Brian c Posted February 17, 2005 Posted February 17, 2005 is it not standard practice to wire all things controlled by a fire alarm relay to be normally closed. If the panel failed or any cables were cut/burned, the redcare/maglocks/fans/vents/gas, etc would still operate as they would in alarm. If you don't know......ask.
secboy Posted February 17, 2005 Posted February 17, 2005 Yes but same arguement applies to auxilary equipment 40842[/snapback] Idont quite agree with that if you are saying that the aux wiring could be 8core- if cable to relay designed to close down ventilation duct and fans cannot operate a fire would be fed with oxygen and engulf people within the building as smoke kills the most people it would directly lead to loss of life even if the alarm had gone off? Paul.
secboy Posted February 17, 2005 Posted February 17, 2005 is it not standard practice to wire all things controlled by a fire alarm relay to be normally closed.If the panel failed or any cables were cut/burned, the redcare/maglocks/fans/vents/gas, etc would still operate as they would in alarm. 40844[/snapback] Yep nice one but just because you have wired a relay so that if power is lost it will still trigger do you not do your best to protect that cable "as well"??? I would prefere not to assume any thing but build into the system survivability.Paul
breff Posted February 17, 2005 Posted February 17, 2005 Brian, Chances are all insulation would melt and all cores would short together, therefore staying closed circuit. The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)
secboy Posted February 18, 2005 Posted February 18, 2005 Brian,Chances are all insulation would melt and all cores would short together, therefore staying closed circuit. 40879[/snapback] I think the idea is that the relay is energised at all times and de-energised to operate the auxilary equipment therefore if the cable was burnt and the cores shorted power would be lost to the relay the relay would drop out and the relay contacts would change state operating the aux equipment!!!(right or wrong??)
Guest Bell-man Posted February 18, 2005 Posted February 18, 2005 Here here that man. Every individual must be competant to do the job. If you don't know the standards then you're not competant. When it comes to fire; don't give advise based on what you think you know only on what you actually DO know. Similarly, don't accept advise from anyone unless you are satisfied that they are competant in that field. Fire alarm engineers should work on fire alarms and electricians should work on 240v wiring. I'm sure I could rewire a house and it would all work, but I don't know the regs and a decent electrician would probably rip it apart. (I'm a fire alarm engineer)
mcelec Posted April 19, 2005 Posted April 19, 2005 Here here that man.Every individual must be competant to do the job. If you don't know the standards then you're not competant. When it comes to fire; don't give advise based on what you think you know only on what you actually DO know. Similarly, don't accept advise from anyone unless you are satisfied that they are competant in that field. Fire alarm engineers should work on fire alarms and electricians should work on 240v wiring. I'm sure I could rewire a house and it would all work, but I don't know the regs and a decent electrician would probably rip it apart. (I'm a fire alarm engineer) 40972[/snapback] you say that every individual should be competent to do the job but then you make a comment that suggests electricians are not competent to install a fire alarm system? surely an electrician who is familiar with the standards is far more competent than an engineer only familiar with fire alarms, im an electrician but im also a fire alarm engineer, but if anyones competency need questioning it is alarm engineers who assume they know what they need to do when it comes to adding fused spurs to power the systems they have installed because most of the time they have neither the technical qualifications or the knowledge of bs7671 to be able to carry this work out. (oh one more thing, i think you will find that the nominal voltage Uo of low voltage mains in the uk is 230Vac)
Guest Cerberus NI Posted April 19, 2005 Posted April 19, 2005 Just picked up on this topic but ALL communication cables (by that I mean the detection zones,sounder circuits,auxillary outputs and links to intuder panels) and mains supplies/power supply outputs must be wired in fire proof cable.No plastic choccie blocks either (as mentioned earlier, must be ceramic) and no P clips - must be fixed using plastic coated copper clips.Oh,and no more tie wrapping to cable trays or down conduits!!!
secboy Posted April 20, 2005 Posted April 20, 2005 Just picked up on this topic but ALL communication cables (by that I mean the detection zones,sounder circuits,auxillary outputs and links to intuder panels) and mains supplies/power supply outputs must be wired in fire proof cable.No plastic choccie blocks either (as mentioned earlier, must be ceramic) and no P clips - must be fixed using plastic coated copper clips.Oh,and no more tie wrapping to cable trays or down conduits!!! 49429[/snapback] Good input guys, thanks for the pro opinion cerb! regards Paul [anyone know why my two applications to trade have fallen on stoney ground??]
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