What it is and what it does
The Siemens SENTRON 3VA1125-6EE42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated 25 A at 40 °C, designed for line protection in distribution panels. It carries a TM220 thermal-magnetic release — the thermal element handles overloads, the magnetic element clears short circuits — and delivers a breaking capacity of 220 kA at 240 V AC, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. The rated insulation voltage is 800 V, and the front face is IP40 rated for basic touch protection inside an enclosure.
What the ratings mean for your panel
The 220 kA interrupting rating at 240 V is the headline number for high-fault service-entrance or feeder applications. At 415 V the breaker still clears 154 kA, which covers most industrial distribution transformers. The 25 A continuous rating holds flat from 40 °C to 50 °C, then derates to 24 A at 55–60 °C and 23 A at 65–70 °C — useful to know if the breaker sits in a warm cabinet. The 4-pole design (3 phases + neutral switched) suits TN-S or TN-C-S systems where the neutral needs disconnection. Dimensions are 130 mm high, 101.6 mm wide, 70 mm deep — a standard SENTRON 3VA footprint that fits existing panel cutouts and busbar arrangements.
Thermal management and environment
Maximum power loss is 8.5 W — negligible for most enclosures but worth factoring into a sealed cabinet heat budget. Operating temperature range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. No undervoltage release, no shunt trip, no communication function on this variant — it is a straight thermal-magnetic breaker for basic overcurrent protection.