Reliance Controls PowerBack Utility Power Return Alert-THP108 - The Home Depot
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Reliance Controls

Model # THP108

Internet # 202216506

PowerBack Utility Power Return Alert

Reliance Controls PowerBack Utility Power Return Alert

This item has been discontinued.
The Home Depot no longer carries this specific product.

$39.99 / each


Model # THP108

Internet # 202216506

The PowerBack is intended to be installed on a manual transfer panel or generator-ready load center. During a power outage, when the main breaker has been turned off to allow the generator to provide emergency power to the panel, the PowerBack can be activated and will emit a pulsing 105dB alarm when the power outage ends and utility power is again available. The PowerBack installs in a 1/2 trade size knockout in the panel within 20 in. of one of the utility hot legs. It includes an eight-inch current sensing antennae at the end of a 22 in. jacked lead. When wrapped around one of the hot legs to the main circuit breaker, the antennae will detect the returning utility current and activate the sonic alert.

  • Lights for "System Armed" and "Low Battery"
  • 9 Volt battery not included
  • UL Listed
  • 5 year warranty

Info & Guides

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Electrical Product Type 
Alarm Sensor/Control Center 
Load Center Type 
Temporary Power 
Mounting type 
Number of Phases 
Product Series 
Reliance Controls 
Product Weight (lb.) 
0.5 lb 
Warranty / Certifications
Manufacturer Warranty 
5 years 


Rated 4.3 out of 5 by 30 reviewers.
Rated 5.0 out of 5.0 by Great Value ! Easy to install and works great. I did not have room to mount on top of the power panel as suggested due to all the wires, so I mounted mine on a 3/4" PVC LB that I mounted on the side of my power panel at a knockout within easy reach. When activated by a power return it is VERY LOUD and can be heard throughout the house. So loud it almost hurts while getting to it to turn it off. I used to watch for neighbor's lights to come back on, now I know immediately when I can switch back from the generator. December 10, 2013
Rated 5.0 out of 5.0 by Works as advertised! Unit works great. Wrap around hot leg with electrical tape. This gives a tight fit. Sonalert is loud and I can hear it well at all locations. Added benefit is a magnet is on the back of the unit so you can place it on the box if the box is recessed. Good pricepoint as well. June 18, 2013
Rated 5.0 out of 5.0 by Reliable and loud as advertised Connecting device is quite simple. I used zip ties to secure the lead to one of the 2 hot wires coming in from the power company. Sound is plenty loud; I could hear from inside house furthest point to device in garage. Mounted right above power panel. Used wall plate to conceal wiring and double face tape to adhere device to wall plate for "cosmetic appearance". Wish I ordered sooner since I connect my power generator directly to power panel through double breakers. April 8, 2014
Rated 5.0 out of 5.0 by Simple to install and does what it says For other reviews which say this is not loud enough I think they must have a high tolerance for loud noise. When I set this thing off the alarm blew my head off so I was suprised that many think that it is not loud enough to hear. Of course if you have a huge house and the panel is very far away I can see that it may be a problem hearing the alarm but you have to be realistic. I found this unit as loud as a smoke alarm. At least to me. Installation was a breeze and so far it seems to work. I won't know until the power actually goes off. But when the power is on this alarm sure does let you know. This product is exactly what I was looking for! March 23, 2013
Rated 5.0 out of 5.0 by Just what I needed, great price and product I recently back fed my load center with a generator hookup and interlock switch (also bought at home depot) and I had no idea how I was going to tell when the power came back. I didn't know these things even existed until I was buying the interlock switch and saw this under the "customers also bought ...." section. This thing works great, install it in a knockout, ground it and wrap the antenna around one of the main feeds and your done. When it's enabled it beeps when power's present. I've seen others say it isn't loud enough, but mine is extremely loud. Ear piercing in fact. The price was better then amazon and the product itself seems well built. What more could you want. October 8, 2013
Rated 5.0 out of 5.0 by Excellent addition to use with interlock kit. Easy to install. Magnetic base allows you to attach to front panel. Wrap 8 inch antenna snug around left main power cable and hold in place with electrical tape for good connection/signal. Mine came with 9V battery. Very happy works very will. October 18, 2014
Rated 5.0 out of 5.0 by You need this if you have a manual transfer generator. I wondered how I would know when power was restored when I installed my generator interlock. This is a great solution for that problem. As others have said, wrap the sense-wire tightly around one leg of the incoming power and secure it with electrical tape. I used ty-wraps at both ends of the coil of wire on top of the tape to keep everything from unraveling. Mine is installed through a knock-out on the side of the box, and the alert signal is very loud! (I can hear mine installed in the basement from upstairs with no problem.) Overall, this is a great solution at a reasonable price. If you have a manual generator transfer, you need one of these. June 2, 2014
Rated 5.0 out of 5.0 by Works perfectly The utility power return alert is just what we needed. It was installed and it works perfectly. October 20, 2014
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