Siemens SENTRON 3VA4170-4ED34-0AA0 — Molded-Case Circuit Breaker, 70 A, 65 kA
The Siemens SENTRON 3VA4170-4ED34-0AA0 is a 3-pole molded-case circuit breaker (MCCB) rated 70 A at 40 °C, with a maximum operating voltage of 690 V AC. It's a current-production part, so you're not hunting for NOS or surplus — this is a standard catalog line from Siemens. Breaking capacity is 65 kA at 240 V and 25 kA at 480 V. That 25 kA at 480 V is the number that matters for most 480 V industrial panels — it tells you the breaker can safely clear a fault up to that level without welding contacts or venting arc gas. At 600 Y/347 V it's rated 14 kA. The TM210 thermal-magnetic trip unit is fixed, not adjustable. That means the overload and short-circuit pickup are factory-set — no dials to tweak on the front. If you need adjustable long-time or short-time pickup, you'd step up to an electronic trip version in the same frame size.
Thermal derating and panel fit
Rated current drops from 70 A at 40 °C to 63 A at 70 °C. If this breaker sits in a hot panel — near a drive, transformer, or in a NEMA 12 enclosure with limited airflow — use the 63 A figure for your load calculation. The 70 A rating is only valid at 40 °C ambient. Dimensions: 76.2 mm wide, 129.4 mm tall, 75.1 mm deep. That's a standard 3-pole MCCB footprint — fits most Siemens SENTRON panelboards and DIN-rail adapters without surprises. The front face is IP40, so it's protected against tools and wires but not washdown. Power loss is 16 W maximum at rated load. In a densely packed panel, that heat adds up — account for it in your thermal budget, especially if you're ganging several breakers side by side.