The Siemens 3UG4511-2BN20 is a SIRIUS phase monitoring relay — one function, one output, no asymmetry detection. It monitors a single three-phase AC supply for phase loss or phase sequence reversal, and it does that one job without extra bells. The rated voltage range is 160 to 260 VAC at both 50 and 60 Hz, so it covers common 208/240 V industrial feeds. The output relay is rated 3 A at 250 V or 400 V (50/60 Hz), which is enough to signal a PLC input or drop out a contactor coil. The LED display version gives a quick visual on relay state and supply presence.
Siemens 3UG4511-2BN20 SIRIUS Phase Monitoring Relay, 160-260
MPN3UG4511-2BN20
NRND
Siemens SIRIUS phase monitoring relay, 3UG4511-2BN20, 160-260 VAC 50/60 Hz, 3 A rated contact, IP20, snap-on DIN rail mounting.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Specifications
| Parameter | Value |
|---|---|
| Product function | Phase monitoring relay |
| Product line / brand name | SIRIUS |
| Parameter | Value |
|---|---|
| Rated value (50 Hz) | 160 ... 260 V |
| Rated value (60 Hz) | 160 ... 260 V |
| Parameter | Value |
|---|---|
| Electrical connection type | spring-loaded terminals |
| Parameter | Value |
|---|---|
| Ingress protection (IP rating), wired | IP20 |
| Installation altitude, max. | 2 000 m |
| Parameter | Value |
|---|---|
| Fastening method | snap-on mounting |
| Mounting position | any |
| Width | 22.5 mm |
| Height | 94 mm |
| Depth | 91 mm |
| Conductor cross-section, solid | 24 ... 16 |
| Conductor cross-section, finely stranded (with ferrule) | 0.25 ... 1.5 mm² |
| Mounting clearance, top | 0 mm |
| Mounting clearance, rear | 0 mm |
| Mounting clearance, side | 0 mm |
| Mounting clearance, front | 0 mm |
Product details
Frequently asked questions
What is the voltage range and contact rating?
The monitoring input is rated 160 to 260 VAC at 50/60 Hz. The output relay contacts are rated 3 A at 250 V or 400 V (50/60 Hz), and also 1 A at 24 V, 0.2 A at 125 V, 0.1 A at 250 V for DC loads.
Does it detect phase asymmetry or undervoltage?
No. This relay monitors phase loss and phase sequence only. Asymmetry detection, overvoltage detection, and undervoltage detection are not included.
What mounting and environmental ratings does it have?
Snap-on mounting to 35 mm DIN rail, 22.5 mm wide. IP20 protection, pollution degree 3. Operating temperature -25 to +60 °C, storage/transport -40 to +85 °C.
MPN
3UG4511-2BN20