Withdrawable Low-Voltage Switchgear

All three share the same rated operating voltage, horizontal busbar current, degree of protection and cubicle envelope; the differences sit in three places. Frame and mechanism: MNS is a C-profile assembly, GCS a standard modular design with a screw-driven mechanism, GCK an 8MF section-steel assembly with a lever-driven one. Fault level: MNS and GCS reach 80 kA short-time withstand for 1 s and 176 kA peak, GCK 50 kA and 105 kA. Circuit density: the GCS outgoing section takes up to 22 circuits. Projects with a high fault level or dense circuits take MNS or GCS; ordinary 380 V distribution and motor control is well served by GCK.

It comes down to the cost of an outage. A withdrawable unit is replaced whole, identical ratings interchange, and one faulty circuit does not require de-energising the busbar section. A fixed assembly is simpler and cheaper to build but maintenance means shutting the circuit down, sometimes the whole section. Sites with many circuits, continuous production and a standardised spares regime take the withdrawable pattern; sites with few circuits and planned outages are served by fixed. Both can be mixed in one line-up.

Three things give a preliminary scheme: the low-voltage distribution diagram, rated operating voltage and total line-up current, and the short-circuit capacity. For a contract-grade quotation, add the circuit schedule with the rating of each way, the starting method for motor circuits, reactive compensation rating, cable entry arrangement and cable sizes, control supply and communication interfaces, installation environment, and the standards and document list for the destination market.

It follows the unit size and the cubicle dimensions. Drawer units are tiered on a module pitch, so smaller units mean more tiers in the same cubicle, and the GCS outgoing section takes up to 22 circuits. The layout also has to leave room for the vertical busbar and cable compartments, and the vertical busbar current has to be checked against the load of each way. Send the circuit schedule and we will set out the arrangement cubicle by cubicle.

Units of the same rating interchange with one another, which is the point of the withdrawable design. A unit is withdrawn whole and replaced, keeping the work inside that unit while the other circuits on the same busbar section stay live. Interchangeability depends on matching unit size, control-plug type and terminal assignment, so the spare-unit list is settled together with the technical agreement.

Yes. The component platform is agreed at project confirmation stage against the technical agreement, and the final types, ratings, lead time and document scope follow the confirmed component list. The one thing to check alongside it is the mounting interface — changing breaker brand within the same cubicle type does not guarantee the same drawer module pitch or control-plug arrangement.

Yes. Switchgear is supplied as equipment while a power module or MV switchgear E-House is supplied as an enclosure — the first is the panel itself, the second covers the enclosure, equipment layout, auxiliary systems and interface integration. Where the line-up goes inside a module as the low-voltage primary equipment, ETENZ details the line-up arrangement, busbar connections and in-module interfaces, and the delivery boundary is settled once at contract stage.

Standard documents travelling with the panels are the approved project drawings, component list, wiring records and packing list. Inspection records are issued to the scope agreed in the order technical agreement; where witnessed tests or a specific report format are needed, raise it during quotation and technical clarification so test and witness slots can be arranged.