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why do hard wired smoke detectors not have battery back up?
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- ELECTRIC LESLv 67 years agoFavourite answer
Most do, and all the ones I have fitted have a battery backup. I can see no point in fitting ones without a backup as they will not work if the mains supply fails.
Source(s): Retired electrician - 7 years ago
Most hard wired fire alarm systems do have battery back up, via a UPS, (uninterrupted power supply), or via an emergency supply, or integral battery. It would be senseless installing otherwise.
A power failure would otherwise render the whole installation vulnerable.
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