The 3UG3521-1AC40: The 22.5 mm width and snap-on mounting onto a 35 mm DIN rail (DIN EN 50022) match the standard footprint for monitoring relays in control panels. The non-removable screw terminals mean wiring is done in-place; plan for tool access above and below the unit.
Siemens 3UG3521-1AC40 SIRIUS Monitoring Relay, 24 VDC, 2–500
MPN3UG3521-1AC40
Siemens SIRIUS discontinued-type monitoring relay, 22.5 mm, snap-on mounting, over/undercurrent monitor 2–500 mA AC/DC, 1 CO contact, 24 VDC, screw connection.
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 is the mounting type for the 3UG3521-1AC40?
Snap-on mounting onto a 35 mm standard mounting rail per DIN EN 50022. The housing width is 22.5 mm.
What are the key ratings of the 3UG3521-1AC40?
It monitors over/undercurrent from 2 to 500 mA AC/DC, has a 24 VDC control supply, and switches one CO contact via screw terminals.
MPN
3UG3521-1AC40