Letter Re: Power Failure Alarms

I need your advice. I am worried about power failures, and even EMP while I’m sleeping. This could take out my security system, and leave my family vulnerable. Is there any sort of device that’ll alert me if the power goes out? Thanks, – Nolan S.

JWR Replies: There are fairly inexpensive commercially-made plug-in power failure alarms available via mail order for under $15. (Or under $20 each at larger home improvement stores.) I recommend buying one for each bedroom, and one for your generator house. (The 86 dB alarm is not loud enough to be heard from far away, but having a light on for you at your generator house on a dark, snowy night is a very welcome sight!) Needless to say, these are a must for sleep apnea patients that use a CPAP machine, or for anyone else that uses other 120 VAC medical devices for chronic health issues. These alarms work fine for houses with grid power, or for houses with backup generators. (The alarm will trip before an auto-start backup generator kicks in.) If you have a grid-tied alternative energy system, you would of course need to plug one of these into an outlet that is exclusively grid-powered. If you live off-grid, you won’t have any way of knowing, but then again, if your level of concern for such an event will probably be minimal.

If your specific concern is a power failure in the event of EMP, then you could always wire up a battery-powered traditional buzzer with a “normally closed” relay. (When the grid power is disconnected, the relay closes, and energizes the DC buzzer circuit.) That is 1920s-era technology that would be EMP proof.