Line protection MCCB with ETU320 — 63 A frame, 3-pole, shunt trip
The Siemens 3VA2063-6HL32-0KH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection duty, carrying a continuous current Iu of 63 A across its full 40 °C to 50 °C ambient range, with a slight thermal derating to 60.6 A at 55 °C and 53.6 A at 70 °C. The ETU320 electronic trip unit handles the overcurrent release; a built-in shunt trip (STL) release (order code 3VA9688-0BL33 for the integrated auxiliary trip) provides remote trip capability without an undervoltage release on this variant.
Breaking capacity — what the voltage-dependent ratings mean for panel coordination
This breaker delivers 242 kA at 240 V, 187 kA at both 415 V and 440 V, 121 kA at 500 V, and 4 kA at 690 V. The 242 kA figure at 240 V is the headline — it means this MCCB can safely interrupt a fault current up to that level on a 240 V line without upstream fuses or a current-limiting reactor. At 415/440 V the 187 kA rating still exceeds what most distribution transformers behind a typical 2000 kVA unit can deliver, so selectivity with downstream breakers is achievable without oversizing the main. The drop to 4 kA at 690 V is the practical limit for 690 V applications; if your system fault current exceeds that, this breaker is not the right choice for that voltage tier.
Physical fit and panel integration
Dimensions are 181 mm height, 105 mm width, 86 mm depth — a standard SENTRON 3VA2 frame footprint. The 105 mm width across three poles matches the typical 35 mm per-pole spacing on DIN-rail or backplate layouts. The auxiliary contact configuration ships as 2 auxiliary switches plus 1 trip alarm switch (HQ designation), which occupies the auxiliary terminal block and must be accounted for in the wiring duct clearance. Maximum power loss is 5.4 W, so no forced cooling is required in a standard IP30 enclosure but adjacent devices should not be thermally blanketed.