What it is and what it does
The Siemens 3VA1112-1AA42-0JA0 is a SENTRON 3VA1 switch disconnector in a molded-case circuit breaker (MCCB) footprint — a 4-pole load-break switch rated for 125 A continuous, with no overcurrent or short-circuit protection built in. It is designed for isolation and switching duty where the upstream protection is handled separately. Rated 125 A flat across the full operating temperature range from 40 °C through 70 °C, so no derating is needed as the panel warms up — a clean spec for panel builders sizing busbars and cable lugs. The shunt trip release (STL) accepts 110–127 V DC or AC 50/60 Hz, letting a remote safety relay or E-stop circuit open the switch without a manual handle pull.
Ratings and what they mean for fit
Rated insulation voltage 800 V and operating voltage 690 V AC / 600 V DC — this covers 480/277 V and 600 V industrial systems with headroom, and handles 400 V DC bus applications common in battery or UPS circuits. Maximum power loss of 38 W at rated current — a useful figure for enclosure thermal calculations; at 125 A continuous that loss is manageable in a standard steel enclosure with moderate ventilation. Mechanical service life of 15 000 operating cycles — typical for a switch disconnector in this frame size; adequate for daily isolation in a production line but not for frequent motor switching. Front IP40 protection on the front face — protected against tools and small wires, but not washdown. Mount in a clean indoor panel, not a food-processing or outdoor location.
Panel integration
Dimensions: 130 mm height, 101.6 mm width, 70 mm depth — a 4-pole MCCB-form-factor switch that fits standard panel cutouts and busbar systems for the 3VA1 frame 160 family. Main circuit connection is via front busbar terminals with nut keeper kits included — no separate lug kit to order. The busbar connection type means it is designed for horizontal or vertical busbar stacking in a distribution panel. An optional motor drive can be added for remote switching (product extension optional).