I am planning a new construction Elk M1 project. Have read through the existing threads related to smoke alarm wiring, and am still confused. Would anyone be willing to describe the best plan for connecting 9 smoke alarms (looking for recommendation on 2-wire vs. 4-wire) to the M1 panel so that if any one of them goes off the system can alert the homeowner via speaker and phone call? Thanks!
Elk M1 Smokes Planning
- Thread starter jmistler
- Start date
upstatemike
Senior Member
It depends on what you want to accomplish with your smoke detectors. Some folks just want straight life safety and don't need to know which smoke detector set off the alarm so they put all their smoke detectors on a single zone. 2-wire is definitely the way to go for that application. Others want a voice alert to say where the fire is and perhaps do some automation functions specific to that area in the event of a fire so they need multiple fire zones. 4-wire is usually going to be the easiest way to do that with an Elk M1 since there is only 1 zone that supports 2-wire smokes natively. There are also Elk wireless smokes to consider. You can also use generic 120V smokes if local codes require them and have a gizmo listen for the smoke detector alarm and trigger an Elk Zone for the speaker and phone call part. And then there is the question of CO detection which I believe is now a requirement in new homes.
Thank you for that higher level clarification— very helpful.
Page 6 of the M1 Installation Manual does not give clear instructions on wiring for either scenario. Could you help clarify that for me?
Regarding 2-Wire Smokes:
1. Is a standard 18/2 cable the correct choice?
2. How does the daisy chain wire up: Zone16—> SmokeAlarm#1—> Alarm#2—> Alarm#3—> Termination how?
Regarding 4-Wire Smokes:
1. What cable(s) is correct: (2) 18/2, 18/4, something else?
2. How does the wiring work?
Zone1—> SmokeAlarm#1—> +SAUX
Zone2—> SmokeAlarm#2—> +SAUX
Zone3—> SmokeAlarm#3—> +SAUX
With only 1 +SAUX terminal, how do multiple 4-wire smokes connect back to the panel? Clearly, I’m missing some key concepts here. Thanks.
Page 6 of the M1 Installation Manual does not give clear instructions on wiring for either scenario. Could you help clarify that for me?
Regarding 2-Wire Smokes:
1. Is a standard 18/2 cable the correct choice?
2. How does the daisy chain wire up: Zone16—> SmokeAlarm#1—> Alarm#2—> Alarm#3—> Termination how?
Regarding 4-Wire Smokes:
1. What cable(s) is correct: (2) 18/2, 18/4, something else?
2. How does the wiring work?
Zone1—> SmokeAlarm#1—> +SAUX
Zone2—> SmokeAlarm#2—> +SAUX
Zone3—> SmokeAlarm#3—> +SAUX
With only 1 +SAUX terminal, how do multiple 4-wire smokes connect back to the panel? Clearly, I’m missing some key concepts here. Thanks.
jmistler said:
Use 18/2 for 2-wire smokes and 18/4 for 4-wire smokes. But you should use fire-rated cable, certified as type FPL or better.
Both 2-wire and 4-wire smokes should be wired in a daisy chain. The cable from the panel should run to the first smoke, then on to the second, and so on. With 4-wire smokes, you will need a power supervision relay (i.e. and EOLR) at the last smoke in the chain.
If you put 4-wire smokes on multiple zones, it gets quite complicated. Each zone will need it's own EOLR. In order to have all smokes sound an alarm, you will need reversing relays for each zone that will reverse power polarity in order to cause the other, non-alarm zones to sound.
If you're using a power supply other than SAUX, you'll also need a relay to interrupt power to all the smokes in order to reset them after an alarm condition.
If you have all your 4-wire smokes in a single daisy chain on one zone, you'll only have one pair of wires running to SAUX. But if you have them on multiple zones, then you'll have multiple pairs that require power from SAUX. In that case, wire nut them all together and run a pigtail to the SAUX terminals.
My opinion is that the extra complexity required for multiple zones of 4-wire smokes isn't worth it in most situations. Just go with 2-wire smokes or 2-wire smokes on a single zone and keep it simple.
