Air disconnector RNM III SA 24/4 03-051

Air disconnect switch – reliable connection in medium voltage networks

Air disconnect switch RNM III SA 24/4 is a key element of power infrastructure, designed for safe and efficient connection and disconnection of circuits in medium voltage overhead lines. The construction of this device, based on solid materials and precise workmanship, guarantees long-lasting and trouble-free operation in demanding environmental conditions. It is an ideal solution for both professional installers and end-users looking for reliable equipment for the construction and maintenance of power networks.

Construction and application – solidity and functionality

The disconnect switch brackets are made of S235 steel, ensuring high mechanical strength and corrosion resistance thanks to hot-dip galvanizing. This is important because these elements are exposed to the effects of atmospheric factors. The device is dedicated to mounting brackets on street lamps on spun concrete poles using steel tape. The manufacturer recommends using it with brackets with a maximum reach of up to 1.5 meters – this is a compromise between stability and installation efficiency. This disconnect switch is used in distribution networks with voltages of 15 and 24 kV, allowing both closing and opening of electrical circuits, as well as grounding of disconnected circuit sections.

Key features and parameters

The RNM III SA 24/4 disconnect switch is characterized by a number of technical parameters that determine its performance and safety:

• Rated voltage: 24 kV – ensures compatibility with typical medium voltage networks.

• Rated frequency: 50 Hz / 3 phases – standard frequency in the Polish power grid.

• Rated continuous current: 400 A – allows safe handling of large loads.

• Rated switching current: 20 A (in a low-inductance circuit and ring network) – provides effective protection against short circuits.

• Rated short-time withstand current: 16 kA (for 1 second) – guarantees resistance to sudden current surges.

• Rated peak withstand current: 40 kA – additional protection against extreme overvoltages.

• Mechanical endurance: 2000 Z/W cycles – confirms the long service life of the device.

The construction of the disconnect switch includes three independent poles (current paths) mounted on a common steel beam, hot-dip galvanized. The main contacts are made of tinned copper flats, ensuring excellent electrical conductivity and corrosion resistance. Flexible arc extinguishing contacts and arc suppression units minimize the risk of electric arc formation during switching operations, increasing work safety. Additionally, the possibility of mounting an earthing module expands the functionality of the device.