Single switch FR311 20 250V 412900

Two-pole two-way switch for DIN rail

The FR311 switch enables power switching between two circuits - hence its primary function as a two-way switch. The device allows controlling one circuit from two points, which is a standard solution in lighting installations for staircases, corridors, and rooms where operational convenience requires independent switching from different locations.

The housing occupies one module on a DIN rail with a width of 17.7 mm. The compact format allows for efficient space management in distribution boards - particularly important in extensive installations with many circuits. Mounting on the DIN rail is fast and does not require additional brackets or surface-mounted enclosures.

Electrical parameters and load capacity

A rated current of 32 A at a voltage of 250 V AC classifies this switch as a component suitable for handling resistive and partially inductive loads. The manufacturer also specifies a switching capacity for fluorescent lamps up to 20 AX, meaning the device can handle the inrush currents of CFL and fluorescent lamps - a common case in commercial and office installations.

A short-circuit strength of 0.384 kA defines the maximum short-circuit current that the breaking contact can withstand for the time required for the upstream protection to operate. For a typical residential or office distribution board, this value is sufficient - provided that the overcurrent protection in the circuit is correctly selected.

The screw terminals accept conductors with a cross-section of 1.5-6 mm², covering both typical flexible cables (2.5 mm²) and thicker wires used for longer routes or larger loads.

Construction and operating conditions

The device has a mounting depth of 44 mm and height and depth dimensions of 94 × 76 mm respectively. The IP20 protection rating means there is no special resistance to water or dust - typical for equipment mounted inside electrical distribution boards where conditions are controlled.

The switch operates in temperatures from −5 to +40 °C, and during transport and storage, it withstands a range of −10 to +70 °C. The connection terminal markings are permanently applied to the device - facilitating correct connection without the need to consult documentation every time. A space for a label/marking allows the circuit to be described directly on the device.

Standards and certificates

The product meets the requirements of the IEC/EN 60669-1 standard, which defines the construction and parameters of switches used in building installations. Certificates confirming European compliance include, among others, the technical report OC/CB-FR_712329 and the VDE-40021636 certificate issued by the German standardization institution - these documents are available online as attachments to the Legrand product sheet (PDF format). CAD models for design are available as DWG files (3D models).