The Siemens SIRIUS 3UG3521-1AL20 is a 22.5 mm monitoring relay for undercurrent or overcurrent detection, adjustable from 2 to 500 mA AC/DC. It provides a single changeover contact and is powered by AC 230 V 50/60 Hz, with screw terminals and snap-on mounting onto a standard DIN rail.
Siemens SIRIUS 3UG3521-1AL20 Monitoring Relay, Under/Overcur
MPN3UG3521-1AL20
Siemens SIRIUS monitoring relay, 22.5 mm, undercurrent or overcurrent monitoring, 2…500 mA AC/DC, 1 CO contact, AC 230 V 50/60 Hz, screw connection, snap-on mounting.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Specifications
| Parameter | Value |
|---|---|
| Product line / brand name | SIRIUS |
| Parameter | Value |
|---|---|
| Mounting type | snap-on mounting |
| Parameter | Value |
|---|---|
| Removable terminal for main circuit | No |
| Reference code acc. to DIN EN 61346-2 | K |
| Reference code acc. to DIN EN 81346-2 | K |
| Number of poles for main current circuit | 1 |
| Removable terminal for auxiliary and control circuit | No |
Product details
Frequently asked questions
What replaces the 3UG3521-1AL20?
The official replacement is the 3UG4621-1AW30.
What is the mounting type for this relay?
Snap-on mounting onto a 35 mm DIN rail.
What are the key monitoring ranges?
Undercurrent or overcurrent monitoring from 2 to 500 mA AC/DC, with a single CO contact and AC 230 V 50/60 Hz supply.
MPN
3UG3521-1AL20