Description
Katko 40A Changeover Switch: Reliable Manual Transfer Switching
The Katko 40A Changeover Switch is a load break switch engineered to make, carry, and break currents under normal circuit conditions, including specified overloads . It allows operators to manually transfer loads between two separate power supplies, such as a mains supply and a generator, ensuring continuity of power in critical applications. The distinct “1-0-2” switching positions provide clear selection between source 1, off, and source 2, while a mechanical interlock prevents the dangerous condition of both sources being connected simultaneously . Built to stringent IEC 60947-3 standards, this switch guarantees high performance and safety in industrial environments .
Katko 40A Changeover Switch: Key Specifications
| Specification | Details |
|---|---|
| Product Type | Manual Rotary Changeover Switch / Load Break Switch |
| Model Series | KU / KU-N / LoadSafe |
| Current Rating | 40 Amps (AC-21/22A) |
| Voltage Rating | Up to 690V AC |
| Number of Poles | 3‑pole (TP) or 4‑pole (TPN) options |
| Positions | 3‑position: I‑0‑II |
| Switching Positions | Change-over (1-0-2) |
| Rated Insulation Voltage (Ui) | 800V |
| Terminal Capacity (Cu) | 1.5 – 16 mm² |
| Terminal Torque | 1.8 Nm |
| Mounting | DIN Rail (EN 50022) or Base/Screw Mounting |
| Protection Rating | IP20 (open style) / IP65 (enclosed version) |
| Mechanical Endurance | 50,000 operations |
| Standards Compliance | IEC 60947-3, VDE, UL508 (select models) |
| Handle Type | Ergonomic rotary handle; padlockable in OFF position |
Katko 40A Changeover Switch: Advanced Safety and Design
The Katko changeover switch is built with several key features that enhance safety and longevity :
Silver Contact Technology: The switch utilizes robust silver-alloy contacts, which are excellent conductors and naturally resistant to corrosion and arc erosion. This ensures low contact resistance, reduces heat generation, and guarantees a long operational life even under frequent use .
1-0-2 Switching Logic: The clearly defined rotary positions allow for safe selection between power sources. The central ‘0’ position provides a positive off state, ensuring complete isolation of the load during maintenance or source changeover .
Padlockable Handle: The ergonomic handle features a mechanism that can be padlocked, typically in the ‘OFF’ position, to secure the circuit during maintenance and prevent unauthorized operation, complying with essential safety lockout/tagout procedures .
Mechanical Interlock: A built-in interlock mechanism physically prevents the switch from connecting both power sources at the same time, which could cause a dangerous short circuit or backfeed .
Versatile Installation: The modular KU series design allows for easy mounting on standard DIN rails within control panels, saving valuable space. For outdoor or harsh environments, enclosed versions with an IP65-rated polycarbonate enclosure offer protection against dust and water jets .
Katko 40A Changeover Switch: Applications
This robust changeover switch is essential for a wide variety of industrial, commercial, and infrastructure applications :
Generator Changeover Systems: The most common application, allowing safe and reliable switching between the mains utility supply and a standby generator in commercial buildings, data centers, and homes.
Industrial Machinery: For switching power sources or operating modes on equipment like pumps, conveyors, and compressors, particularly where redundancy is required .
Main Power Distribution: Used as a main switch or changeover in distribution boards to select between different incoming feeders.
Motor Control: Can function as a motor disconnect switch, with power ratings suitable for controlling 3‑phase motors up to 22kW (AC-23A) .
Bypass Applications: In uninterruptible power supply (UPS) systems or HVAC systems, allowing equipment to be bypassed for maintenance without interrupting power.
Katko 40A Changeover Switch: Installation and Safety Notes
Installation must be performed by a qualified electrician in accordance with local regulations (such as BS 7671) and the manufacturer’s instructions :
The switch is typically supplied as an open device for panel mounting on DIN rail. If an IP65 enclosure is required for outdoor or harsh environments, ensure the specified model is an enclosed unit .
For open devices, appropriate clearances must be maintained within the control panel to prevent accidental contact with live parts.
Cables must be terminated securely with the correct torque (1.8 Nm) to ensure reliable connections. For aluminum cables, special bi-metal connectors are required .
Always ensure the switch is operated in a no-load or light-load condition unless it is specifically rated for on-load switching (which the 40A AC ratings confirm it is) .
The switch is padlockable only in the ‘0’ (OFF) position. Never attempt to bypass this safety feature .
