24v cable

Electrical estimator here. I sometime see 24v wiring( not fire alarm cable) for modules/relays. I’m never 100% clear WHAT devices require it and WHEN 24v cable is needed. Any help would be great. Thanks

Any vital parts of a fire alarm system such as a smoke detector may require special fire alarm cable.

This video may help:

Thanks to @FireAlarmDude5967 for this video.

Another piece of advice, you can put this in the “Fire Alarm Help” section, it will make life easier.


Jeez! 7 years!

That’s going to vary depending on system manufacturer and device. Some Simplex duct smoke detectors require separate 24vdc, as well as some beam smoke detectors, Honeywell/Notifier control modules, release modules, door holders, 4-wire smoke detectors and auxiliary relays.

Juz the Jeez! (davemadson jokes)

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