I'm rebuilding after a fire, and I need to know if the new smoke/co detectors need to be hard wired.

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    You should contact your local building inspector to be sure, but I'm fairly sure they must be hardwired in all new construction in the US (or most areas anyway). – Tester101 Dec 6 '13 at 14:26
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    Since you're rebuilding after a fire, I think the question should be "why not" rather than "am I required". – BMitch Dec 6 '13 at 14:48
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    And since you're rebuilding after a fire, you might as well look at installing fire sprinklers too - they won't prevent a fire from starting, but can keep the fire damage localized. Installing during new construction or major remodel is much cheaper than retrofitting later. – Johnny Dec 6 '13 at 16:59

According to the New Jersey Department of Community Affairs, New Jersey has adopted the 2009 version of International Residential Code (at the time of writing). The 2009 IRC has this to say...

International Residential Code 2009

Chapter 3 - Building and Planning

Section R314 - Smoke Alarms

R314.4 Power source. Smoke alarms shall receive their primary power from the building wiring when such wiring is served from a commercial source, and when primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection. Smoke alarms shall be interconnected.


1. Smoke alarms shall be permitted to be battery operated when installed in buildings without commercial power.

2. Interconnection and hard-wiring of smoke alarms in existing areas shall not be required where the alterations or repairs do not result in the removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available which could provide access for hard wiring and interconnection without the removal of interior finishes.

Which means that not only do the smoke alarms have to be hardwired, they also have to have a backup battery and be interconnected. Unless of course you are generating your own power, or you're retrofitting a home and hardwiring is impracticable.

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