Siemens HFXD63B200 Molded Case Circuit Breaker

This Sentron series breaker installs into Siemens P1, P2, and P3 panelboards, along with switchboards and motor control centers. It is a unit mount style that connects via a bolt-on method.

The letter H indicates a High Interrupting rating model within the Sentron FD frame family. The letter X specifies that the breaker is assembled with a non-interchangeable trip unit, preventing field modifications to the trip settings.

The thermal overload protection is permanently fixed at 200 amps. The magnetic short-circuit protection is adjustable via a dial on the breaker face. This allows electricians to modify the instantaneous trip point to handle high inrush currents without causing nuisance trips.

Both models are 200-amp, high-interrupting FD frame breakers with identical dimensions. The difference lies in the trip unit. The HFD63B200 has an interchangeable trip unit, while the HFXD63B200 features a non-interchangeable trip unit. They can physically substitute for each other, but the non-interchangeable HFXD63B200 version is often specifically required by local codes or facility standards.

The instantaneous magnetic pickup must be precisely calibrated according to a site coordination study. Setting the threshold too high risks severe equipment damage during a short circuit due to delayed tripping. Setting it too low will cause constant nuisance tripping on startup. Adjustments must only be performed by qualified personnel.