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That in your opinion you do not like the use of radial spurs to addressable loops sytems. However you can't say it is 'incorrect' to use them
I feel I can say it's incorrect to use them..regulations are there as a guide and are not set in stone. It is my opinion that anyone who pulls in a single 2 core cable to apply to a fire loop instead of either 2 x 2 core cables or a 4 core cable is cutting corners for the sake of cost or laziness and therefore is in my opinion a "cowboy" and i'm sorry but i will find it very hard to change my mind on this one. I might like a fussy ol' git on this one but, (my wife will say yes on this one) the option of using spurs are coverd in the regs etc.. but does that mean its ok to use them? I think even the people who set the regulations would say it's not ok to use them but they need to cover all angles (maybe I'm wrong)
Once again I will state that my only problem has been that previous comments could be interpreted as confirmation that spurs were not allowed under the BS 5839 recommendations that most of us work to, when this is absolutely not the case, and furthermore that anyone who did so, was not necessarily incompetent or a cowboy.
Here is a scenario where, I'm sure you will agree, using a spur is the best option:
A customer decides to upgrade his existing non-addressable system to an addressable system. One of the existing non-addressable zones consists of a dozen smoke detectors in an area where the installation of new cabling is prohibitively expensive. The existing cable is in perfect condition and meets all current standards. To install additional cable will mean spending tens of thousands of pounds and waiting months for permission to do so from National Heritage.
Therefore this original non-addressable zone is converted into a spur off the new addressable system and suitably protected by short-circuit isolators. No additional cable needs to be installed and the benfits of addressable detection are provided in this area. This is a solution acceptable within the recommendations of BS5839 Part 1 2002.
Although you may not like them, and I agree with some of your reasons for doing so, it is important that readers of this forum are aware that spurs on addressable systems are perfectly acceptable within the specific recommendations of BS 5839 previously mentioned.
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Thanks to all. May I continue with a few supplementary questions?
An I right in deducing that a short circuit isolator is a completely passive device on the loop, that does not have its own identity or address and if it operates the fault will only be dentified by the failure to communicate with the devices on the isolated part of the loop?
And is the isolator an intelligent device that can monitor the potential conditions on the isolated part of the loop and reset itself when the short circuit appears no longer to exist or does it need to be manually reset like an MCB or replaced like a fuse?
I am having difficulty trying to visualise just how these isolators can monitor and isolate sections of a loop - thinking of Kirchoffs Law which said that the total current flowng in a circuit (loop?) = the sum of all the currents flowing in all parts of the circuit. I am now thinking that when you wire an alarm loop it must effectively look like a ladder with a main conductor ( Unprotected?)running up the strings of the ladder and across the top rung (we operational chaps call these rounds) and then each rung of the ladder having a number of devices ( ie a fire zone) with a short circuit isolator at either side of the rung (fire zone)?
Finally I sometimes see fault messages on systems such as "Loop split on +ve line". I have always assumed this to be a wiring fault due to a defective connection but from your last point Wiz it could be something else?
Thanks for your contribution to my continuing education. Wiz- I owe you a bottle of your favourite medicine!
Professor K. Please save the medicine for the next potting shed midnight meeting of the old codgers club. If Matron finds it in my room I'm in big trouble after all the palaver with the pavlova that Lucky 'borrowed' from the kitchen and hid in my bedside cabinet.
Graeme has suitably answered and confirmed some of your queries on the short-circuit isolator question.
I think your ladder analogy is probably not correct. Of course, I could have misunderstood it since I have a fear of heights! Instead, Just think of a two wire loop of cable where all your addressable devices are connected across the two wires. At suitable positions around the loop a number of short-circuit isolators are also connected across the loop. If a short-circuit occurs at any point of the loop then the isolators nearest (either side) the fault will automatically disconnect the loop at these two isolators. I.e. the section of cable with the short-circuit is now isolated from the control panel. The control panel now communicates along each of the ends of the loop still connected to the panel. Only the addressable devices on the section of the loop now isolated by the isolators are no longer functioning correctly. If the short-circuit is removed then the isolators automatically reset.
With respect to the other part of your question concerning our good friend Kirchoff (he has now been moved to room 4 on the first floor - next to the lift) I think I can understand your concerns. I believe your question asks why the current flowing through the isolator nearest the panel is not so great, even under non-short circuit fault conditions, that it doesn't automatically isolate?. This is because the short-circuit isolators don't actually measure the current flowing through the circuit. They are in fact looking for the normal operating voltage of the loop to drop quite drastically as an indication of a fault. I believe the voltage needs to drop to about 15 Volts for an isolator to operate. This voltage reduction will happen whenever there is a short-circuit on the loop because the maximum current that can be drawn by the loop is limited by the loop driver card circuitry and a consequence of this limting is a reduction in loop voltage during a short-circuit. Obviously a low resistance short-circuit will try to draw a lot of current.
My understanding is that this monitoring of loop voltage is carried out by the isolators a number of times a second and once the isolator nearest the short-circuit fault automatically disconnects the faulty section of the circuit, then the operating voltage will return to normal on the non-faulty sections.
I hope the above makes sense, (isolators measure voltage not current) if not please let me know and I'll try and find a better explanation.
