How many smoke detectors?

The NEC doesn't really talk about smoke detectors (other than some info on how they are powered). The requirement for smoke detectors as far as NFPA is in their standard NFPA 72. However, usually it's the local building code that mandates their placement.

The sad fact is that most home inspectors are idiots.

The NEC doesn't really talk about smoke detectors (other than some info on how they are powered). The requirement for smoke detectors as far as NFPA is in their standard NFPA 72. However, usually it's the local building code that mandates their placement.

The sad fact is that most home inspectors are idiots.

Going from memory, I believe there are 8. Its possible 10. Its a ranch 3 bedroom, 2 bath with bonus room above garage.

Is replacing the detectors an easy task? I have replaced light fixtures numerous times, but never dectors.

It's a great thing for the manufaturers of smoke detectors: They get to sell replacements - and it's a CYA.

The first thing the insurance company will do is go after anyone it can. So the smoke detector people do a CYA and say they should be replaced after 10 years.

Why not 9 years? Why not 11 years? It's just an arbitrary number.

Same thing has been said for airbags in cars.

It is possible that new detectors from the same manufacturer will essentially plug in to the existing bases. Explore that possibility.

I just bought First Alert 3120B wired dual mode (both photoelectric and ionization) smoke detectors to upgrade my house and it cost $96 for a 3 pack. They came with a plug that you can wire onto any existing 120 volt box. Once you have the plug installed in the box the detector just plugs in and snaps onto the mounting ring.

The wiring is simple (black and white for power, red for signaling), and it should directly replace an existing detector. It is similar to replacing a light.

If you have 10 detectors you would spend about $330 for the hardware, and it would take you or an electrician a couple of hours to swap out 10 detectors.

Bruce

Most smoke detectors use americium-241 as their source. Some early models used radium-226, and commercial smoke detectors and some residential units used nickel-63.

Some folks think that it become ineffective after 10 years. That doesn't seem to be the case.

The half life of Am-241 is 241 years. The amount in the ionization smoke detectors is very small. You'll get more radiation from eating a banana.

Here is a link that might be useful: Smoke Detector background

This post was edited by jreagan on Sat, Mar 29, 14 at 9:29

This "electrician" is a sham. There is NO "NEC 2008 smoke detector code".
He is trying to sell you something you don't necessarily need.

I will say, replacing SD's every 10-15 years IS a good idea (as per manufacturer's recommendations), but there is ABSOLUTELY NOTHING in the NEC mandating it. Especially nothing that has changed in the last 3 cycles.

"If you have 10 detectors you would spend about $330 for the hardware, and it would take you or an electrician a couple of hours to swap out 10 detectors."

That would put the price for complete installation, with warranty, by a legitimate electrical contractor at least $650. Craigslist hack would price it about $360 and a case of beer.

If its truly as simple as plugging in the same manufacturer brand I can do that. I have swapped put over 50 light fixtures in last five years. I checked at my current house (1984) and if the "new house" (2000) is similar I feel confident in doing so. I just thought maybe something between year 2000 and 2008 changed requiring new wiring. If its just a matter of replacing the detectors I will tackle myself and save $300 plus.

I have the same type of wired setup as you do, and I just replaced one that was malfunctioning for $15 dollars. Two screws to loosen to remove the old unit and substitute the new updated version; the replacement just plugged in to the existing harness. Do it yourself....

Thanks all. Next time I am at the house I will check mfg etc, but am planning to change them out my self and add a Carbon Monoxide detector as its gas heat and water and fp.