PV DC distribution board 1000V T2 Phoenix Contact Doktorvolt 4371 DV-4371-FOT

Surge protection for high-voltage photovoltaic installations

The Doktorvolt DC photovoltaic distribution board is a complete solution for protecting PV strings operating at voltages up to 1000V DC. Equipped with a VAL-SPP-T1-1000DC-PV-2+V-UT surge protection device of Type 1+2 class, the distribution board provides protection against atmospheric surges and switch-off surges generated during system operation.

The Type 1+2 (T1/T2) class surge arrester reacts to an impulse surge with parameters of 5 kA at a 10/350 µs wave and withstands a test current of 40 kA at an 8/20 µs wave. The voltage protection level of 4.2 kV effectively reduces impulse energy before it reaches the connected devices. The maximum continuous operating voltage Uc of 1200V DC provides a safety margin above the nominal system voltage.

Enclosure and operating conditions

The distribution board has a footprint of 142×210×100 mm (with cable glands and connectors: 142×240×100 mm) and occupies 4 modules on a DIN rail. The surface-mounted design allows for installation directly next to the inverter or on a building facade.

The enclosure, made of technopolymer, is characterized by resistance to UV radiation and corrosion - an important feature for multi-year exposure to atmospheric conditions. The polycarbonate door ensures dimensional stability and impact resistance. The EPDM rubber seal maintains flexibility across a wide temperature range, and the stainless steel screws do not require periodic tightening.

The IP65 protection rating means full dust-tightness and resistance to water jets from any direction - the distribution board performs well outdoors without an additional protective housing. The gray RAL 7035 color allows the device to be discreetly integrated into the building facade.

Wiring and solar connections

Internal wiring is made with BiT 1000 solar cables with a cross-section of 6 mm². The cables are supplied in black and red colors, which facilitates maintaining the DC installation polarity.

A set of 4 solar connectors (2× female + 2× male) is included with the distribution board. The IP67 protection rating allows for their year-round use in outdoor conditions. The impulse voltage of the connectors is 8 kV.

The manufacturer draws attention to the risk resulting from mixing connectors from different manufacturers - geometric mismatch leads to an increase in contact resistance, which generates heat that can lead to an installation fire. European standards IEC 62548 and IEC 60364-7-712:2017 prohibit the use of DC connectors from different suppliers in a single circuit.

Compliance and certificates

The distribution board meets the requirements of the EU directive 2002/95/EC RoHS and the CEI 23-48 standard, and its surge arrester is certified according to IEC 61643-31. The manufacturer has implemented a quality management system certified by TÜV SÜD according to the ISO9001:2015 standard - which guarantees the repeatability of production processes and consistency of parameters between units.

Optical signaling of the arrester status allows for assessing its wear without the need to disassemble the enclosure - after the varistor element has acted, the window changes color, signaling the need to replace the protection module.