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Thread: Hard wired smoke detectors

  1. #1
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    Hard wired smoke detectors

    What are the wiring requirements for hard-wired smoke detectors? Must they be wired on a dedicated circuit to the panelboard, or must they be wired on a kitchen light circuit?

  2. #2
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    Re: Hard wired smoke detectors

    They must be wired to the pantry light.

    Chris

  3. #3
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    Re: Hard wired smoke detectors

    Originally posted by raider1:P.S. They also need to be on an AFCI protected circuit.
    I suspect you are just trying to pull someone's leg. They don't have to be on an AFCI circuit unless they share that circuit with one or more bedroom outlets.

    There are a couple rules that forbid any other outlets from being on the same circuit. One relates to the "Small Appliance" circuits. Another relates to receptacle circuits in bathrooms.

    As long as you don't violate any of those requirements, you can power the detectors however you wish.
    Charles E. Beck, P.E., Seattle
    Comments based on 2008 NEC unless otherwise noted.

  4. #4
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    Re: Hard wired smoke detectors

    Charlie, if the local code requires smoke detectors in every bedroom, then they need to be protected by an AFCI.

  5. #5
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    Re: Hard wired smoke detectors

    I was trying to be funny, sorry. :o

    The reference to a AFCI was on an assumption that this is new construction. In a new home a hard wired smoke detector is required in each bedroom, and outside of the bedroom. These smokes need to be interconnected, which means any other smokes will be on the same circuit and therefore be part of a circuit with outlets in a bedroom. 210.12 (B) is the code reference to which I am referring.

    In Utah we use the IRC which is where the smoke detector requirements are from.

    The original poster might have been talking about a smoke detector in a remodel which might not meet the same requirements for the interconnect.

    Chris

  6. #6
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    Re: Hard wired smoke detectors

    fremont's openning post asks about the kitchen lighting circuit as a source of power for hard wired smoke detectors.

    The important word I note is that detectors is plural. I assume, then, that the detectors are 125 Volt and that the lighting circuit is 15 or 20 Amps.

    As long as none of the smoke detector openings are installed inside bedrooms, the NEC allows this, with no comment.

    However, if one of the smoke detectors is mounted on an opening inside a bedroom, the outlet that the smoke is connected to must be AFCI protected, per NEC 210.12(B).

    Local ordinance or State ruling may exist that waives smoke detectors from the requirements of NEC 210.12.
    Another Al in Minnesota

  7. #7
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    Re: Hard wired smoke detectors

    Originally posted by peter d: Charlie, if the local code requires smoke detectors in every bedroom, then they need to be protected by an AFCI.
    The ones in the bedroom do, but the ones in the kitchen do not need to be on the same circuit. I agree with the way Al described the distinction.
    Charles E. Beck, P.E., Seattle
    Comments based on 2008 NEC unless otherwise noted.

  8. #8
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    Re: Hard wired smoke detectors

    I agree that local and state amendments might change the NEC and other building code requirements. The IRC is pretty clear that all the smoke detectors be interconnected.

    That said the smoke detectors that I have wired interconnect with a 4 wire system (1 ungrounded conductor, 1 grounded conductor, and one interconnect wire, as well as a EGC). These systems are only on one circuit, hence the requirement for AFCI protection.

    Chris

  9. #9
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    Re: Hard wired smoke detectors

    I would like to add that not all jurisdictions are under the '02 or '05 code cycle, so the "all outlets in bedrooms must be on AFCI-protected circuits" rule may not apply.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  10. #10
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    Re: Hard wired smoke detectors

    LarryFine makes a good point.

    Each area can have different changes, adoptions, and editions of codes enforced. That can make it hard to make a statement like I did in my earlier post.

    Chris

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