Camtec ESB303 Inrush Current Limiter 230/400Vac 3-Phase

Managing inrush current across three-phase LED installations and machine building applications is significantly more complex than single-phase — each phase conductor needs independent limiting, and most budget solutions treat all three as one. The Camtec ESB303 handles each phase separately.

A 3rd-generation peak and RMS inrush current limiter for 3-phase AC networks with a neutral conductor, the ESB303 actively limits inrush for 350ms on power-on across all three phase conductors, then bypasses via integrated relays so full load current passes through unimpeded. Limiting is precise to ±6% every cycle — no NTC thermistor degradation over time.

The ESB303 can be configured two ways: as three independent single-phase 230Vac limiters running in parallel (3×230Vac), or as a single 3×400Vac inrush limiter. Each phase connection supports up to 6,000µF of capacitive load at 48A peak (33.9A RMS). In practical terms, a single 16A MCB per phase can safely carry far more LED drivers or switch-mode power supplies than would otherwise be possible — reducing breaker count, cabling cross-section, and installation cost.

The neutral conductor (N) must be connected for the device to operate — the ESB303 powers itself between the phase conductors and neutral. For 3-phase systems without a neutral conductor, use the ESB00163 or ESB00323. The ESB303 is designed for capacitive loads only and is not suitable for use with transformers, AC motors, heaters, or DC voltage applications.

Housed in a compact 5TE (97.8mm wide) IP20 UL94V-0 ABS DIN-Rail enclosure. Rated to IEC/EN62368-1, IEC/EN61010-1, IEC/EN61010-2-201, IEC/EN60950-1 with ANSI/UL508 and CAN/CSA C22.2 listings. Spring-type terminals up to 6mm² / 10AWG. Operating temperature −40°C to +60°C continuous.