Siemens 3NP427 Fuse Switch Disconnect

Siemens 3NP427 Fuse Switch Disconnect is a three‑pole fuse‑switch disconnector in the SENTRON 3NP1 family, designed to provide isolation and fuse protection for distribution circuits in a compact NH1 60 mm busbar system with screw terminals. In Siemens’ Industry Mall catalog the 3NP4276‑1CG01 variant is listed as a 3‑pole, NH1, 250 A device for a Busbar system 8US 60 mm with screw terminals, confirming its intended configuration and current handling for typical panel installations. The 3NP1 family is rated for up to 690 V AC (Ue) with insulation voltage up to 1000 V (Ui) and DC ratings around 440 V, making the fuse switch suitable for residential/industrial distribution gear and motor control panels where both switching and short‑circuit protection are required. Fusing is achieved with replaceable fuse links compatible with Siemens SITOR fuses (per DIN 43620), enabling coordinated protection within the same assembly. While Siemens’ own listings emphasize a 250 A variant for this model, third‑party and older catalogs sometimes cite a 240 A rating for 3NP427 devices, reflecting a range within the same 3NP family and busbar configurations; buyers should verify the exact variant and current rating for their enclosure and system requirements. This device is typically used to safely disconnect power for service or maintenance while providing inherent overcurrent protection, making it a common choice in low‑voltage distribution panels and equipment where compact, pre‑fused isolation is essential.