Compact Type 2+3 AC Surge Protection for 3P+N Systems
LY1-D20/3(S)+1 is a compact 3P+N pluggable Type 2+3 AC surge protective device for three-phase plus neutral systems. Its coordinated MOV and GDT structure provides L-N and N-PE protection with 10kA nominal discharge current and 20kA maximum discharge current for downstream and final-distribution applications.
Class II+III / Type 2+3 protection for downstream AC circuits
3P+N configuration with L-N and N-PE protection
Coordinated MOV and GDT surge-protection technology
Pluggable modules with visual indication and optional remote contact
Suitable Applications
LY1-D20/3(S)+1 is suitable for three-phase plus neutral systems requiring coordinated Type 2+3 surge protection close to downstream equipment and final distribution circuits.
Unterverteilerschränke
For downstream protection in commercial and industrial three-phase plus neutral distribution boards.
Industrial Control Panels
Suitable for machinery controls, automation cabinets, HVAC panels, and production equipment.
Commercial Facilities
Helps protect office buildings, retail systems, building controls, and sensitive commercial loads.
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-D20/3(S)+1 compact 3P+N pluggable Type 2+3 AC surge protective device selection.
What is LY1-D20/3(S)+1 used for?
LY1-D20/3(S)+1 is used for downstream and final-distribution surge protection in three-phase plus neutral AC systems. It helps limit transient overvoltage through coordinated L-N and N-PE protection paths.
What does 3P+N mean?
3P+N means the SPD is designed for three phase conductors plus neutral, with MOV protection on the L-N paths and a GDT protection path between N-PE.
Is LY1-D20/3(S)+1 a Type 2 or Type 3 SPD?
LY1-D20/3(S)+1 is classified as Class II+III / Type 2+3, making it suitable for coordinated downstream and final-distribution surge protection.
What protection technology does it use?
It combines high-energy MOV protection on the L-N paths with a GDT on the N-PE path, providing coordinated surge protection for three-phase plus neutral systems.
What discharge current ratings does it provide?
It provides 10kA nominal discharge current and 20kA maximum discharge current on both the L-N and N-PE protection paths.
What should be confirmed before ordering?
Confirm the nominal L-N voltage, required Uc and Up level, 3P+N wiring arrangement, 125A maximum backup-fuse coordination, conductor size, DIN-rail space, and optional remote-contact requirement.











