Out here in the grease, a motor overload relay is what keeps a pump from cooking itself. This 3RU2126-4EB0 is a SIRIUS thermal overload relay, size S0, with a CLASS 10 trip — meaning when the motor pulls too much current for too long, it pops quick enough to save a submersible or a conveyor drive. It's built to ride on a contactor — fastens directly, any position, so you can stuff it into a tight panel. Living on a hot oil pump or a dusty crusher? It's compensated from -40 to +60 °C, and the electronics tolerate -40 to +70 °C during operation. That means it won't drift when the sun bakes the panel. RoHS date of 10/01/2009 is on the nameplate, so it meets the substance restrictions.
Siemens 3RU2126-4EB0 SIRIUS Thermal Overload Relay, CLASS 10
MPN3RU2126-4EB0
Active
Siemens SIRIUS thermal overload relay, size S0, CLASS 10, 690 V, 45 mm width, contactor-mounted, with integrated tripped-signal auxiliary contact.
$45.72Ref. price · indicative, final on quote
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026
Specifications
| Parameter | Value |
|---|---|
| Product brand name | SIRIUS |
| Product designation | thermal overload relay |
| Frame size (overload relay) | S0 |
| Combinable contactor sizes | S0 |
| Reference code (IEC 81346-2) | F |
| Parameter | Value |
|---|---|
| Overload current setting range | 27 ... 32 A |
| Trip class | CLASS 10 |
| Overload release type | thermal |
| Parameter | Value |
|---|---|
| Rated operational current | 32 A |
| Poles (main circuit) | 3 |
| Rated operating frequency | 50 ... 60 Hz |
| Rated insulation voltage (AC, pollution degree 3) | 690 V |
| Rated value (AC-3e), max. | 690 V |
| Rated surge withstand voltage | 6 kV |
| Main current circuit | screw-type terminals |
| Power loss at rated current (hot) | 9.6 W |
| Per pole | 3.2 W |
| Parameter | Value |
|---|---|
| Auxiliary contacts: NO | 1 |
| Auxiliary contacts: NC | 1 |
| Auxiliary contacts: CO (changeover) | 0 |
| Auxiliary switch short-circuit protection (required fuse) | fuse gG: 6 A, quick: 10 A |
| Switching current at 24 V | 2 A |
| Switching current at 60 V | 0.3 A |
| Switching current at 110 V | 0.22 A |
| Switching current at 120 V | 3 A |
| Switching current at 125 V | 0.22 A |
| Switching current at 220 V | 0.11 A |
| Switching current at 230 V | 2 A |
| Switching current at 400 V | 1 A |
| Parameter | Value |
|---|---|
| Mounting / fastening method | Contactor mounting |
| Mounting position | any |
| Main-circuit connector arrangement | Top and bottom |
| Auxiliary/control circuit connection type | screw-type terminals |
| Removable aux./control terminal | No |
| Conductor cross-section: solid or stranded | 2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²) |
| Conductor cross-section: finely stranded with ferrule | 2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²) |
| Conductor range (AWG), main contacts | 2x (16 ... 12), 2x (14 ... 8) |
| Conductor range (AWG), auxiliary contacts | 2x (20 ... 16), 2x (18 ... 14) |
| Parameter | Value |
|---|---|
| Operating temperature | -40 ... +70 °C |
| Storage temperature | -55 ... +80 °C |
| Transport temperature | -55 ... +80 °C |
| Relative humidity, operating | 10 ... 95 % |
| Max. installation altitude | 2 000 m |
| Parameter | Value |
|---|---|
| Width | 45 mm |
| Height | 85 mm |
| Depth | 85 mm |
Product details
Frequently asked questions
What is the trip class of this overload relay?
Trip class is CLASS 10, which provides fast tripping for motors that need protection against rapid overheating.
What mounting options does this relay have?
It fastens directly onto a contactor (contactor mounting) and can be mounted in any position.
What operating temperature range does it support?
During operation it is rated from -40 to +70 °C, with temperature compensation from -40 to +60 °C.
MPN
3RU2126-4EB0