Why Choose the Finder 7P.24.8.275.0020 Type 2 Three-Phase Surge Protection Device?
The Finder 7P.24.8.275.0020 is a Type 2 three-phase 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 surge arrester features a 3+1 protection configuration comprising three metal oxide varistors and one gas discharge spark gap, making it suitable for compatible TN-S and TT electrical distribution systems.
Designed for 230/400 V AC three-phase installations, the Finder 7P.24.8.275.0020 features a 275 V AC maximum continuous operating voltage (Uc), a 20 kA nominal discharge current (In) and a 40 kA maximum discharge current (Imax). Its protection arrangement helps limit transient overvoltages reaching connected electrical equipment, including power supplies, automation controllers, electronic switching equipment and industrial machinery.
The device incorporates replaceable varistor and spark-gap modules, visual protection status indication and a compact four-module housing. With 35 mm DIN rail mounting, IP20 protection and a wide operating temperature range, it provides a practical surge protection solution for industrial switchboards, commercial distribution boards and building electrical infrastructure. This specific .0020 version does not include a remote signalling contact.
Key Advantages
- Type 2 surge protection against induced lightning surges and switching-related transient overvoltages.
- 3+1 protection configuration incorporating three varistors and one gas discharge spark gap.
- Compatible with TN-S and TT systems with neutral conductors.
- 275 V AC maximum continuous operating voltage for suitable 230/400 V AC installations.
- 20 kA nominal discharge current for an 8/20 µs surge waveform.
- 40 kA maximum discharge current for an 8/20 µs surge waveform.
- 1.2 kV L–N voltage protection level helps reduce transient voltage stress on connected equipment.
- 1.5 kV N–PE voltage protection level supports effective neutral-to-earth surge protection.
- Replaceable protection modules simplify maintenance and servicing.
- Visual varistor status indication enables straightforward inspection of protection condition.
- 50 kA short-circuit current rating supports suitable electrical distribution applications.
- Compact four-module construction conserves electrical panel space.
- 35 mm DIN rail mounting provides convenient installation.
- −40 to +80 °C operating temperature range supports demanding environments.
Key Features
- Finder 7P Series surge protection device.
- 7P.24 three-phase surge arrester family.
- Type 2 SPD classification.
- 3+NPE configuration for three-phase systems with neutral.
- Three metal oxide varistors for L1–N, L2–N and L3–N protection.
- One gas discharge spark gap for N–PE protection.
- 230/400 V AC nominal installation system.
- 275 V AC maximum continuous operating voltage.
- 20 kA nominal discharge current (In).
- 40 kA maximum discharge current (Imax).
- 1.2 kV L–N voltage protection level.
- 1.5 kV N–PE voltage protection level.
- 50 kA short-circuit current rating (Isccr).
- Replaceable varistor and spark-gap modules.
- Optical varistor condition indicator.
- No integrated remote signalling contact on the .0020 variant.
- IP20 ingress protection.
- 35 mm DIN rail mounting according to EN 60715.
- Approximately 71.8 mm housing width.
- EN/IEC 61643-11 surge protection device standard.
Technical Specifications
- Manufacturer: Finder
- Series: 7P Series
- Product family: 7P.24
- Model: 7P.24.8.275.0020
- Product type: Three-phase surge protection device
- SPD classification: Type 2
- Protection configuration: 3+1 / 3+NPE
- Number of protected conductors: 3 phases plus neutral
- Compatible earthing arrangements: TN-S and TT
- Protection technology: Three metal oxide varistors and one gas discharge spark gap
- Phase protection paths: L1–N, L2–N and L3–N
- Neutral protection path: N–PE
- Nominal phase-to-neutral voltage: 230 V AC
- Nominal three-phase system voltage: 230/400 V AC
- Maximum continuous operating voltage (Uc), AC: 275 V AC
- Maximum continuous operating voltage (Uc), DC: 350 V DC
- Nominal discharge current (In), 8/20 µs: 20 kA
- Maximum discharge current (Imax), 8/20 µs: 40 kA
- Voltage protection level, L–N: 1.2 kV
- Voltage protection level, N–PE: 1.5 kV
- Short-circuit current rating (Isccr): 50 kA
- Maximum upstream backup fuse: 160 A for the specified parallel connection arrangement
- Protection modules: Replaceable varistor and spark-gap cartridges
- Local status indication: Optical varistor condition indicator
- Remote signalling contact: Not included
- Operating temperature: −40 to +80 °C
- Ingress protection: IP20
- Mounting: 35 mm DIN rail
- Mounting standard: EN 60715
- Housing width: Approximately 71.8 mm
- Modular width: 4 DIN modules
- Maximum rigid conductor cross-section: 35 mm²
- Maximum flexible conductor cross-section: 25 mm²
- Relevant standard: EN/IEC 61643-11
- EAN: 8012823398143
- Manufacturer part number: 7P.24.8.275.0020
Type 2 Surge Protection for TN-S and TT Three-Phase Systems
The Finder 7P.24.8.275.0020 provides Type 2 transient overvoltage protection using a 3+1 circuit arrangement. Three metal oxide varistors are connected between the phase conductors and neutral, while a gas discharge spark gap provides protection between neutral and protective earth. This configuration is designed for compatible TN-S and TT electrical installations.
During a transient overvoltage event, the varistors become conductive and divert surge energy through the protective circuit. The gas discharge element provides the neutral-to-earth protection path, helping manage surge currents while supporting the intended earthing arrangement.
With a 20 kA nominal discharge current and 40 kA maximum discharge current, the device is suitable for electrical installations requiring protection against induced lightning surges and switching disturbances. Its 1.2 kV L–N and 1.5 kV N–PE voltage protection levels help reduce the voltage stress experienced by downstream equipment.
Replaceable Protection Modules and Practical DIN Rail Installation
The Finder 7P.24.8.275.0020 incorporates replaceable surge protection modules, allowing individual varistor or spark-gap elements to be renewed when required. This modular design can simplify maintenance and reduce the need to replace the complete surge arrester assembly.
A visual varistor condition indicator provides local information about the protective element's operational status. The 7P.24.8.275.0020 is the version without a remote signalling contact, making it suitable for installations where local inspection is sufficient. Applications requiring remote SPD status monitoring should use an appropriately specified variant.
The device mounts onto a standard 35 mm DIN rail and occupies approximately four modular spaces. It is designed for installation at the boundary between lightning protection zones LPZ 1 and LPZ 2, or at other suitable locations determined by the electrical installation's protection strategy. Correct conductor routing, protective earthing and upstream overcurrent protection are essential for effective operation.
Typical Applications
- Three-phase TN-S electrical distribution boards.
- Three-phase TT electrical installations.
- Industrial low-voltage switchboards.
- Commercial building distribution panels.
- Manufacturing machinery electrical supplies.
- PLC and industrial automation control cabinets.
- Motor control centres and variable frequency drive installations.
- Building management and HVAC electrical systems.
- Commercial lighting and electrical infrastructure.
- Electrical distribution systems requiring secondary-stage surge protection.
- Industrial power supplies and electronic control equipment.
- OEM electrical distribution and switchgear assemblies.
