Rated current and thermal derating
The Siemens 3VA1125-5EF36-0AB0 is a SENTRON molded case circuit breaker (MCCB) rated 25 A continuous at 40 °C ambient, with no derating needed up to 50 °C — the same 25 A holds at 45 °C and 50 °C. Above that, it steps down to 24 A at 55 °C and 60 °C, then 23 A at 65 °C and 70 °C. That flat thermal curve means the breaker can sit in a warm enclosure without losing headroom until the ambient crosses 50 °C. The TM240 overcurrent release is a thermal-magnetic type, fixed at 25 A, so the trip curve is factory-set — no field-adjustable thermal dial. For a 3-pole line-protection MCCB, that's the standard fit for fixed-load feeders where you want the breaker's rating locked to the conductor ampacity.
Breaking capacity — what the numbers mean for selectivity
The interrupting ratings span the common distribution voltages: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. The 187 kA figure at 240 V is the headline — it clears a bolted fault at the main panel without cascading upstream, so it can serve as a service-entrance breaker in a 240 V delta or wye system. At 690 V the 17 kA rating is still adequate for most motor-control-center feeder duty, but verify the available fault current at the point of installation. Rated insulation voltage is 800 V, which covers 690 V systems with margin. The breaker's design voltage class is 690 V maximum, so it is not rated for 1000 V applications.
Physical fit and panel integration
The 3VA1125-5EF36-0AB0 measures 130 mm high, 76.2 mm wide (3 inches), and 70 mm deep. The 3-inch width is the standard 3-pole MCCB footprint for this frame size — it occupies three 25 mm DIN spaces if mounted on a DIN rail, or bolts directly into a panel via the rear mounting slots. Depth of 70 mm (2.76 in) leaves clearance behind a standard 200 mm deep enclosure door. The auxiliary switch configuration is listed as 2 auxiliary switches HP (high-performance), integrated into the breaker's accessory slot. No undervoltage release, no shunt trip, no ground-fault monitoring on this variant — those are separate order-code options. The basic switch assembly order code is 3VA11255EF360AA0, which is the internal switching mechanism; the -0AB0 suffix on the main MPN indicates the factory-fitted accessory package.
Lifecycle and sourcing posture
Power loss at rated current is 8.5 W maximum — relevant for thermal budgeting inside a sealed enclosure. Storage temperature range is -40 °C to 80 °C; operating ambient is -25 °C to 70 °C. The storage minimum is the handling limit, not the running condition.