What this MCCB is and what it does
The Siemens SENTRON 3VA1220-6EF42-0KA0 is a 4-pole molded case circuit breaker (MCCB) rated for 200 A continuous current (Iu) and fitted with a TM240 thermal-magnetic overcurrent release. It is configured for line protection — meaning it is intended to protect cables and busbars against overload and short-circuit, not motor or generator circuits. The 200 A rating holds flat from 40 °C through 50 °C, then derates linearly to 176 A at 70 °C, which is the maximum operating ambient. The rated insulation voltage (Ui) is 800 V, so the breaker is suitable for 690 VAC line-to-line systems common in industrial distribution.
Breaking capacity — what the numbers mean for your fault level
This breaker carries a 220 kA interrupting rating at 240 VAC, 154 kA at 415 VAC, 36 kA at 440 VAC, and 17 kA at 690 VAC. The steep drop between 415 V and 440 V reflects the transition from the IEC 60898-1 test voltage to the higher 440 V level where arc extinction becomes harder. For a 400 V distribution board (the most common industrial voltage in Europe and Asia), the 154 kA figure gives substantial headroom above typical transformer-fed fault currents of 25–50 kA. At 690 V, the 17 kA rating still covers most low-voltage motor control centre (MCC) applications. The 220 kA at 240 V is relevant for North American 120/208 V or 277/480 V systems where the line-to-neutral fault can be extreme near a large step-down transformer.
Physical fit and panel integration
The breaker measures 140 mm wide, 158 mm high, and 70 mm deep. It is a fixed-mount (non-withdrawable) MCCB designed for screw-mounting onto a backplate or mounting plate inside a distribution panel. The front face carries an IP40 rating — protected against tools and small wires, but not against water ingress, so it belongs inside a locked enclosure, not in a washdown zone. The 4-pole design covers three-phase plus neutral, which is standard for TN-S or TN-C-S systems where the neutral must be switched and protected. No auxiliary contacts or shunt trip are included as-delivered, but the design accepts the 3VA9688-0BL33 auxiliary trip block if remote tripping is needed.