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Thread: Fire alarm NAC circuits

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    Fire alarm NAC circuits

    I've come across strobes and horn/strobes speced to be wired alternating circuits..like a/b/a/b ...anyone familiar with this?

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    came across a speaker strobe that was labeled A/V throughout the drawings, never figured out why it wasn't labeled S/S.
    jerryalan

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    Quote Originally Posted by jerryalan View Post
    came across a speaker strobe that was labeled A/V throughout the drawings, never figured out why it wasn't labeled S/S.
    Cause it is an Audio/Visual device?

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    Quote Originally Posted by GoldDigger View Post
    Cause it is an Audio/Visual device?
    Yes, that exactly.

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    Quote Originally Posted by mstrlucky74 View Post
    I've come across strobes and horn/strobes speced to be wired alternating circuits..like a/b/a/b ...anyone familiar with this?
    It was popular in NYC, or so I've been told. The Port Authority of NY and NJ has added a design guideline for fire alarm systems for the LaGuardia Terminal B project that says you can't lose more than 60% of the notification appliances in a space if there is a circuit failure. There is nothing in NFPA 72, the NYC building code or Appendix Q thereto that requires "A/B" circuiting. It may show up in a specification, or there may be an AHJ who has a "shirt-pocket" rule.

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    Quote Originally Posted by gadfly56 View Post
    It was popular in NYC, or so I've been told. The Port Authority of NY and NJ has added a design guideline for fire alarm systems for the LaGuardia Terminal B project that says you can't lose more than 60% of the notification appliances in a space if there is a circuit failure. There is nothing in NFPA 72, the NYC building code or Appendix Q thereto that requires "A/B" circuiting. It may show up in a specification, or there may be an AHJ who has a "shirt-pocket" rule.
    Gad just revisited this thread. It does look like NYC code requires alternating circuits for notification.
    Attached Images Attached Images

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    I've seen it as a job spec but not written into any official local code.

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    Quote Originally Posted by mstrlucky74 View Post
    Gad just revisited this thread. It does look like NYC code requires alternating circuits for notification.
    Where did you find your pages? It looks like it's out of the formal wording to amend a code, the clue being that all the words are underlined.

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