63 A MCCB with shunt trip — what the ratings mean for fit
The Siemens 3VA1063-3ED36-0JA0 is a SENTRON molded case circuit breaker (MCCB) rated 63 A at 40 °C, holding that same 63 A all the way up to 50 °C before it starts a gentle thermal derating curve — 62 A at 55 °C, 61 A at 60 °C, 60 A at 65 °C, and 58 A at 70 °C. That means in a warm panel you still get nearly full rated current; no need to oversize for ambient headroom unless you're above 70 °C. The interrupting ratings tell the real story: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at both 500 V and 690 V. That 75.6 kA at 240 V is the headline number — it handles high available fault current on a 240 V secondary without needing a current-limiting fuse upstream. At 690 V the 7.5 kA is still adequate for most motor branch circuits, but verify against your transformer's through-fault capability. This MCCB uses a TM210 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element clears short circuits. It's line-protection design, meaning it's sized to protect cable and bus rather than a specific motor or transformer. The shunt trip release (STL) lets you remotely trip the breaker via a control signal, useful for emergency-stop circuits or interlocking with a fire-alarm panel.
Panel fit and integration
The 3VA1063-3ED36-0JA0 measures 130 mm high, 76.2 mm wide, and 70 mm deep — a 3-pole frame that fits standard MCCB panel cutouts. The 70 mm depth means it clears most shallow enclosures; check your backpanel clearance if you're retrofitting into a tight cabinet. Rated insulation voltage is 800 V, so it's comfortable on 480/277 V and 600 V systems with margin. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The shunt trip is wired separately — it's not an undervoltage release, so it requires a sustained control voltage to hold the breaker closed. No communication module, no ground-fault monitoring, no trip indicator on this variant — keep that in mind if you need remote status feedback or GF protection.