The Siemens 3RV1918-5A is a SIRIUS auxiliary switch block that mounts onto Size S00 circuit breakers. It provides one normally-open and one normally-closed instantaneous contact, terminated via solder pin connectors — a fixed connection method that means you're wiring it directly into the PCB or terminal block, not clipping into a spring-cage or screw terminal.
Contact Ratings — What the Numbers Mean for Your Circuit
The maximum switching capability is 10 A, but that's only at 690 V AC-15 (solenoid/contactor coil duty). At the more common 24 V DC control voltage it's rated 2 A; at 110 V AC it drops to 0.5 A, and at 230 V AC it handles 4 A. The 690 V / 10 A rating is for the highest-voltage industrial control circuits — most panels run 400 V or less, so the practical limit is the lower current at your line voltage.
Panel Integration — Solder Pin Fit
This block snaps onto the front of a Size S00 Siemens circuit breaker. The solder pin connection means it is intended for a fixed wiring harness or PCB — not for field rewiring. Verify the pin spacing matches your terminal layout before adding to the BOM; the pins are not adjustable.