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Siemens 3RU2146-4LB1 — Overload Relays

Siemens 3RU2146-4LB1 SIRIUS thermal overload relay, CLASS 10

MPN3RU2146-4LB1
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Siemens SIRIUS 3RU2146-4LB1 thermal overload relay, CLASS 10, S3 frame, 45 kW at 400 V, 690 V rated insulation, screw terminals.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RU2146-4LB1 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationthermal overload relay
Frame size (overload relay)S3
Combinable contactor sizesS3
Reference code (IEC 81346-2)F
3RU2146-4LB1 — Protection & Trip
ParameterValue
Overload current setting range70 ... 90 A
Trip classCLASS 10
Overload release typethermal
3RU2146-4LB1 — Electrical (main circuit)
ParameterValue
Rated operational current90 A
Poles (main circuit)3
Rated operating frequency50 ... 60 Hz
Rated insulation voltage (AC, pollution degree 3)1 000 V
Rated value (AC-3e), max.1 000 V
Rated surge withstand voltage8 kV
Main current circuitscrew-type terminals
Power loss at rated current (hot)21 W
Per pole7 W
3RU2146-4LB1 — Auxiliary contacts
ParameterValue
Auxiliary contacts: NO1
Auxiliary contacts: NC1
Auxiliary contacts: CO (changeover)0
Auxiliary switch short-circuit protection (required fuse)fuse gG: 6 A, quick: 10 A
Switching current at 24 V2 A
Switching current at 60 V0.3 A
Switching current at 110 V0.22 A
Switching current at 120 V3 A
Switching current at 125 V0.22 A
Switching current at 220 V0.11 A
Switching current at 230 V2 A
Switching current at 400 V1 A
3RU2146-4LB1 — Connection & Mounting
ParameterValue
Mounting / fastening methodstand-alone installation
Mounting positionany
Main-circuit connector arrangementTop and bottom
Auxiliary/control circuit connection typescrew-type terminals
Removable aux./control terminalNo
Conductor cross-section: solid2x (2.5 ... 16 mm²)
Conductor cross-section: solid or stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor cross-section: finely stranded with ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor range (AWG), main contacts2x (10 ... 1/0), 1x (10 ... 2/0)
Conductor range (AWG), auxiliary contacts2x (20 ... 16), 2x (18 ... 14)
3RU2146-4LB1 — Environmental
ParameterValue
Operating temperature-40 ... +70 °C
Storage temperature-55 ... +80 °C
Transport temperature-55 ... +80 °C
Relative humidity, operating10 ... 95 %
Max. installation altitude2 000 m
3RU2146-4LB1 — Mechanical
ParameterValue
Width70 mm
Height120 mm
Depth140 mm

Product details

RoHS compliance date is March 1, 2017 — the part meets the EU substance restrictions that went into effect that year.

Mounts stand-alone in any position — no orientation restrictions — with screw-type terminals on the main circuit accepting 2x (2.5…16 mm²) solid or 2x (6…16 mm²) stranded, plus larger cable up to 1x 70 mm² stranded on the load side. The auxiliary contact block uses smaller terminals: 2x (0.5…1.5 mm²) solid or 2x (0.75…2.5 mm²) stranded, with a hexagonal socket screwdriver tip (4 mm hex) for the main terminals. Depth of 140 mm, width 70 mm, height 120 mm — fits standard S3 panel cutouts and leaves clearance for wiring ducts.

The integrated auxiliary switch is rated for a range of control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and lower currents at 60 V (0.3 A), 110 V (0.22 A), 125 V (0.22 A), and 220 V (0.11 A) — covering common PLC and relay coil loads across global control voltages.

Frequently asked questions

What does the 'for message Tripped' note mean on this component?

The note indicates the relay provides a dedicated signal contact that changes state when the overload has tripped — used to trigger an alarm or PLC input on a motor fault.

What is the depth of the 3RU2146-4LB1?

The depth is 140 mm, with a width of 70 mm and height of 120 mm.

What compliance documentation does Siemens provide for 3RU2146-4LB1?

RoHS compliance is confirmed with a substance prohibitance date of March 1, 2017. The part is designed to IEC/EN 60947-4-1 standards for motor protection.

MPN
3RU2146-4LB1