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Siemens 3RU7126-4CB0 — Overload Relays

Siemens 3RU7126-4CB0 SIRIUS Thermal Overload Relay, 22 A, Cl

MPN3RU7126-4CB0

Siemens SIRIUS thermal overload relay, Size S0, 22 A rated current, Trip Class 10, IP20, 3RU7126-4CB0.

Siemens 3RU7126-4CB0 datasheet (PDF)
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

3RU7126-4CB0 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationThermal overload relay
Frame size (overload relay)S0
Combinable contactor sizesS0
3RU7126-4CB0 — Protection & Trip
ParameterValue
Overload current setting range17 ... 22 A
Trip classCLASS 10
Overload release typethermal
3RU7126-4CB0 — Electrical (main circuit)
ParameterValue
Rated operational current22 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)8.1 W
Per pole2.7 W
3RU7126-4CB0 — Auxiliary contacts
ParameterValue
Switching current at 24 V3 A
Switching current at 230 V2 A
3RU7126-4CB0 — 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)
3RU7126-4CB0 — Environmental
ParameterValue
Operating temperature-20 ... +55 °C
Transport temperature-25 ... +70 °C
Relative humidity, operating0 ... 90 %
Max. installation altitude2 000 m
3RU7126-4CB0 — Mechanical
ParameterValue
Width45 mm
Height97 mm
Depth96 mm

Product details

The Siemens 3RU7126-4CB0 is a SIRIUS thermal overload relay in Size S0, rated at 22 A operational current with Trip Class 10 protection. It mounts directly to a Size S0 contactor, making it a drop-in thermal protection element for motor starters in control panels.

The 22 A rated current sets the motor FLA it can protect — size the relay to the motor nameplate, not the contactor. Size S0 frames the physical envelope: 45 mm wide, 97 mm tall, 96 mm deep. It belongs inside an IP54 or higher enclosure, not in a splash zone.

Frequently asked questions

Where can I buy 3RU7126-4CB0 and get a price?

This part is sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.

What are the key ratings of 3RU7126-4CB0?

Rated operational current 22 A, Trip Class 10, Size S0, IP20 front and terminal, operating temperature -20 to +55 °C.

Will 3RU7126-4CB0 drop into a panel specified around 3RU2116-1FC1?

Both are Size S0 overload relays with the same mounting footprint and contactor interface, so the 3RU7126-4CB0 fits the same panel layout without rewiring. The main difference is the current range — verify the 22 A rating matches your motor FLA.

MPN
3RU7126-4CB0