Finder 7P.37.8.275.1003 – 7P Series Surge Protection Devices

Why Choose the Finder 7P.37.8.275.1003 Type 3 Surge Protection Device with Remote Signalling?

The Finder 7P.37.8.275.1003 is a compact Type 3 single-phase surge protection device (SPD) designed to provide fine protection against transient overvoltages in low-voltage electrical installations. Part of the Finder 7P Series, this DIN rail-mounted surge arrester is suitable for 230 V AC TT and TN-S systems with neutral, helping protect sensitive electrical and electronic equipment from switching disturbances and residual lightning-induced surges.

Featuring a 275 V AC maximum continuous operating voltage (Uc), a 3 kA nominal discharge current (In) and voltage protection levels of 1 kV between line and neutral and 1.5 kV between line/protective earth or neutral/protective earth, the Finder 7P.37.8.275.1003 is designed for supplementary protection close to electrical loads. Its combination of varistor and gas discharge technology provides protection across the L–N and N–PE paths.

A key advantage is its integrated changeover contact for remote status signalling, allowing the condition of the varistor protection element to be monitored externally. The device also supports series connection for loads up to 16 A or suitable parallel installation, making it a versatile solution for control panels, automation systems and commercial electrical distribution equipment.

Key Advantages

• Type 3 surge protection provides fine protection against residual transient overvoltages.
• Designed for 230 V AC single-phase systems with a neutral conductor.
• Suitable for TT and TN-S earthing arrangements when installed according to Finder's instructions.
• 275 V AC maximum continuous operating voltage supports normal operation on compatible electrical supplies.
• 3 kA nominal discharge current for an 8/20 µs surge waveform.
• 1 kV L–N voltage protection level helps limit transient voltage stress on connected equipment.
• 1.5 kV L–PE/N–PE protection level provides additional protection across earth-related paths.
• Integrated SPDT changeover contact enables remote monitoring of varistor status.
• Series connection for loads up to 16 A supports optimised protection close to sensitive equipment.
• Parallel connection capability provides flexibility in electrical panel design.
• Combined varistor and gas discharge protection supports effective line-to-neutral and neutral-to-earth surge limitation.
• Compact DIN rail construction conserves space in electrical cabinets.
• IP20 ingress protection for installation within suitable electrical enclosures.
• Remote monitoring compatibility supports PLC, alarm and building management applications.

Key Features

• Finder 7P Series surge protection device.
• 7P.37 single-phase Type 3 SPD family.
• Type 3 surge protection classification.
• 1+NPE protection arrangement.
• 230 V AC nominal system voltage.
• 275 V AC maximum continuous operating voltage (Uc).
• 3 kA nominal discharge current (In), 8/20 µs.
• 1 kV voltage protection level (Up) between L–N.
• 1.5 kV voltage protection level (Up) between L–PE/N–PE.
• Varistor and gas discharge protection technology.
• Integrated remote signalling changeover contact.
• SPDT auxiliary contact configuration.
• 16 A nominal load current for series connection.
• Series and parallel installation options.
• 35 mm DIN rail mounting according to EN 60715.
• IP20 ingress protection.
• Operating temperature range: −40 to +80 °C.
• Compact housing for electrical distribution and control panels.

Type 3 Fine Surge Protection for Sensitive Electrical Equipment

The Finder 7P.37.8.275.1003 is intended for the final stage of a coordinated surge protection system. While Type 1 and Type 2 devices are typically used to manage higher-energy surge events at upstream distribution points, a Type 3 SPD provides supplementary voltage limitation closer to sensitive electrical loads.

Its 1+NPE protection arrangement combines varistor and gas discharge technologies to protect the line-to-neutral and neutral-to-earth paths. The device has a 3 kA nominal discharge current and helps limit transient voltages to 1 kV across L–N and 1.5 kV across L–PE/N–PE under the specified test conditions.

This makes the Finder 7P.37.8.275.1003 particularly useful for protecting electronic power supplies, PLCs, instrumentation, communication equipment and control electronics from residual surge voltages. It should be selected and coordinated with upstream protective devices according to the installation's surge protection requirements.

Integrated Remote Monitoring and Flexible Series or Parallel Installation

The Finder 7P.37.8.275.1003 incorporates an integrated SPDT changeover contact for remote signalling of varistor status. This enables the condition of the surge protection element to be monitored by compatible PLC inputs, alarm circuits, supervisory control systems or building management equipment.

The device can be installed in series with a protected load up to 16 A, providing a convenient arrangement for protecting individual electrical circuits. It also supports suitable parallel connection, allowing engineers to select an installation method that matches the electrical distribution design.

For parallel installation, Finder's wiring guidance specifies appropriate overcurrent protection, including a 16 A gL/gG backup fuse in the illustrated arrangement. The device mounts on a standard 35 mm DIN rail and is intended for installation within a suitable electrical enclosure. Correct earthing, short connection conductors and appropriate SPD coordination are essential for effective protection.

Typical Applications

• Single-phase 230 V AC electrical control circuits.
• Industrial PLC and automation control panels.
• Electronic power supply protection.
• Building management systems.
• Commercial electrical distribution boards.
• Instrumentation and monitoring equipment.
• Industrial communication and signalling systems.
• HVAC control electronics.
• Electrical cabinets requiring remote surge protection status monitoring.
• Machinery control and electronic interface circuits.
• Final-stage protection in coordinated Type 1, Type 2 and Type 3 SPD systems.
• TT and TN-S single-phase installations with neutral.