The SITOP SEL1400 EX brings selective current-limiting protection into ATEX/IECEx Zone 2 environments, distributing a 24V DC 60A supply across eight independently monitored branches rated 2A to 10A each. Certified II 3G Ex ec IIC T4 Gc under the increased-safety (Ex ec) concept, it is engineered for process industry control panels where DC distribution must meet both hazardous-area compliance and high availability.

Current Limiting in Hazardous Areas

In a Zone 2 atmosphere, any disconnection that produces an arc becomes a potential ignition source. The SEL1400's limiting characteristic mitigates this by clamping output current to the preset threshold rather than physically breaking the circuit during moderate overloads. Only sustained faults that persist beyond the 5s delay window trigger an electronic shutdown. This reduces the number of disconnect events — and the associated energy release — over the module's service life, an inherently safer operating profile for classified locations.

Installation Requirements

The module must be mounted inside a distribution box rated IP54 or higher, compliant with IEC/EN 60079-0, and requiring a tool to open. The 45mm DIN-rail footprint, screw-type plug-in terminals, and front-facing adjustments remain identical to the standard SEL1400, allowing standardized panel layouts across safe and classified zones within the same facility. Operating temperature range is -25°C to +60°C, with natural convection cooling.

Process Automation Integration

Each channel provides a three-color LED, manual reset button, and remote reset input. The common signaling contact (30V DC/0.1A) and monitoring interface feed per-channel diagnostic data to a PLC or DCS — operators can see which branch is in current-limiting mode, which has tripped, and the reason for shutdown, all without opening the enclosure.