I'm doing a small fire alarm job, and the technician from Grinnell told me that the colour coding used does not matter, as long as the signal gets back to the panel. This doesn't sound right...I am using 5 conductor armoured FAS cable (LVT with red jacket) With the following colouring scheme inside it. red/black/blue/brown/green.
Obviously I have established that green is ground LOL But what colours constitute a pair? Is it Red/Black to device and Brown/Blue return to panel or EOL?
I did some witring on an addressable system at a retirement home and used black / red as my loop, ( all was 3-conductor "FAS" cable) the only exception was where a single 5-conductor cable was used as a drop to a pullstation or smoke detector, the red / black pair was connected and deemed "FROM PANEL" and the blue / brown was connected deemed " TO PANEL" with the red/brown being Positive and the blue / black being the negitive conductors.. Not that it matters much but in this way with everything being uniform like that I could break the loop at any point while troubleshooting and know what pair was coming from the panel and what was going back to the panel..
The other question I had was...In some places it was almost impossible to fish both cables to each device, so since I was using 5 wire FAS i ran three cables into one box and branched off one to the device that was hard to fish to. As long as I wire this as a loop is this still OK? Also I do know the difference between FAS and LVT i just used it as a comparison since they are similar in construction (minus the armour). Sorry bout the confusion! Thanks for all your help! -Stefan
Yes you are right. You can do that as long as it is a continuous loop. I am sure that you already know that you are not allowed to T-Tap for non-addressable systems so as long as the loop is maintained and the system can supervise the entire circuit you are good to go.
There is no set colour coding for FAS cable, I have had this discusion many times. It is generaly accepted that red-black is one pair with red being positive and black negative, the second pair is brown - blue with brown being positive and blue negative. Over the years cable manufacturers have changed the colours a few times, they always put red-black-blue and the fourth colour has been yellow, green,brown or tan.It would make sense to actually put this coding into section 32 of the CEC. When I install fire alarms I always make the red black pair the supply pair and the blue brown as a return. warning though there is on cable manufacturer that makes a FAS cable where the brown is almost black and if you are not carefull it is easy to cross the pair.