Siemens NSB Q340 Miniature Circuit Breaker 3P

Siemens NSB Q340 Miniature Circuit Breaker is a 3-pole, 40-amp, 240-volt plug-in MCB designed to provide selective protection for three-phase circuits in low‑voltage distribution systems. It employs a thermal‑magnetic trip mechanism, offering reliable overcurrent protection with a 10 kA short-circuit interrupt rating and UL 489 listing, making it suitable for use in Siemens load centers and other compatible panels. The Q340 is a member of Siemens’ QP/MP family and is intended for three‑phase protection of branch circuits in commercial and light industrial applications, including feeders and equipment loads up to 40 A per pole. This device is a common-trip design, ensuring all three poles trip together when an overcurrent is detected, improving safety on 3‑phase circuits. It is specified for 240 V operation and is compatible with standard plug‑in mounting schemes used in Siemens distribution equipment.