Switch disconnector 3VA1, 100 A, 3-pole — what it is and what it does
The Siemens SENTRON 3VA1110-1AA36-0BA0 is a 3-pole switch disconnector in MCCB design, rated 100 A continuously from 40 °C up to 70 °C without derating — the thermal curve is flat across that entire band, so no headroom calculation is needed for elevated panel ambient. Rated operating voltage is 690 V AC and 500 V DC, with an insulation voltage of 800 V. This is a pure disconnector — no overload or short-circuit protection — intended for manual isolation and safety lockout where the upstream breaker or fuse provides the overcurrent protection.
Undervoltage release and connection details
The part includes a factory-fitted undervoltage release (UVR) for 24 V DC, which trips the disconnector when control voltage drops below the dropout threshold — a standard requirement for emergency-stop circuits and interlocking schemes where loss of control power must open the main disconnect. Connection is via front terminals (clamp type) for the main circuit, with no auxiliary contacts or communication function on this variant. An optional motor drive can be added for remote switching, though the base unit is manually operated.
Dimensions, mounting, and environmental limits
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this disconnector fits the standard MCCB footprint for 160 A frame size — it occupies three pole widths on a DIN rail or panel-mount base. Front protection is IP40, suitable for enclosed panel mounting where no water ingress is expected; the operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. Maximum power loss at rated current is 38 W — factor this into panel thermal calculations if multiple disconnectors are ganged in a small enclosure.
Lifecycle and sourcing posture
Mechanical service life is rated at 15,000 operating cycles typical.