Siemens SENTRON 5SL1340-7MB: 40 A, C-Curve, 3-Pole MCB
The Siemens SENTRON 5SL1340-7MB is a 3-pole miniature circuit breaker (MCB) with a C-curve trip characteristic, rated for 40 A at 230/440 V AC, 50/60 Hz. Its breaking capacity is 3 kA per IEC 60947-2, sized for residential and infrastructure branch-circuit protection where fault currents stay within that limit. The 3-pole design switches all three phases simultaneously, which is typical for three-phase final sub-circuits in panelboards and distribution boards. The 5SL1340-7MB occupies 3 modular width units (54 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm.
Ratings and Application Context
Rated 40 A at 230 V single-phase and 440 V multi-phase. Power loss 4 W per pole at rated current. The 72 V DC maximum rating means it can also be used in some DC control circuits, but the primary application is AC branch protection. Mechanical service life is 4,000 operating cycles typical.