16 A MCCB with 121 kA interrupting capacity — what that means on the line
The Siemens SENTRON 3VA1096-4ED32-0CA0 is a 3-pole molded case circuit breaker rated 16 A continuous current (Iu) with a TM210 thermal-magnetic overcurrent release. The headline number here is the 121 kA breaking capacity at 240 V — that is the fault current this breaker can safely interrupt without welding its contacts or rupturing the case. At 415 V it still clears 75.6 kA, and at 690 V it holds 11.9 kA, so it is sized for high-fault panels where upstream transformers or utility feeds can dump serious energy into a bolted fault. The TM210 release is a fixed thermal-magnetic trip — no interchangeable trip units, no electronic adjustments. Thermal element handles overloads on an inverse-time curve; the magnetic element catches short-circuits instantaneously. That keeps the bill of materials simple and the panel build predictable, but it also means you commit to the 16 A rating at ordering — no field re-rating. An undervoltage release (UVR) is fitted as standard on this variant — part of the auxiliary release design. That means if the control voltage drops below the dropout threshold, the breaker trips open. Useful for safety circuits where a loss of control power should also kill the load. No auxiliary contacts, no shunt trip, no ground-fault module on this build.
Thermal derating — the real current you get above 50 °C
The 16 A rating holds flat from 40 °C through 50 °C ambient. At 55 °C it derates to 15.36 A, at 60 °C to 15.04 A, at 65 °C to 14.72 A, and at 70 °C to 14.4 A. If this breaker lives in a crowded panel or next to a heat source, the 55 °C figure is the one to size against — a 16 A breaker at 55 °C is really a 15.36 A breaker.
Mounting and panel fit
The 3VA1096-4ED32-0CA0 measures 76.2 mm wide by 130 mm high by 70 mm deep. That 70 mm depth is the dimension that matters when you are laying out the gland plate or door clearance — it is shallower than many older MCCB frames, so it fits retrofit panels where depth is tight. IP40 on the front means it is protected against tools and wires larger than 1 mm, but not against dust ingress or water — keep it inside a closed enclosure.