The Siemens 5SY8315-7 is a SENTRON miniature circuit breaker (MCB) — a 3-pole unit with C-curve tripping characteristic, rated 400 V AC at 50/60 Hz. That puts it in the high-breaking-capacity class for industrial panelboards and distribution boards where fault levels are high. The C-curve (trips at 5–10× rated current) suits it for motor circuits, transformers, and lighting loads with moderate inrush — typical for mechanical engineering and industrial applications. Rated current is 1.6 A at 45 °C, derating to 1.53 A at 55 °C and 1.57 A at 50 °C, so ambient temperature in the enclosure matters for sizing.
The 70 kA rating at 400 V AC (IEC 60947-2) is the headline figure — it allows this MCB to be used as the main incoming device in sub-distribution boards with high fault current. For DC circuits, it's rated 15 kA per IEC 60947-2. Under UL 1077 and CSA C22.2 No. 235, the breaking capacity is 5 kA. Selectivity with upstream devices is achievable given the high interrupting rating; coordination tables from Siemens should be consulted for specific series combinations.
Physical integration
Installation depth 70 mm. Sealable — suitable for applications requiring tamper-proof covers. Halogen-free and silicon-free construction.