The Siemens 3NJ6900-4HF11 is a moving-iron analogue panel ammeter for the SENTRON 3NJ6 series of in-line switch disconnectors with fuses. It provides true RMS current indication on a 200 A scale via a 200/1 A current transformer input — the largest standard current rating in the 3NJ6900 pluggable ammeter range at the time of its introduction.

200 A for Main Distribution Feeders

The 200 A rating serves main incoming feeders, large sub-distribution panels, and major equipment supplies in low-voltage switchgear. At this level, the feeder is often critical infrastructure — the ammeter provides the operator with immediate visual confirmation of load status without relying on a powered digital display or SCADA terminal. The moving-iron mechanism delivers true RMS accuracy even when the 200 A feeder carries the aggregated harmonic currents of an entire downstream distribution network.

Decision Parameters