Compact Type 2+3 AC Surge Protection for Three-Phase Systems
LY1-D20M/4(S) is a compact four-pole pluggable Type 2+3 AC surge protective device designed for three-phase plus neutral distribution systems. Its high-energy MOV modules provide coordinated surge limitation across L1, L2, L3, and N, with 10kA nominal discharge current and 20kA maximum discharge current.
Class II+III / Type 2+3 downstream surge protection
Compact 4P design for L1, L2, L3, and neutral protection
10kA nominal and 20kA maximum discharge current
Individually replaceable cartridges with optional remote contact
Suitable Applications
LY1-D20M/4(S) is suitable for compact three-phase plus neutral systems requiring coordinated Type 2+3 surge protection in limited DIN-rail space.
Three-Phase Distribution Boards
For compact commercial and industrial three-phase plus neutral distribution panels.
Industrial Control Panels
Suitable for machinery controls, automation cabinets, HVAC panels, and factory equipment.
Commercial Facilities
Helps protect building electrical cabinets, retail facilities, offices, and commercial equipment.
Solar Inverter AC Panels
For three-phase solar inverter AC-side panels when the selected Uc rating matches the system voltage.
FAQ
Common questions about LY1-D20M/4(S) compact four-pole pluggable Type 2+3 AC surge protective device selection.
What is LY1-D20M/4(S) used for?
LY1-D20M/4(S) is used for downstream and final-distribution surge protection in three-phase plus neutral AC systems. It provides coordinated protection for L1, L2, L3, and neutral conductors.
What does the four-pole configuration protect?
The four-pole configuration protects the three phase conductors and the neutral conductor in a three-phase four-wire electrical system.
Is LY1-D20M/4(S) a Type 2 or Type 3 SPD?
LY1-D20M/4(S) is classified as Class II+III / Type 2+3, making it suitable for coordinated downstream and final-distribution surge protection.
Does this product use MOV or GDT protection?
The verified product specifications identify high-energy MOV protection. The previous description referring to the complete product as a neon-gas GDT SPD should be removed.
What discharge current ratings does it provide?
It provides 10kA nominal discharge current In and 20kA maximum discharge current Imax, based on an 8/20μs current waveform.
Can each protection cartridge be replaced separately?
Yes. The pluggable design allows individual protection cartridges to be inspected or replaced without removing the permanently wired base.











