What the ratings mean for fit
The Siemens SENTRON 3VA2010-7KQ42-0AA0 is a 4-pole molded case circuit breaker rated for a continuous current of 100 A across the full ambient temperature range from 40 °C to 70 °C — no derating needed up to that ceiling, which simplifies panel design in warm enclosures. The interrupting capacity hits 330 kA at 240 V and still delivers 242 kA at 415 V and 440 V, so it handles high-fault locations like transformer secondaries or large motor control centers without cascading upstream. At 690 V the rating drops to 3 kA, which is typical for a 100 A frame — that voltage class is not where this breaker is meant to clear high faults; it's for distribution-level isolation at that point. The ETU860 electronic trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves, plus communication capability for remote monitoring and coordination. The ground-fault monitoring uses summation current formation on L + N, which catches leakage without a separate sensor. Insulation voltage is rated at 800 V, so it's comfortable in 690 V systems as a line-protection device. Mounting footprint is 181 mm high by 140 mm wide by 86 mm deep, with IP40 protection on the front — fine for a clean indoor panel, but keep it out of washdown zones. Power loss is 7.7 W maximum, which is modest for a 100 A frame and won't drive much heat into the enclosure.
Peer comparison — when the 8HL matters
The closest sibling is the 3VA2010-8HL42-0AA0. Both are 4-pole, 100 A, same frame size. The difference is the trip unit: the 7KQ42 carries the ETU860 with ground-fault monitoring and communication; the 8HL42 uses a simpler thermal-magnetic release. If your panel was specified around the 8HL42, the 7KQ42 will bolt into the same mounting pattern and bus connection — no rewiring needed — but you'll have an electronic trip with settings to configure, which changes the coordination study. For a drop-in replacement on a line-down emergency, the physical fit is identical; just verify the trip curve matches what the panel was originally coordinated for.