BBB Business Review
Smoke Detectors

Smoke Detectors

Two wire and four wire varieties can be used with any hardwired alarm system. Two wire smokes use just two wires for data and power and must all be ran on the same run. Four wire smokes use separate two wire pairs for power and zone data and can be separated on their own zones.

More About Smoke Detectors

All of the hardwire alarm systems we sell can accept either 2 wire or 4 wire type, but there are some things to keep in mind when making this decision. A couple of things are:

1. Generally speaking, you are limited to a maximum of about 8 two wire smokes per system (exact amount is determined by loop resistance), four wire type allow you to have many times this amount, only limited by the current available from the board or power supply.

2. Two wire type offer full supervision of the line between the panel and smoke, whereas four wire type only supervise the detection circuit by default. Two wire type are the latest technology, however four wire type are the universal standard and should be used when in doubt.

There are different styles of two wire and four wire smoke detectors. If you need a simple smoke detector then we carry those in the 2W-B and 4W-B models. There are also the 2WT-B and 4WT-B models which are a combination smoke and heat detector. Then there's the 2WTA-B and 4WTA-B models which are smoke detectors with combination heat detector with a built-in sounder for local notification of emergency.

We also carry the System Sensor COSMO2W and COSMO4W model smoke detector combined with a carbon monoxide sensor. These smoke / CO combination units use an intermediary module that goes between the detector and the panel called the COSMOD2W and COSMOD4W respectively. The modules separate out the smoke and CO loops before going to the panel and have separate runs for power. 

Not only do we carry the two wire and four wire smoke detectors but we also carry accessories for them. For the smoke detectors that contain sounders we carry the System Sensor RRS-MOD Reversing Relay and the DSC PRM4W. These relays will set off sounders in all the other smokes in the line if one is triggered.

We also feature power supervision relay models DSC RM-1, DSC RM-2, and SYS-EOLR1. These supervise the power of smokes and will make you away if the smokes lose power or the line is cut.

And lastly, we carry canned smoke for you to use to test your smokes after installing them.