The SITOP SEL1200 EX combines ATEX/IECEx Zone 2 certification with fast electronic switching protection across eight 24V DC channels. Certified II 3G Ex ec IIC T4 Gc, it delivers selective fault isolation — 30ms trip on heavy overloads — to keep hazardous-area control systems running even when one field device faults, without the arc risk of mechanical circuit breakers.

Electronic Switching in Classified Locations

Traditional mechanical circuit breakers produce arcs during disconnection, which limits their applicability in Zone 2. The SEL1200 EX uses semiconductor-based switching: when a channel detects overcurrent, an electronic switch opens the circuit without mechanical contacts. The inverse-time curve provides three trip bands — ~30ms for hard shorts (>2× setting), ~1s for moderate overloads (~1.5×), and ~5s for borderline conditions (>1.0×) — so brief inrush peaks ride through while genuine faults are cleared decisively.

Field Instrumentation Power Distribution

With eight channels at 2–10A each, a single module can power an array of Zone 2 field devices: 4–20mA loop-powered transmitters, solenoid pilot valves, gas detectors, and analyzer sample conditioning systems, each on its own protected channel. A fault on one transmitter loop does not take down the entire field junction box — the remaining seven channels stay live, and the tripped channel's red LED and common signaling contact alert the DCS immediately.

Compliant Installation

The module must be installed inside a distribution box rated IP54 or higher per IEC/EN 60079-0, with tool-required access. The 45mm DIN-rail housing, screw-type plug-in terminals, and front-facing controls match the standard SEL1200 family, simplifying panel design when a facility has both classified and unclassified zones. Operating temperature is -25°C to +60°C with natural convection.