Skip to main content
Siemens 3RU2126-4DB0-ZW96 — Overload Relays

Siemens 3RU2126-4DB0-ZW96 SIRIUS Thermal Overload Relay, Siz

MPN3RU2126-4DB0-ZW96
Active

Siemens SIRIUS thermal overload relay, 3RU2126-4DB0-ZW96, Size S0, Trip Class 10, 690 V rated, screw terminals, contactor mounting, integrated auxiliary switch with tripped message.

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

3RU2126-4DB0-ZW96 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationthermal overload relay
Frame size (overload relay)S0
Combinable contactor sizesS0
Reference code (IEC 81346-2)F
3RU2126-4DB0-ZW96 — Protection & Trip
ParameterValue
Overload current setting range20 ... 25 A
Trip classCLASS 10
Overload release typethermal
3RU2126-4DB0-ZW96 — Electrical (main circuit)
ParameterValue
Rated operational current25 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
3RU2126-4DB0-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
3RU2126-4DB0-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)
3RU2126-4DB0-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
3RU2126-4DB0-ZW96 — Mechanical
ParameterValue
Width45 mm
Height85 mm
Depth85 mm

Product details

It mounts directly to a contactor (fastening method: contactor mounting) and uses a thermal bimetallic release to track the motor's thermal state. The integrated auxiliary switch includes a dedicated "Tripped" message contact, giving the PLC or HMI a hardwired signal that the relay has operated — no separate status module needed.

Trip Class 10 — What That Means for Your Motor

That's the standard for standard-duty induction motors driving pumps, fans, and conveyors — fast enough to prevent winding damage under locked-rotor conditions, but not so fast that it nuisance-trips on normal starting current. For high-inertia loads (flywheels, crushers) you'd typically step up to Class 20; for submersible or hermetically sealed motors, Class 5. This relay is sized for the middle of the curve.

Auxiliary Contact Ratings — Sizing the Signal Side

The integrated auxiliary switch carries different current ratings depending on the control voltage used. At 24 V it's rated 2 A; at 120 V it's 3 A; at 230 V it's 2 A; at 400 V it drops to 1 A. The 60 V and 110–125 V ratings are lower (0.3 A and 0.22 A respectively). This matters when you're feeding a PLC input or a contactor coil — make sure the inrush doesn't exceed the rating at your control voltage. The switch is integrated, so no separate auxiliary block to order, but also no option to upgrade contact material.

Mounting and Integration — Contactor Direct

This relay mounts directly to the contactor — no separate DIN-rail bracket needed, though it can be panel-mounted if the contactor is. The Size S0 footprint is 45 mm wide by 85 mm deep by 85 mm high. Screw terminals on the main circuit accept 2× (0.5…1.5 mm²) or 2× (0.75…2.5 mm²) solid or stranded wire. Pozidriv PZ 2 screwdriver tip with a 5–6 mm shaft diameter is what the panel builder will grab. Mounting position is any, which helps in tight cabinets.

Temperature compensation is active from -40 to +60 °C, meaning the trip curve stays accurate across that span — important for outdoor or unheated enclosures. The substance prohibition date of 10/01/2009 aligns with RoHS compliance; the part carries the SIRIUS brand and is designed to Siemens quality standards. MTTF with high demand rate is 2,280 years — a reliability figure that's more about the semiconductor-level failure rate than field experience, but it passes the bar for most safety-related applications.

Frequently asked questions

What is the 3RU2126-4DB0-ZW96's tripped message contact?

The relay includes an integrated auxiliary switch with a dedicated contact for the "Tripped" message. This gives a hardwired signal when the overload relay has operated, without needing an external status module.

Will 3RU2126-4DB0-ZW96 drop into a panel specified for 3RU2116-1FC1?

Both are Size S0 thermal overload relays with the same mounting method (contactor mounting) and similar footprint (45 mm width). The 3RU2126-4DB0-ZW96 has the integrated tripped message contact which the 3RU2116-1FC1 may lack — check your control wiring for that signal. Otherwise, mechanical fit and terminal layout are the same.

What compliance documentation does this relay carry?

The substance prohibition date of 10/01/2009 indicates RoHS compliance. The SIRUS brand and Siemens design standards mean it meets applicable IEC/EN 60947-4-1 requirements for thermal overload relays, though specific UL/CSA file numbers are not listed in this record.

Where can I buy the 3RU2126-4DB0-ZW96?

This part is sourced to order against an RFQ through independent distribution. Submit a request for current availability and pricing; stock levels and lead time are confirmed at quote time.

MPN
3RU2126-4DB0-ZW96