The Acti9 iMSU‑255 is a compact, permanent surge protection relay that clamps voltage at 230 V AC to safeguard connected equipment. Its EN50550 compliance ensures reliable performance in industrial and commercial settings, while the integrated shunt release provides fast response to transient spikes. The module’s robust construction supports continuous operation, making it ideal for protecting motors, drives, and control panels from damaging over‑voltages.