Siemens 5SY6140-8 SENTRON MCB — D-curve 40 A, 1-pole
It is designed for 400 V AC circuits and carries a 6 kA breaking capacity per EN 60898, with a higher 10 kA rating under IEC 60947-2.
Breaking capacity and standards coverage
The 5SY6140-8 carries multiple breaking capacity ratings depending on the standard applied: 6 kA per EN 60898 for general household/commercial use, 10 kA per IEC 60947-2 for industrial panel applications, and 5 kA per UL 1077 / CSA C22.2 No.235 for North American supplementary protection. For DC circuits, it is rated at 15 kA per IEC 60947-2 up to 72 V DC. This range of ratings means the same part can be specified across different regulatory jurisdictions — EN, IEC, UL, CSA — without swapping SKUs.
Physical fit and environmental ratings
Application context — D-curve for inductive loads
The D tripping characteristic (10–20× In magnetic trip) makes this 40 A breaker a natural fit for motor branch circuits, small transformers, welding equipment, and other loads with high magnetizing inrush. It is explicitly suited for mechanical engineering and industrial environments per the manufacturer's designation. The 1-pole format handles single-phase circuits; for three-phase motor loads, three units would be ganged. Touch protection is integrated on the terminals.