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Siemens 3RU6126-4PB0 — Overload Relays

Siemens 3RU6126-4PB0 SIRIUS Thermal Overload Relay, 30-36 A,

MPN3RU6126-4PB0

Siemens SIRIUS 3RU6126-4PB0 thermal overload relay, 30-36 A adjustable, Class 10, size S0, screw terminals, for motor protection.

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

Specifications

3RU6126-4PB0 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationThermal overload relay
Combinable contactor sizesS0
3RU6126-4PB0 — Protection & Trip
ParameterValue
Overload current setting range30 ... 36 A
Trip classCLASS 10
Overload release typethermal
3RU6126-4PB0 — Electrical (main circuit)
ParameterValue
Rated operational current36 A
Poles (main circuit)3
Rated operating frequency50 ... 60 Hz
Rated insulation voltage (AC, pollution degree 3)690 V
Rated surge withstand voltage6 kV
Main current circuitscrew-type terminals
Power loss at rated current (hot)9.6 W
Per pole3.2 W
3RU6126-4PB0 — Auxiliary contacts
ParameterValue
Switching current at 24 V2 A
Switching current at 110 V0.22 A
Switching current at 230 V2 A
3RU6126-4PB0 — Connection & Mounting
ParameterValue
Mounting / fastening methodContactor mounting
Mounting positionany
Main-circuit connector arrangementTop and bottom
Auxiliary/control circuit connection typescrew-type terminals
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 (16 ... 12), 2x (14 ... 8)
Conductor range (AWG), auxiliary contacts2x (20 ... 16), 2x (18 ... 14)
3RU6126-4PB0 — Environmental
ParameterValue
Operating temperature-40 ... +70 °C
Transport temperature-55 ... +80 °C
Relative humidity, operating0 ... 90 %
Max. installation altitude2 000 m
3RU6126-4PB0 — Mechanical
ParameterValue
Width45 mm
Height85 mm
Depth85 mm

Product details

The Siemens SIRIUS 3RU6126-4PB0 is a thermal overload relay adjustable from 30 to 36 A, rated for 690 V at 50/60 Hz. It is Class 10, size S0, and mounts onto a contactor.

The relay uses screw-type terminals for both the main circuit and the auxiliary/control circuit. Main terminals accept 2× (0.5…1.5 mm²) solid or stranded, or 2× (0.75…2.5 mm²) — torque to 2…2.5 N·m. Auxiliary terminals take 2× (0.5…1.5 mm²) or 2× (0.75…2.5 mm²) as well. The contactor-mounting fastening method means it clips onto the contactor without extra DIN-rail space; spacing to grounded parts at the side is 6 mm.

Shock resistance per IEC 60068-2-27 is 8g for 11 ms. Installation altitude is limited to 2 000 m above sea level. The relay carries a substance prohibitance date of 05/01/2012, indicating RoHS compliance per the EU directive.

Frequently asked questions

What is the closest functional second-source or cross-reference?

The 3RU6126-4PB0 is designed to mount directly onto a size S0 contactor such as the 3RT1036-1AB00. It shares the same frame size, screw-terminal pattern, and Class 10 trip curve, so it drops into a panel wired for that contactor without rewiring the main circuit.

What are the key ratings for this overload relay?

Adjustable current range is 30 to 36 A. Trip class is Class 10. Rated operational current is 36 A at 690 V, 50/60 Hz. Power loss at rated current in hot operating state is 9.6 W per pole.

MPN
3RU6126-4PB0