YUANKY BY1-25 Series Surge Protective Device (SPD) is a Class I+II (Type 1+2) overvoltage protection unit designed for installation on main distribution boards, fully compliant with IEC 61643-11:2011 and EN 61643-11:2012 standards. Available in 1P, 2P, 3P and 4P configurations, it is optimized for TN-C network systems with L-PE protection modes, delivering reliable surge discharge for both lightning-induced and switching overvoltages in low-voltage AC power distribution systems.

Built with high-energy metal oxide varistor (MOV) elements and a monoblock housing, this SPD combines robust surge capability with compact dimensions. It delivers a nominal discharge current of 25kA at 8/20μs waveform and a maximum discharge current of 100kA, plus an impulse discharge current of 25kA at 10/350μs waveform, fulfilling combined primary and secondary surge protection requirements in a single device. With an ultra-fast response time below 25 nanoseconds, it clamps surge voltage instantly to prevent damage to downstream sensitive electronics. The series covers nominal AC voltages from 120V to 400V at 50/60Hz, with matched maximum continuous operating voltages and graded voltage protection levels. It also withstands temporary overvoltage conditions, supports a 50kA short-circuit current rating and is compatible with up to 315A gL/gG back-up fuses, ensuring safe and stable operation under various electrical fault conditions.

Installed at the incoming end of main distribution boards, the BY1-25 SPD acts as the first line of surge defense for entire electrical installations. It is widely deployed in residential buildings, commercial complexes, office towers and retail centers to protect main distribution systems and downstream branch circuits. In industrial facilities, it safeguards low-voltage distribution rooms, production line control systems and power equipment against lightning surges and switching overvoltages from heavy machinery. It is also standard protection for data centers, telecommunication base stations, traffic signal systems and security power networks, where uninterrupted operation of sensitive electronic equipment is essential. Its integrated Class I+II design eliminates the need for separate SPD stages, saving valuable cabinet space and simplifying installation.

With reliable surge performance, wide voltage compatibility and compact monoblock construction, YUANKY BY1-25 series SPD provides a cost-effective, space-saving overvoltage protection solution for main distribution systems, making it a preferred choice for electrical contractors, system integrators and power projects globally.