Why Choose the Finder 7P.21.8.440.0020 Type 2 Surge Protection Device?
The Finder 7P.21.8.440.0020 is a compact, single-pole Type 2 surge protection device (SPD) designed to protect low-voltage electrical installations against transient overvoltages caused by lightning-induced disturbances and electrical switching operations. Part of the Finder 7P Series, this DIN rail-mounted surge arrester uses metal oxide varistor technology to help safeguard electrical distribution equipment, industrial control systems and sensitive electronic components.
Designed for 400 V AC nominal electrical systems, the Finder 7P.21.8.440.0020 features a 440 V AC maximum continuous operating voltage (Uc), a 20 kA nominal discharge current (In) and a 40 kA maximum discharge current (Imax). Its 1.9 kV voltage protection level helps limit transient voltage stress on downstream equipment.
Featuring a replaceable varistor cartridge, visual protection status indication, IP20 protection and a compact 17.8 mm modular width, this Type 2 SPD provides an efficient solution for electrical distribution boards and industrial control panels. The device mounts onto a standard 35 mm DIN rail and can be incorporated into suitable single-phase or three-phase surge protection arrangements.
Key Advantages
- Type 2 surge protection against induced lightning overvoltages and electrical switching transients.
- Single-pole varistor configuration for compatible electrical distribution systems.
- 400 V AC nominal voltage for suitable industrial electrical applications.
- 440 V AC maximum continuous operating voltage provides appropriate voltage tolerance.
- 20 kA nominal discharge current for effective transient surge protection.
- 40 kA maximum discharge current for high-energy surge events.
- 1.9 kV voltage protection level helps limit overvoltage stress on connected equipment.
- Replaceable varistor cartridge enables convenient maintenance without replacing the complete SPD base.
- Visual protection status indication simplifies inspection.
- Compact 17.8 mm width conserves space inside electrical distribution boards.
- 35 mm DIN rail mounting supports straightforward installation.
- IP20 protection suitable for installation inside appropriately protected electrical enclosures.
- Optional remote status monitoring using a compatible Finder signalling connector.
- Suitable for industrial, commercial and infrastructure electrical protection systems.
Key Features
- Finder 7P Series surge protection device.
- 7P.21 single-pole surge arrester family.
- Type 2 SPD classification.
- Metal oxide varistor (MOV) protection technology.
- 400 V AC nominal voltage.
- 440 V AC maximum continuous operating voltage (Uc).
- 20 kA nominal discharge current (In), 8/20 µs.
- 40 kA maximum discharge current (Imax), 8/20 µs.
- 1.9 kV voltage protection level.
- 25 kA short-circuit current rating (Isccr).
- 125 A maximum upstream backup fuse rating for the specified parallel connection arrangement.
- Replaceable varistor module: Finder 7P.20.8.440.0020.
- Visual status indicator for operational and replacement condition.
- Optional remote signalling with compatible Finder 07P.01 connector.
- IP20 ingress protection.
- −40 to +80 °C operating temperature range.
- 35 mm DIN rail mounting according to EN 60715.
- 17.8 mm modular width.
- Screw terminal connections.
Technical Specifications
- Manufacturer: Finder
- Series: 7P Series
- Product family: 7P.21
- Model: 7P.21.8.440.0020
- Product type: Single-pole surge protection device
- SPD classification: Type 2
- Number of poles: 1
- Protection technology: Metal oxide varistor (MOV)
- Nominal voltage (Un): 400 V AC
- Maximum continuous operating voltage (Uc): 440 V AC
- Nominal discharge current (In), 8/20 µs: 20 kA
- Maximum discharge current (Imax), 8/20 µs: 40 kA
- Voltage protection level (Up): 1.9 kV
- Short-circuit current rating (Isccr): 25 kA
- Maximum backup fuse, parallel connection: 125 A
- Protection module: Replaceable varistor cartridge
- Replacement cartridge: 7P.20.8.440.0020
- Local status indication: Optical protection status indicator
- Remote signalling: Optional via compatible Finder 07P.01 connector
- Integrated remote signalling contact: No
- Operating temperature: −40 to +80 °C
- Ingress protection: IP20
- Mounting: 35 mm DIN rail
- Mounting standard: EN 60715
- Terminal type: Screw terminals
- Solid conductor cross-section: 1–35 mm²
- Flexible conductor cross-section: 1–25 mm²
- Recommended conductor stripping length: 12 mm
- Terminal tightening torque: 3 Nm
- Width: 17.8 mm
- Height: 82.8 mm
- Depth: 65.9 mm
- Approximate weight: 123.1 g
- Housing colour: Grey
- Relevant standard: EN/IEC 61643-11
- EAN: 8012823357553
- Manufacturer part number: 7P.21.8.440.0020
Type 2 Varistor Protection for Electrical Distribution Systems
The Finder 7P.21.8.440.0020 uses metal oxide varistor technology to provide rapid protection against transient overvoltages. During normal operation, the varistor presents high electrical resistance. When a sufficiently high transient voltage occurs, its resistance decreases rapidly, allowing surge current to be diverted through the SPD and its protective earthing arrangement.
With a 20 kA nominal discharge current and 40 kA maximum discharge current, the device is suitable for Type 2 surge protection applications where electrical equipment may be exposed to induced lightning surges and switching disturbances. Its 1.9 kV voltage protection level helps reduce the magnitude of transient overvoltages reaching downstream equipment.
The device is particularly suited to installation at the boundary between lightning protection zones LPZ 1 and LPZ 2, or other locations determined by the electrical installation's surge protection design. Multiple single-pole devices may be combined in appropriately engineered arrangements for three-phase distribution systems.
Replaceable Varistor Cartridge and Visual Status Monitoring
The Finder 7P.21.8.440.0020 incorporates a removable varistor protection module. If the cartridge reaches the end of its service life, it can be replaced with the compatible Finder 7P.20.8.440.0020 replacement module without removing the complete SPD base from the DIN rail.
A built-in visual status indicator allows maintenance personnel to inspect the condition of the protective element. For applications requiring remote monitoring, a compatible Finder 07P.01 signalling connector can be used to provide an external indication of varistor status.
The compact 17.8 mm width makes the device suitable for distribution boards where DIN rail space is limited. Correct installation requires appropriate backup overcurrent protection, suitable conductor routing and compliance with the manufacturer's wiring instructions.
Typical Applications
- Industrial electrical distribution boards.
- Three-phase 400 V AC power distribution systems.
- Commercial building switchboards.
- Industrial automation and PLC control panels.
- Manufacturing machinery electrical supplies.
- Motor control centres and variable frequency drive installations.
- Electric vehicle charging infrastructure.
- Road and tunnel lighting electrical systems.
- Lift and elevator electrical installations.
- Building management and HVAC control systems.
- Electrical infrastructure requiring secondary-stage surge protection.
- OEM electrical switchgear and control panel assemblies.
