What it is and what it does
The Siemens 3RT1016-1BB42-ZW98 is a SIRIUS power contactor in frame size S00, designed for switching motor loads and resistive loads in control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, so it integrates into standard industrial enclosures without special brackets. The coil is rated 24 VDC with a pickup threshold of 0.85 and a dropout threshold of 1.1 times rated voltage, meaning it pulls in reliably at about 20.4 V and drops out at about 26.4 V. Closing and holding power are both 3.3 W DC, so the coil draw is constant — no power-saver circuit needed, but the holding dissipation is the same as the inrush, which matters for thermal budgeting in a densely packed panel. Main circuit terminals are screw-type, accepting 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid or stranded conductors. AWG equivalents are 2x (20 to 16), 2x (18 to 14), and 1x 12. That covers most panel wiring up to 4 mm² without needing bootlace ferrules, though ferruled stranded is fine within the same cross-section range.
Ratings and what they mean for your load
The contactor is rated for AC-2 duty at 400 V at 4 kW, and AC-4 at 400 V at 8.5 A. AC-2 covers slip-ring motor starting and reversing; AC-4 covers plugging and inching of squirrel-cage motors. For resistive loads (AC-12), the maximum operating current is 10 A. These are the duty-specific ratings that govern real switching life — the AC-4 figure is the one to check if your application involves frequent reversing or jogging. Motor power ratings at higher line voltages: 4.5 kW at 500 V and 5.5 kW at 690 V. That makes it suitable for 400 V class motors up to about 4 kW, and for 690 V delta-connected motors up to 5.5 kW, common in mining or heavy industrial installations. Short-circuit protection coordination: with type 2 coordination (no welding of contacts on fault), use a gL/gG fuse rated 20 A. With type 1 coordination (contacts may weld but no fire or shock hazard), use a 35 A gL/gG fuse. The 20 A recommendation is the one most panel designers spec for selectivity downstream of a motor circuit breaker. Mechanical life is rated at 30 million operating cycles typical. That is the mechanical endurance — electrical life will be lower depending on the switching current and duty cycle, but the mechanical figure gives confidence for high-cycle applications like conveyor indexing or valve actuation.
Where it fits in the panel
Dimensions are 45 mm wide, 57.5 mm high, and 72 mm deep. The 45 mm width is the standard S00 footprint — three of these fit in a 135 mm wide DIN-rail section, which is typical for a small motor control center bucket. Side-by-side mounting is permitted with a 6 mm clearance to adjacent devices, so you can gang them without derating for heat buildup. Degree of protection is IP20 on the front and at the terminals, which is standard for enclosed panel mounting — no finger-safe shrouding needed inside a locked cabinet. Pollution degree 3 means it is rated for conductive pollution environments typical of industrial control rooms, not clean-room or office spaces. Operating ambient temperature range is -25 to +60 °C, with a maximum installation altitude of 2,000 m without derating. That covers most indoor industrial environments, including unheated warehouses in temperate climates.
Sourcing and lifecycle
The reference code per DIN EN 81346-2 is Q, which designates it as a switching device in the functional labeling standard. That is useful for panel documentation and for matching the part to a pre-labeled schematic.