Security & Fire Protection Systems/Smoke Detectors


I am in the process of selling my home and had the fire alarm/carbon monoxide inspection. I was told I needed photelectricd sensors. My original fire alarms are hardwired. The only photeclectric sensor I could find is battary operated. Can I install these in place of the hardwired detectors?

Hello Roxanne, and thanks for your question.

If you have hardwired detectors in place, and I'm assuming they are ionization detectors, there should be no major issues in replacing them with photoelectric detectors. That's because the wiring for these is pretty consistent; two wires for the AC power, and a third wired to interconnect the detectors so that when one alarms, all the other detectors sound the alarm.

But while the wiring in place will be compatible with whichever photoelectric devices you choose, there are two other factors to consider. First, you'll likely have to replace the base of each detector. That's the part that is fastened to the ceiling, and the detector attaches to it.

Second, for the electrical connections, there's a wiring harness. That's merely three wires connected to a plug that connects to the detector. If the plug isn't the same in the old detectors as in the new, you'll have to replace that as well.

If you can tell me the make and model of the detectors you have now, I may be able to recommend a replacement that uses the same wiring harness. Most detectors are released from the base by a quarter turn counter-clockwise. The make and model number will be on the top of the detector.

If you're not handy with hand tools, or are unsure of being able to replace the detectors yourself, any competent handyman can do the job for you.

I hope this helps, and please write again if you have any follow-up questions.

Best Regards,


Security & Fire Protection Systems

All Answers

Answers by Expert:

Ask Experts


Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


©2017 All rights reserved.