Smoke Detectors

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Re: Smoke Detectors

allen totally agree. Aint never been afraid to ask an oldtimer for tips. Or give a greenie tips that some old timer gave me. J walker you got me pegged. Ill probaly stat through Jan than look elsewheres. Probaly go back to condos. Where I hope to find opportunity to run a rough crew. Too many rough crews on condos are slow as molases in the winter
 
Re: Smoke Detectors

I'd like to point out that the 3VA/sq.ft. is specified for lighting loads, and that these days, we use a lot more power in bedrooms than just for lighting.

What I do these days is use a 20a circuit for bedroom receptacles, using the ('99 NEC) required AFCI breaker, and a separate 15a circuit for lighting.

Even when we start using the '02 NEC, I will still separate receptacles and lighting in bedrooms and most other areas. IMHO, this affords better performance.

In other words, turning on the bedroom TV won't cause an overhead light to dim, and reduces electrical noise in electronics from fans and dimmers, to a degree.
 
Re: Smoke Detectors

Smoke detectors is placed 36" away from air condition/heating supply registers. will that be the same for return air registers?
 
Re: Smoke Detectors

roger, You said a "mouthfull" there about experience and who has the MOTIVATION to take the "TEST" Anyway, back to AFCI. I run a "home run" for each bedroom, not for loads, just easier to troubleshoot in the future "if they have a problem" less furniture to move and easier to isolate a problem. Also,with a computer, TV, and other Inductive loads "Kids today" it may not be a bad idea to "Home Run" each bedroom. Not code, just My thoughts.
 
Re: Smoke Detectors

I'm not one to complain, but how did we go from circuiting bedrooms to who qualifies for an AARP membership?

The 3VA/sq ft is for determining the number of circuits required. As Charlie said there is no requirement to use the dimensions of the room to circuit it. Figure out the number of circuits and divide them up any way that you want. The NEC requires nothing further.

[ December 31, 2005, 05:13 PM: Message edited by: infinity ]
 
Re: Smoke Detectors

AARP? I do hope that was not in response to my reply. I tried to give an educated reply from one licensed electrician to another regarding helpers and the real world on running bedroom circuits.
 
Re: Smoke Detectors

The code states
In spaces served by air-handling systems, detectors shall not be located where airflow prevents operation of the detectors.
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An editorial (not code) of the code states: Detectors should not be located in a direct airflow or closer than 1 m (3 ft) from an air supply diffuser or return air opening. Supply or return sources larger than those commonly found in residential and small commercial establishments can require greater clearance to smoke detectors. Similarly, smoke detectors should be located farther away from high velocity air supplies.
 
Re: Smoke Detectors

In the 2005 cycle 220.12 tells us to use 3 volt-amperes per square foot. Now let?s use this to load the circuit.

15 amperes times 120 volts gives us 1800 volt-amperes. Divide these 1800 volt-amperes by 3 watts per square foot and it will give you 600 square feet of space that can be wired with this circuit.
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JW, with all due respect to your Age, wisdom, experience and so forth and so on, may I add that that is a reasonable method, but that particular code is for sizing the service of the building, not sizing the branch circuit size or loading. For my own work, I do not like to mix lights and receptacle outlets together, I use #14 for lights, I use #12 for receptacle outlets, I generally swag about 2 amps load per outlet and count em up and stop at around 80 per cent of the breaker rating assuming all receptacles are loaded to the 2 amps at the same time( kitchen or laundry, bath loads excluded from this). Real world loading is much different. The one receptacle supplying Mrs. Jones vacume cleaner at the moment draws about 14 amps and the rest of the outlets in the entire circuit have a combined load of maybe 2 amps with the digital clock radio's on them. Then Mrs Jones, turns off the vacume and uses the computer in the bedroom for 15 minutes and now the load is around 4 amps total. Then she takes a nap and the load is back to 2 amps, because the majority of those receptacle outlets are behind furniture and never get any use at all. Next door at Mrs Smith's house the situation is pretty much the same, except she has gone out and bought 4 window ac units (12,000 btu) and has them all plugged into the same circuit because the guy at Sears was not really trained in electrical and showed her the plug end when she bought them and said "see- they fit into a regular plug. Mrs Smith has to reset her breakers alot of the time. One day her house is going to catch fire from the overloading on her 3 watts per square foot wired house. What is my point? It is that the code does not specify the method, and we can't really control what the circuit gets loaded up to if it has receptacles on it, and I believe that is why the code does not try to limit the number of outlets on a general purpose circuit in a dwelling.
 
Re: Smoke Detectors

In the counties I usually work in, smoke detector circuits have to be all interconnected with nothing else on the circuit.

Paul
 
Re: Smoke Detectors

macmikeman,
Next door at Mrs Smith's house the situation is pretty much the same, except she has gone out and bought 4 window ac units (12,000 btu) and has them all plugged into the same circuit because the guy at Sears was not really trained in electrical and showed her the plug end when she bought them and said "see- they fit into a regular plug. Mrs Smith has to reset her breakers alot of the time. One day her house is going to catch fire from the overloading on her 3 watts per square foot wired house.
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If the breaker is opening the circuit as it should, why is there going to be a fire?
Don
 
Re: Smoke Detectors

In the counties I usually work in, smoke detector circuits have to be all interconnected with nothing else on the circuit.
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Thanks Paul,
I have been wondering if I was completely mistaken in wiring smoke detectors on a circuit all by themselves. I am not sure if it is State or County driven. I am thinking State, but maybe not.
 
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