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Siemens 3RU7126-1FB0 — Overload Relays

Siemens 3RU7126-1FB0 SIRIUS Thermal Overload Relay, CLASS 10

MPN3RU7126-1FB0

Siemens SIRIUS thermal overload relay, size S0, CLASS 10, 3-pole, rated operational current 5 A, 690 V, screw terminals.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RU7126-1FB0 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationThermal overload relay
Frame size (overload relay)S0
Combinable contactor sizesS0
3RU7126-1FB0 — Protection & Trip
ParameterValue
Overload current setting range3.5 ... 5 A
Trip classCLASS 10
Overload release typethermal
3RU7126-1FB0 — Electrical (main circuit)
ParameterValue
Rated operational current5 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)6.6 W
Per pole2.2 W
3RU7126-1FB0 — Auxiliary contacts
ParameterValue
Switching current at 24 V3 A
Switching current at 230 V2 A
3RU7126-1FB0 — Connection & Mounting
ParameterValue
Mounting / fastening methodContactor mounting
Mounting positionwith vertical mounting surface +/-135° rotatable, with vertical mounting surface +/- 45° tiltable to the front and back
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)
3RU7126-1FB0 — Environmental
ParameterValue
Operating temperature-20 ... +55 °C
Transport temperature-25 ... +70 °C
Relative humidity, operating0 ... 90 %
Max. installation altitude2 000 m
3RU7126-1FB0 — Mechanical
ParameterValue
Width45 mm
Height97 mm
Depth96 mm

Product details

The Siemens 3RU7126-1FB0 is a SIRIUS thermal overload relay, size S0, designed for 3-pole motor protection. It mounts directly to a matching contactor — the fastening method is contactor mounting, and it's sized to combine with S0 contactors in the same family.

Key ratings for the BOM line

Rated operational current is 5 A, with a rated operating voltage of 690 V AC/DC at 50/60 Hz. The auxiliary contacts are rated at 24 V 3 A and 230 V 2 A.

Mounts on a vertical surface with ±135° rotation and ±45° tilt forward/back. The enclosure is IP20 at the front and terminals. Operating temperature range is -20 to +55 °C, storage -25 to +70 °C, with humidity up to 90%. Installation altitude is limited to 2000 m. Shock resistance per IEC 60068-2-27 is 8g for 11 ms.

Frequently asked questions

What are the key dimensions of the 3RU7126-1FB0?

Width is 45 mm, height 97 mm, depth 96 mm. These are the envelope dimensions for panel layout.

What is the trip class of this overload relay?

It is CLASS 10, meaning the relay trips within 10 seconds at 7.2× the current setting — suited for standard motor starting duty.

What contactor size does this relay mate with?

It is size S0 and is designed for contactor mounting with S0 contactors in the SIRIUS family.

MPN
3RU7126-1FB0