Smoke Detector/Alarm In Series With A Light At The End

memetic

I came into a situation where someone had setup smoke detectors in series starting in the basement and ending on the other end of the house on the second floor. Then, someone (maybe the same person?) took a line off the end and ran it to a switch to power a light. I don't care if it is to code, but is this safe? I don't want to touch this situation at all, unless there is serious risk of damage, injury or death. Thanks.

480sparky

Smoke detectors in series?

I doubt it, especially if you're talking about plain-jane 120v resi smokes. In series, they will not function. I think you mean in parallel.

If so, unless there's a local Code that requires they be on a seperate circuit, there's no NEC violation.

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memetic

Good to know. I wouldn't feel right not letting them know there may be a danger (but, I really don't want to get involved with this electrical issue).

Re: series vs parallel. I don't know actually. I know that the 14g wire starts at the box, goes to the 1st smoke, then the 2nd, then the 3rd, and ends at the light on a switch.

Thanks

480sparky

I'll bet it's parallel. I can't think of any house wiring that would be in series.

__________________
Site : the area or exact plot of ground on which anything is, has been, or is to be located.
Sight : The power or faculty of seeing; perception of objects by use of the eyes; vision.
Cite : To mention in support, proof, or confirmation; refer to as an example.

KennMacMoragh

He means parallel, I've heard people say that before. If you have three lights that turn on together or something, they'll say it's in series, but they don't know what it means.

memetic

Oh yes, of course, parallel. I meant that the detectors go from one to the next and nothing branches out from anything - except at the very end being the light (and switch). I should have realized what you meant - sorry for the brain fart.

KennMacMoragh

Yeah, first thing they teach in electrical is the difference between series and parallel, series circuit (left-hand side). Just think, Christmas lights are in series, probably the only series circuit you'll find in a house.

Zinsco

To answer your question the code permits this and it is safe assuming it was done properly. I'll run 3 or 4 smoke detectors in a chain like that then feed 2 entire bedrooms with the circuit.
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Magnettica

Zinsco, do you wire your smoke detector series circuits normally open or normally closed?

I know if you wired my house like that and the 2 bedrooms didn't work because the damn smoke detectors were activated I'd be pissed.

But then again I think you're only jerking everyones chain when you post anyway.

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Zinsco

Well this is a case where I'm serious. When you say "normally open" or "normally closed" it is clear *you're* talking about a commercial fire alarm system. I suppose to use the proper terminology I'm talking about a hard wired "smoke alarm" you buy at Home Depot for $12.

fireguy

I like to see the smoke alarms wired like you do. There is less chance of the breaker to the smokes being turned off when a smoke goes into alarm. http://www.oregon.gov/OSP/SFM/docs/C...Q-A_Sheet2.pdf