Finder 7P.04.8.260.1025 Type 1+2 Three-Phase Surge Protection Device

Type 1+2 surge protection for three-phase TT and TN-S incomers

The Finder 7P.04.8.260.1025 is a Type 1+2 surge protection device (SPD) for 230/400 V three-phase TT and TN-S systems with neutral. It combines a varistor with an encapsulated spark gap (GDT) on each of L1, L2 and L3 to neutral, plus a spark gap protection between N and PE. The result is a device that can take a direct lightning current, with no following current, and still gives a low voltage protection level of 1.5 kV.

It is designed for the origin of an installation, at the LPZ 0 to LPZ 1 boundary or higher, where a building has an external lightning protection system or an overhead supply. The four replaceable modules plug into a common base, each pole is 36 mm wide on a 35 mm DIN rail, and the housing can be mounted upside down thanks to dual terminal markings and a new restraint system for the modules.

Technical specifications

Where a Type 1+2 device is used and how to connect it

Surge protective devices are coordinated in stages: a Type 1 or Type 1+2 device at the building entrance (LPZ 0 to LPZ 1), a Type 2 device downstream at distribution boards (LPZ 1 to LPZ 2), and optionally Type 3 at the equipment. The 7P.04 is intended for the first stage, typically in the main distribution board next to the incomer, where lightning current can enter through the supply or a connected structure. The datasheet lists sister types: the 7P.03 for TN-C systems without neutral, the 7P.05 for TN-S with varistor + GDT between N and PE, and single-phase 7P.01/7P.02 devices.

Finder recommends the shortest possible connection to the local equipotential bar and describes a V-shape (series) connection that avoids the inductive voltage drop in the connecting wires; with this arrangement the downstream circuit is limited to 125 A, the maximum current through the double terminals. For higher currents the SPD is connected in parallel (T-shape) with a separate overcurrent device. The datasheet states minimum copper cross sections for the SPD connection of 16 mm2 where significant lightning current is expected for Type 1, otherwise 6 mm2.

Selection checklist

Confirm the earthing system (TT, TN-S or TN-C), the nominal voltage and the highest expected continuous voltage UC, then check the Iimp and Itotal values against the lightning protection design. Match the upstream fuse or breaker to the maximum overcurrent protection in the datasheet (250 A gL/gG, or 125 A in a V-shape connection). The remote contact, which signals healthy, replace or module presence, can be wired to a PLC or alarm panel. Coordination with downstream Type 2 devices needs a suitable distance or decoupling; use the manufacturer’s guidance. The SPD is not a substitute for an external lightning protection system.

Documents and quotation

The attached Finder 7P series datasheet gives the full SPD range (Type 1, 1+2, 2, 3 and signal-line devices), outline drawings, wiring and the explanatory chapters on SPD parameters. The same file lists the approvals by type, so please check the logos on the datasheet against the certificates your project needs. When requesting a quotation for the 7P.04.8.260.1025, tell us the system (TT or TN-S), the line current, the fuse rating and any remote signalling requirement. See also Automation Accessories.