Surge protection device T1, T2 (B, C) - without leakage current ETITEC SM T12 300/12,5 3+1 002440550

Advanced surge protection for main switchboards

The ETITEC SM T12 surge protective device is a modern Type 1+2 solution that effectively protects electrical installations from the effects of atmospheric discharges and switching surges. The device is designed for installation in the main switchboard as comprehensive protection against surges originating from direct and indirect lightning strikes.

Construction and protection technology

The heart of the device is a combined varistor-spark gap technology, where elements are connected in series for maximum protection effectiveness. The varistor, made of zinc oxide ZnO, is characterized by a very fast response time of <25 ns and a low protection level of <1,5 kV. An additional spark gap in the N-PE pole provides an extra layer of security.

The 3+1 construction means three phase poles with varistors and one N-PE pole containing a spark gap - an ideal solution for TT and TN-S network systems. The absence of leakage current significantly increases operational efficiency and reduces energy losses in the system.

The modular design allows for quick replacement of the varistor insert without the need to dismantle the entire base. The housing, made of durable UL94 V-0 thermoplastic, ensures resistance to environmental conditions and self-extinguishing properties.

Operating parameters and performance

The device operates at a continuous operating voltage of 300 V AC with a rated voltage of 240 V. It withstands an impulse current of 12,5 kA (10/350 µs) per pole and a maximum discharge current of 65 kA (8/20 µs). The specific energy is 39 kJ/Ω, which guarantees a high surge energy absorption capacity.

The operating temperature range from -40°C to +85°C allows for installation in various environmental conditions. The maximum cross-section of connected conductors is 35 mm² for solid or stranded wire and 25 mm² for flexible cable.

Internal thermal protection automatically disconnects a damaged element from the power grid in case of overheating. A short-circuit strength of 25 kA ensures safety even in the event of system failures.

Installation and status signaling

Installation is carried out on a standard DIN TH-35 mm mounting rail, occupying 4 modules. The IP20 protection rating ensures safe indoor installation in switchboards. Optical status signaling via a colored indicator allows for quick monitoring of the device's functionality - the green color indicates correct operation.

The terminal tightening torque should not exceed 4,5 Nm. In installations where the main switch is greater than 315 A, it is recommended to use additional gG pre-protection max. 315 A.

The device complies with the requirements of PN-EN 61643-11 and IEC 61643-11 standards and is compatible with all standard TN-S and TT network systems.