Actually, this thread has gone way off target and I think this may have clouded the issue of the original promise of payment for a solution to the problem of connecting two fire panels together over a pair of wires. I need the money to pay for an escape attempt from the home. I understand that a tunnel is being dug from the sluice room in the East wing and I want to be included.
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Thanks Wiz I am happy now, It all makes sense now Dr Kirchoff has been put back to bed in the isolation wing of the care ohm for the bewildered.
But dont be too quick to throw away my ladder- you may need it to climb down into the tunnel. And my advice before you start digging is pick a sluiceroom on the ground floor of the building.
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That in your opinion you do not like the use of radial spurs to addressable loops sytems. However you can't say it is 'incorrect' to use them
I feel I can say it's incorrect to use them..regulations are there as a guide and are not set in stone. It is my opinion that anyone who pulls in a single 2 core cable to apply to a fire loop instead of either 2 x 2 core cables or a 4 core cable is cutting corners for the sake of cost or laziness and therefore is in my opinion a "cowboy" and i'm sorry but i will find it very hard to change my mind on this one. I might like a fussy ol' git on this one but, (my wife will say yes on this one) the option of using spurs are coverd in the regs etc.. but does that mean its ok to use them? I think even the people who set the regulations would say it's not ok to use them but they need to cover all angles (maybe I'm wrong)
Once again I will state that my only problem has been that previous comments could be interpreted as confirmation that spurs were not allowed under the BS 5839 recommendations that most of us work to, when this is absolutely not the case, and furthermore that anyone who did so, was not necessarily incompetent or a cowboy.
Here is a scenario where, I'm sure you will agree, using a spur is the best option:
A customer decides to upgrade his existing non-addressable system to an addressable system. One of the existing non-addressable zones consists of a dozen smoke detectors in an area where the installation of new cabling is prohibitively expensive. The existing cable is in perfect condition and meets all current standards. To install additional cable will mean spending tens of thousands of pounds and waiting months for permission to do so from National Heritage.
Therefore this original non-addressable zone is converted into a spur off the new addressable system and suitably protected by short-circuit isolators. No additional cable needs to be installed and the benfits of addressable detection are provided in this area. This is a solution acceptable within the recommendations of BS5839 Part 1 2002.
Although you may not like them, and I agree with some of your reasons for doing so, it is important that readers of this forum are aware that spurs on addressable systems are perfectly acceptable within the specific recommendations of BS 5839 previously mentioned.
you could also use a ZMU as another option.
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That in your opinion you do not like the use of radial spurs to addressable loops sytems. However you can't say it is 'incorrect' to use them
I feel I can say it's incorrect to use them..regulations are there as a guide and are not set in stone. It is my opinion that anyone who pulls in a single 2 core cable to apply to a fire loop instead of either 2 x 2 core cables or a 4 core cable is cutting corners for the sake of cost or laziness and therefore is in my opinion a "cowboy" and i'm sorry but i will find it very hard to change my mind on this one. I might like a fussy ol' git on this one but, (my wife will say yes on this one) the option of using spurs are coverd in the regs etc.. but does that mean its ok to use them? I think even the people who set the regulations would say it's not ok to use them but they need to cover all angles (maybe I'm wrong)
Once again I will state that my only problem has been that previous comments could be interpreted as confirmation that spurs were not allowed under the BS 5839 recommendations that most of us work to, when this is absolutely not the case, and furthermore that anyone who did so, was not necessarily incompetent or a cowboy.
Here is a scenario where, I'm sure you will agree, using a spur is the best option:
A customer decides to upgrade his existing non-addressable system to an addressable system. One of the existing non-addressable zones consists of a dozen smoke detectors in an area where the installation of new cabling is prohibitively expensive. The existing cable is in perfect condition and meets all current standards. To install additional cable will mean spending tens of thousands of pounds and waiting months for permission to do so from National Heritage.
Therefore this original non-addressable zone is converted into a spur off the new addressable system and suitably protected by short-circuit isolators. No additional cable needs to be installed and the benfits of addressable detection are provided in this area. This is a solution acceptable within the recommendations of BS5839 Part 1 2002.
Although you may not like them, and I agree with some of your reasons for doing so, it is important that readers of this forum are aware that spurs on addressable systems are perfectly acceptable within the specific recommendations of BS 5839 previously mentioned.
you could also use a ZMU as another option.
Yes Graeme, we could, but this would give us no advantages over the existing non-addressable. We want to give the customer the benefits of an addressable system in the area in question but on an existing radial cable that we can't use as part of a loop. So we use this cable as a spur off the addressable loop, fit addressable detectors etc.. We are left with all the advantages of addressable and still comply with BS 5839 Part 1 2002
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very true Wiz,just thinking that if the customer was a tight ar5e.
g
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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!!
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dum - da - da- dum -da - da - dum -da - da - dum -da - da--da!
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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.
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Puting in systems for the stars now Buz?
Sylvester Stallone's son?
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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.
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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
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You were right first time!
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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.
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Wiz
That.s exactly the diagram i was thinking of.
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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!
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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??:/
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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
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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.
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Ok - starting too (but only just) see it now.The schematic may help it sink in further.
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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
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Just as a matter of interest, thanks to Ray Snell by the way, the 2 wire linking system will also work if linking into an addressable system.
Using an I/O or Switch Monitor and I/O as the "non-addressable" panel part.
Myself and Benzerari will test this circuit out and let you know the outcome....
Regards
Paul