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Siemens 3RU2126-4CB0-ZW96 — Overload Relays

Siemens 3RU2126-4CB0-ZW96 SIRIUS Thermal Overload Relay, CLA

MPN3RU2126-4CB0-ZW96
Active

Siemens SIRIUS thermal overload relay, 3RU2126-4CB0-ZW96, CLASS 10, S0 size, 690 V rated insulation, contactor mounting.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
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Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RU2126-4CB0-ZW96 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationthermal overload relay
Frame size (overload relay)S0
Combinable contactor sizesS0
Reference code (IEC 81346-2)F
3RU2126-4CB0-ZW96 — Protection & Trip
ParameterValue
Overload current setting range17 ... 22 A
Trip classCLASS 10
Overload release typethermal
3RU2126-4CB0-ZW96 — 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 value (AC-3e), max.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
3RU2126-4CB0-ZW96 — 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
3RU2126-4CB0-ZW96 — Connection & Mounting
ParameterValue
Mounting / fastening methodContactor mounting
Mounting positionany
Main-circuit connector arrangementTop and bottom
Auxiliary/control circuit connection typescrew-type terminals
Removable aux./control terminalNo
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)
3RU2126-4CB0-ZW96 — 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
3RU2126-4CB0-ZW96 — Mechanical
ParameterValue
Width45 mm
Height85 mm
Depth85 mm

Product details

The relay is sized as S0, the compact frame in the SIRIUS family, designed to mount directly onto the matching S0 contactor (e.g. 3RT20xx) via the contactor mounting fastening method — no separate base or DIN-rail adapter needed.

The relay carries motor power ratings at several common line voltages: 11 kW at 400 V, 11 kW at 500 V, and 18.5 kW at 690 V. At 480 V and 600 V the listed current ratings are 22 A each. These are the AC-3e rated values — the duty cycle for starting and running a standard induction motor. If your BOM specifies a 22 A motor at 480 V, this relay covers it. Auxiliary contact ratings are given across multiple control voltages: 2 A at 24 V and 230 V, 3 A at 120 V, 1 A at 400 V, and lower values for 60 V, 110 V, 125 V, and 220 V. These are the switching capacities for the integrated auxiliary switch — the signal that tells the PLC "motor tripped." The note "for message 'Tripped'" on the order code confirms this variant includes a dedicated signaling contact for that status. Thermal power dissipation per pole is 2.7 W. In a densely packed panel with multiple relays, that heat adds up — factor it into your enclosure thermal budget, especially if the ambient inside the cabinet approaches the 70 °C operating limit.

Mounts directly onto the S0 contactor — no separate DIN-rail footprint, no extra wiring between contactor and relay. The fastening method is "contactor mounting": the relay clips onto the contactor's body and the main power connections pass through. Screw-type terminals on the main current circuit accept 2×(0.5…1.5 mm²) or 2×(0.75…2.5 mm²) solid or stranded wire. The screwdriver spec is Pozidriv PZ2, shaft diameter 5–6 mm. Temperature compensation is active from -40 °C to +60 °C, meaning the trip curve stays accurate across that ambient range.

The substance prohibitance date of 10/01/2009 indicates RoHS compliance to the original EU directive. As a current-production Siemens industrial component, it also carries the expected CE, UL, and CSA approvals (typical for the SIRIUS family), though specific cert numbers are not listed in this spec excerpt. For a pharmaceutical GMP application, the documentation package (declaration of conformity, material certificates) should be obtainable from Siemens support.

Frequently asked questions

What does the note 'for message Tripped' on the order code mean?

It means this variant includes an integrated auxiliary switch that provides a dedicated signaling contact specifically for reporting the tripped state of the relay to a PLC or indicator light.

What are the key motor ratings for this relay?

At 400 V and 500 V it is rated for 11 kW motor loads. At 690 V it is rated for 18.5 kW. At 480 V and 600 V the current rating is 22 A. These are AC-3e values for standard induction motor starting and running.

Does this relay mount on a DIN rail or directly on a contactor?

It mounts directly onto a Siemens S0-size contactor via the contactor mounting fastening method. It does not require a separate DIN-rail base.

What compliance documentation is available for this part?

The spec shows a substance prohibitance date of 10/01/2009, confirming RoHS compliance to the original directive. As a current Siemens SIRIUS product, it typically carries CE, UL, and CSA marks, and a declaration of conformity should be available from Siemens.

MPN
3RU2126-4CB0-ZW96