Siemens 3RB3123-4NE0 SIRIUS Solid-State Overload Relay, 1.25
Siemens SIRIUS solid-state overload relay, 3RB3123-4NE0, S0 size, 1.25 A thermal current, adjustable trip class 5E/10E/20E/30E, 690 V rated, contactor mounting.
Specifications
| Parameter | Value |
|---|---|
| Product brand name | SIRIUS |
| Product designation | solid-state overload relay |
| Frame size (overload relay) | S0 |
| Combinable contactor sizes | S0 |
| Reference code (IEC 81346-2) | F |
| Parameter | Value |
|---|---|
| Overload current setting range | 0.32 ... 1.25 A |
| Trip class | CLASS 5E, 10E, 20E and 30E adjustable |
| Overload release type | electronic |
| Parameter | Value |
|---|---|
| Rated operational current | 1.25 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 | spring-loaded terminals |
| Power loss at rated current (hot) | 0.1 W |
| Per pole | 0.03 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 |
| Switching current at 24 V | 2 A |
| Switching current at 60 V | 0.55 A |
| Switching current at 110 V | 0.3 A |
| Switching current at 120 V | 4 A |
| Switching current at 125 V | 0.3 A |
| Switching current at 220 V | 0.11 A |
| Switching current at 230 V | 3 A |
| Parameter | Value |
|---|---|
| Mounting / fastening method | Contactor mounting |
| Mounting position | any |
| Main-circuit connector arrangement | Top and bottom |
| Auxiliary/control circuit connection type | spring-loaded terminals |
| Removable aux./control terminal | Yes |
| Conductor cross-section: solid | 2x (0.25 ... 1.5 mm²) |
| Conductor cross-section: solid or stranded | 2x (0,25 ... 1,5 mm²) |
| Conductor cross-section: finely stranded with ferrule | 2x (0.25 ... 1.5 mm²) |
| Conductor range (AWG), auxiliary contacts | 1x (24 ... 16), 2x (24 ... 16) |
| Parameter | Value |
|---|---|
| Operating temperature | -25 ... +60 °C |
| Storage temperature | -40 ... +80 °C |
| Transport temperature | -40 ... +80 °C |
| Relative humidity, operating | 10 ... 95 % |
| Max. installation altitude | 2 000 m |
| Shock resistance | 15g / 11 ms |
| Parameter | Value |
|---|---|
| Width | 45 mm |
| Height | 109 mm |
| Depth | 85 mm |
Product details
Frequently asked questions
Where can I buy 3RB3123-4NE0 and how do I get a price?
This part is sourced to order through our independent distribution channel. Submit an RFQ; availability and current pricing are confirmed at quote time.
What is the note 'for message tripped' on this relay?
The note indicates that the signaling contact (terminals 97/98) changes state when the relay trips, providing a dry-contact message to a PLC or indicator.
What is the depth of 3RB3123-4NE0?
The depth is 85 mm, measured from the contactor mounting face.
Will 3RB3123-4NE0 drop into a panel specified for 3RT1016-2AP02?
Both are S0-size contactor-mounted devices from the SIRIUS family, so the physical fit and mounting pattern are the same. The 3RT1016-2AP02 is a contactor; the 3RB3123-4NE0 is its matching overload relay — they are designed to mate directly.
SIRIUS 3RB3123-4NE0 — Solid-State Overload Relay, S0 Size
The Siemens 3RB3123-4NE0 is a SIRIUS solid-state overload relay in the S0 frame size, rated for a thermal current of 1.25 A at 480 V and 600 V, with a maximum rated voltage of 690 V. It mounts directly onto a contactor via the fastening method, saving panel space — no separate base needed. The trip class is adjustable across CLASS 5E, 10E, 20E, and 30E, so you match the relay to the motor start profile: fast trip for short acceleration, slow for high-inertia loads. The note on this unit reads "for message 'tripped'", which is the signaling contact output — it closes when the relay trips, feeding a discrete input on the PLC or annunciator. The auxiliary contact ratings cover common control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.3 A at 125 V, so it interfaces directly with 24 VDC or 120 VAC control circuits without an interposing relay.
Mounting and Wiring — Contactor-Mounted, S0 Footprint
The 3RB3123-4NE0 is designed for contactor mounting (fastening method: contactor mounting), meaning it clips onto the matching S0 contactor — no DIN rail required, though the assembly itself can be snapped onto a DIN rail if needed. Dimensions: 45 mm wide, 109 mm high, 85 mm deep. That 85 mm depth is the projection from the contactor face; account for it in enclosure depth when the panel door closes. Main circuit terminals are spring-loaded terminals accepting solid 2x (0.25... 1.5 mm²) or stranded up to 1x 10 mm². The screwdriver spec calls for Pozidriv PZ 2 with a shaft diameter of 5 to 6 mm. Mounting position is any — no restriction on orientation.
Storage and transport range is -40 to +80 °C. Shock resistance is 15g / 11 ms per IEC 60068-2-27; the signaling contact in the tripped position is rated at 9g / 11 ms. Vibration resistance: 1-6 Hz, 15 mm amplitude; 6-500 Hz, 20 m/s², 10 cycles. Power dissipation per pole is 0.03 W — negligible heat contribution inside the enclosure, so no derating for adjacent relays in a dense panel.