The YCQ4E / YCQ4R is a compact dual-power automatic transfer switch (ATS) of PC type, rated 2 poles, 63 A. It is designed for household or light commercial applications. It monitors two AC power sources (main and standby) and switches to the standby source automatically when the main source fails, then restores to the main when it returns. It also allows manual override mode. Rated to work with 50-60 Hz and typical operating voltages around 400 V AC, with insulation voltage ratings up to 690 V in certain models. Suitable for rail-mount installation. Standard: IEC 60947-6-1.