What it is and where it fits
The Siemens 3VA9224-0RL30 is an RCD820 advanced residual current device from the SENTRON family, designed as a load-side mounted accessory for 3VA2 molded case circuit breakers. It's a 4-pole, type A RCD rated at 250 A operational current at AC, covering the full range from 100 to 690 V supply voltage. This is the module that bolts onto the line side of a 3VA2 breaker to add ground-fault protection without replacing the entire breaker — a clean retrofit for an existing panel.
What the ratings mean for the buyer
The adjustable residual current response spans from 0.03 A up to 30 A — ten selectable thresholds (0.03, 0.05, 0.1, 0.3, 0.5, 1, 3, 5, 10, 30 A). That range covers everything from sensitive personnel protection at 30 mA through to equipment protection at 30 A for large feeder circuits. The non-tripping time is equally flexible: adjustable from 0 ms up to 10,000 ms in eleven steps (0, 0.06, 0.15, 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0 s). This lets you delay tripping through inrush or transient leakage that would nuisance-trip a fixed RCD, while still clearing a sustained fault. The pre-alarm indication triggers at 30% and 60% of the set residual current — a heads-up before the trip threshold is reached, useful for predictive maintenance on a motor feeder or conveyor line. Type A design means it detects both sinusoidal AC residual currents and pulsating DC residual currents — the kind generated by single-phase rectifiers, VFD front ends, and switching power supplies common in modern control panels. That makes it a better fit for mixed-load panels than a basic AC-type RCD. The module supports remote-controlled tripping and communication with residual current equipment, so it can be integrated into a building management or SCADA system for remote indication and trip control. It also offers a selectable RCD or monitoring mode — you can use it purely as a monitor without tripping the breaker, which is handy for commissioning or tracking intermittent ground faults.
Mounting and integration
Mounts via screw fixing directly onto the load side of a 3VA2 molded case circuit breaker — no DIN rail required, no extra wiring between breaker and RCD. The infeed can come from the top or bottom, giving flexibility in tight enclosures. Main circuit connection is by busbar connection, keeping the assembly compact. The module measures 139.6 mm wide by 115 mm tall by 86 mm deep — plan for that depth behind the panel door, especially if the breaker is in a shallow enclosure. Front protection is IP40 — fine for a dry electrical panel, but not rated for washdown or outdoor exposure without a secondary enclosure. Operating temperature range is -40 °C to 80 °C, which covers most indoor industrial environments and cold storage applications.