What this MCCB is and where it fits
The Siemens 3VA1120-4EF36-0JH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels and industrial switchgear. It carries a 20 A continuous rating across the 40 °C to 55 °C ambient range, derating to 19 A at 60 °C through 70 °C — so in a warm enclosure you lose 1 A, not a full trip unit step. Three-pole construction with a rated insulation voltage of 800 V means it handles 480Y/277 V and 600 V delta systems comfortably. The 70 mm depth and 76.2 mm width match the standard 3VA fixed-panel footprint — it bolts into the same mounting pattern as the rest of the 3VA1 family without re-drilling the subplate.
Breaking capacity — the real coordination number
The interrupting rating is what decides whether this breaker coordinates with downstream devices. At 240 V it clears 121 kA; at 415 V that drops to 75.6 kA; at 440 V it's 52.5 kA; and at 500 V / 690 V it holds at 11.9 kA. For a 480 V panel fed by a 1500 kVA transformer, the available fault current typically runs 30–50 kA — this breaker covers that with headroom. At 600 V (common in Canadian and some US industrial plants) the 11.9 kA rating means it's suited for lower-fault locations or where a current-limiting upstream device clips the let-through.
Auxiliary configuration and release
This variant ships with a shunt trip release (STL) for remote tripping and an auxiliary switch block carrying 2 auxiliary switches plus 1 trip alarm switch (HQ). The shunt trip lets a PLC, safety relay, or E-stop circuit open the breaker without a manual visit — common in conveyor interlock and emergency-off schemes. No undervoltage release, no communication module, and no ground-fault monitoring are fitted on this order code; those are separate option variants if the spec requires them.