2 wire or 4 wire smokes
- Thread starter blackbelt
- Start date
upstatemike
Senior Member
I have 2-wire now but will be switching to 4-wire because most panels do not support very many 2-wire zones. Wish I had wired for 4-wire to start with! Also remember to homerun both the feed and return to smoke detectors you expect will share a zone with other smoke detectors.
Since many panels only have one or two 2 wire smoke zones you would probably be better off with 4 wire detectors since you are homerunning everything. The M1 only has one 2 wire zone. It can handle up to 20 detectors but they have to be series parralled and have an EOL Resistor for supervision.
Personally I like 4 wire detectors for flexibility.
I'm a little fuzzy on the "Clean Me" feature.....what is it? Also, I will have approximately 14 - 16 Detectors that will be homerunned. On homerunning a zone, do you wire to one smoke, then another, then homerun to the equipment closet? Besides cost of wire, why wouldnt I want to homerun each individual detector the the Elk panel? I would prefer that when the smokes go off and alert the fire dept., for it to also state the room it originated in. This is why I didnt know if it was feasable to homerun all the smokes individually. Also, would each individual smoke require a power supervision relay at the end? This is new construction. Your thoughts are appreciated.
If you want to individually annunciate which detector is oging off you have to go with the 4 wire detectors.
The System Sensor 2 wire smokes that are approved by ELK will send a signal to the M1. The keypad will read "clean me smoke" and then you look at the smoke led's to determine which one needs cleaning. My opinion is that if a smoke alarm goes off, get everyone safely out of the house, no matter where the fire is. In my situation the fire department would be here before I could go back in to fight the fire.
Steve
Senior Member
It's really a tradeoff and depends on what you really want. 2 wire is wired daisy chain to each other and requires 1 EOL and hooks to zone 16. You can get the clean me feature, but you lose zoning. 4 wire you need an extra Elk expansion card for that many zones and you need a relay for each one as well. It will cost you more but you can get full zoning. So its really a personal choice - both 2 and 4 wire detectors are essentially the same quality.
You only need one relay if you daisy-chain the power. (You can get the smoke with a relay built-in also)
Brian
Many smokes have a feature which flashes an LED on the smoke when it has been tripped, so even if many go to one zone, you can determine the troublemaker. When you set your alarm the next time, the power to the smokes is inturrupted, and this resets their tripped condition, so be sure to check for the LED BEFORE setting the alarm on again after a trip.
