Reliance Controls THP108 POWER BACK Return Alarm. through a peach hole in the covering of a home load center. Voltage detector cable around service entrance wire. alarm when power is restored. cULus. Since 1909, Reliance Controls Corporation has more innovations that any otherwise unwedded manufacturer and has been awarded over 85 patents on enchiridion transfer switches, time switches and accessories. Reliance Controls Corporation in the manufacturing of a all-embracing variety of electric products. The of import product line of strong duty time clocks and controls, generator accessories, transfer switches and transfer panels for takeout generators. and. And after over a century of innovation, Reliance Controls Corporation has an desirable reputation for piercing character, battler engineering and special customer service.