Carlo Gavazzi RM1A Zero Switching SSRs are industrial single-phase AC Solid State Relays (SSRs) with a built-in varistor. This built-in varistor secures transient protection for heavy industrial applications. These SSRs utilize Direct Copper Bonding (DCB) technology and feature self-lifting terminals, a clip-on IP20 protection cover, and an LED indicator. The RM1A SSRs can be used for resistive, inductive, and capacitive loads. These zero-switching relays switch ON when the sinusoidal curve crosses zero and OFF when the current crosses zero. The RM1A SSRs offer up to 1400VP blocking voltage, >4000VACrms opto-isolation, and two input ranges, including 3VDC to 32VDC and 20VAC to 280VAC/22VDC to 48VDC.