What the 90 A rating means for your load
The 3RF3090-1AA04 is a 1-pole semiconductor relay from the SIRIUS 3RF30 family, rated 90 A continuous at 48-460 VAC with a 24 VDC control voltage. That 90 A figure is the nominal continuous current through the output semiconductor — it's the rating you size the load cable and upstream protection for, not a surge or inrush figure. For resistive heater loads or lamp banks, this relay switches the full 90 A within the voltage window. For motor or transformer loads with high inrush, you'd typically derate per the manufacturer's guidelines; the 90 A continuous rating gives you the headroom for steady-state current after the start transient settles.
Panel integration and form factor
The 45 mm width (3SU form factor) mounts on standard DIN rail. The screw terminals accept the load and control wiring directly — no separate base or socket required. Packaging dimensions are 62 x 47 x 74 mm, single piece per unit. The 24 VDC control side is optically isolated from the power side, which simplifies panel wiring: you can run the DC control loop from a separate power supply without worrying about common-mode voltage on the AC line.