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Siemens 3RU2126-4EC1 — Overload Relays

Siemens 3RU2126-4EC1 SIRIUS thermal overload relay, CLASS 10

MPN3RU2126-4EC1
Active

Siemens SIRIUS thermal overload relay, 3RU2126-4EC1, CLASS 10, rated 690 V, size S0, spring-loaded terminals.

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

3RU2126-4EC1 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationthermal overload relay
Frame size (overload relay)S0
Combinable contactor sizesS0
Reference code (IEC 81346-2)F
3RU2126-4EC1 — Protection & Trip
ParameterValue
Overload current setting range27 ... 32 A
Trip classCLASS 10
Overload release typethermal
3RU2126-4EC1 — Electrical (main circuit)
ParameterValue
Rated operational current32 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 circuitspring-loaded terminals
Power loss at rated current (hot)9.6 W
Per pole3.2 W
3RU2126-4EC1 — 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
3RU2126-4EC1 — Connection & Mounting
ParameterValue
Mounting / fastening methodstand-alone installation
Mounting positionany
Main-circuit connector arrangementTop and bottom
Auxiliary/control circuit connection typespring-loaded terminals
Removable aux./control terminalNo
Conductor cross-section: solid or stranded2x (0.5 ... 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 contacts1x (18 ... 8)
Conductor range (AWG), auxiliary contacts2x (20 ... 14)
3RU2126-4EC1 — 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
3RU2126-4EC1 — Mechanical
ParameterValue
Width45 mm
Height114 mm
Depth95 mm

Product details

Rated for 690 V, it covers most 400 V and 690 V industrial supply systems. The relay mounts stand-alone or onto a SIRIUS contactor, and the spring-loaded terminals on the main circuit accept 2x (0.5... 2.5 mm²) solid or stranded wire, so panel wiring is tool-less for the power connections.

Trip class and thermal design — what CLASS 10 means for the motor

CLASS 10 is the standard trip class for general-purpose squirrel-cage motors. It coordinates with a contactor to clear a locked-rotor condition before the motor winding temperature exceeds its insulation class. The thermal overload release is bimetallic, temperature-compensated from -40 to +60 °C, so ambient shifts in the panel do not shift the trip point. Per-pole power dissipation is 3.2 W, which matters when grouping multiple relays in a small enclosure — derating may be needed if the internal ambient climbs above 40 °C.

The relay is size S0, with a width of 45 mm, height 114 mm, and depth 95 mm. It can be installed in any mounting position — no derating required for side or inverted orientation. The auxiliary switch is integrated, so no separate add-on block is needed for the trip/alarm signal. The screwdriver shaft for the terminal screws is 3 mm diameter, tip size 3.0 x 0.5 mm. For the auxiliary circuit, the relay carries ratings across common control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and 0.75 A at 690 V.

Frequently asked questions

What does the note 'for message Tripped' mean?

The note indicates that the auxiliary contact configuration is wired to signal a 'Tripped' status — typically the normally-open contact closes when the relay trips from an overload or phase failure.

What compliance documentation is available?

The relay carries a substance prohibitance date of 10/01/2009, indicating RoHS compliance per EU Directive 2002/95/EC. As a SIRIUS product, it is designed to meet IEC and UL standards, but specific certification marks (UL, CSA, CE) should be confirmed on the nameplate or via the manufacturer's declaration.

MPN
3RU2126-4EC1