Siemens 5SL6440-6 SENTRON MCB — 40 A, 4-Pole, B-Curve, 6 kA
The Siemens 5SL6440-6 is a SENTRON miniature circuit breaker rated 40 A at 400 V AC with a B tripping characteristic and a 6 kA breaking capacity certified to both EN 60898 and IEC 60947-2. Four poles (4P) with no switched neutral — it opens all phase conductors on a fault, which is the standard arrangement for a 3-phase + N incomer where the neutral is solidly connected. The B-curve (3–5× In instantaneous trip) suits resistive and general lighting loads in residential and light commercial infrastructure panels where inrush is low. At 6 kA SCCR it coordinates with downstream distribution boards that have a lower fault level; upstream a larger MCCB or fuse must limit the prospective fault current to this value.
Snap-on mounting to DIN rail (EN 60715) in any orientation. Mechanical service life of 10 000 switching cycles typical; this is a protective device, not a daily-switched disconnect — the figure governs the handle mechanism, not the contacts under load.
The 5SL6440-6 at 6 kA is the standard residential/infrastructure variant; the 10 kA sibling is specified where the utility transformer or service entrance delivers higher prospective fault current. Footprint and DIN-rail mounting are identical, so a panel specified around the 5SL6606-7YA can accept the 5SL6440-6 without rewiring, provided the fault level at the installation point does not exceed 6 kA.
Environmental range and approvals
Overvoltage category III (distribution board level) per IEC 60664. Energy limiting class 3 — the breaker limits let-through energy on a fault, reducing stress on downstream conductors and equipment. Approvals include EN 60898 (household-type MCB) and IEC 60947-2 (industrial circuit-breaker standard), giving dual certification for both residential and light industrial panels. Touch protection per the product feature ensures live busbar contacts are shielded when the breaker is installed in a distribution board.