What this breaker is and what it does
The Siemens 3VA4120-6ED24-3AA0 is a 2-pole UL Frame 125 circuit breaker from the 3VA4 series, rated for line protection with a TM210 trip unit. It delivers 65 kA interrupting capacity at 480 V — that's the fault current it can safely clear without welding contacts or rupturing the case, sized for high-fault commercial and industrial panelboards where available short-circuit current is substantial. Overload protection is fixed at Ir=20 A (permanently set, not adjustable), and short-circuit pickup is Ii=15 x In, so magnetic trips at 300 A. The FTFM designation indicates it's a fixed thermal, fixed magnetic breaker — no field-adjustable dials, which means the BOM spec is locked and can't be drifted during installation.
Compliance and documentation
RoHS compliant since 13-05-19, and REACH Article 33 applies — lead (CAS 7439-92-1) is present above 0.1% w/w, so the downstream declaration chain is triggered if this goes into EU-market equipment. Export control is straightforward: AL N / ECCN EAR99, no special licensing for most destinations.
Panel integration notes
Packaged dimensions are 472 x 396 x 213 mm — that's the shipping carton, not the breaker footprint. The 3VA4 UL Frame 125 mounts in standard panelboard or switchboard cubicle, with line and load lugs sized for the 20 A continuous rating. Two-pole configuration fits a single module width in most UL panelboard layouts. The fixed Ir=20 A means no derating knob to mis-set; the breaker either fits the load or it doesn't.