Question:
I have a question about 2 vs. 4 wire smoke detectors and placing them on multiple zones. I'm going to install a Caddx N8e system and would like to define zones for each smoke. I'm going to have a pretty large home and plan about 8 main smoke detectors.

My question is for me to do this I believe I need to have 4 wire smoke detectors. This way it will allow me to have each one on their own zone and power them from the panel's aux outputs. Is this correct? I don't think I can use 2 wire because the zones can't power them and if I use the smoke + / - it only would give me 1 zone for all smoke detectors.

Answer: -if you want to know exactly which smoke detector tirgger first incase of fire alarm then you have to use 4 wire smoke detectors (mostly NO/EOL). If you connect 2 wire detectors you will only have one zone. I prefer the second method (2 wire) cause its very simple, easy to install and more reliable.

-First, both two and four wire smoke detectors are equally reliable. Four wire detectors can be used on any system but two wire detectors must be listed for use on specific control panels. There is also a limit to the number of two wire detectors that may be installed on a specific control panel.

You MUST use the end of line (EOL) resistor on all fire alarm circuits. This is law. NFPA-72 requires that all fire alarm circuits be supervised. This code is adopted in virtually every city and state in the nation. I don't know anywhere in the Unites States where this does not apply. When using a four wire smoke detector you also must use a end of line power supervision relay. This is also required for supervision of the smoke detector circuit.

One thing you should note, smoke detectors have a memory light. If you want to know which one(s) tripped all you have to do is look at the detectors before you reset them. This will not tell you which one tripped first but will tell you which one(s) have tripped.