SIEMENS
SIEMENS 3RH21221BB40 Control Relay 2NO/2NC 24V DC 10 A
IEC control relay with 2NO/2NC contacts, 24 V DC coil and 10 A rating for DIN rail or surface mounting
- IEC-standard relay integrates with 3RH21 series control panels
- 2 NO and 2 NC contacts switch both AC and DC loads
- 24 V DC coil voltage matches common automation power supplies
- 10 A at 24 V DC handles motor-starting currents directly
- Screw terminals and DIN-rail mounting simplify cabinet wiring
IEC Control Relay for 24 V DC systems
This SIEMENS 3RH21221BB40 relay provides 2 normally open and 2 normally closed contacts rated at 10 A. It is built for control circuits that switch up to 690 V AC or 600 V DC in industrial panels.
DIN rail or surface mount with screw terminals
The S00 frame snaps onto standard DIN rail or fixes with screws using the supplied mounting points. Screw terminals accept solid or stranded wire; overtightening can strip the terminal block and loose wires cause intermittent contact.
Contact ratings define the practical limits
At 24 V DC the contacts carry the full 10 A, but at 600 V DC the rating drops to 0.15 A and at 690 V AC to 1 A. The 4 W coil draws modest power, yet the IP20 housing and 140 °F maximum temperature restrict use to protected enclosures.
Highlights
- IEC-standard relay integrates with 3RH21 series control panels
- 2 NO and 2 NC contacts switch both AC and DC loads
- 24 V DC coil voltage matches common automation power supplies
- 10 A at 24 V DC handles motor-starting currents directly
- Screw terminals and DIN-rail mounting simplify cabinet wiring
Specifications
| Brand | SIEMENS |
|---|
Questions about this item
How can I confirm the relay is operating correctly after wiring it to a 24 V DC supply?
Apply 24 V DC to the coil and verify the contacts switch; the coil draws 4 W and the relay is rated for 10 A at 24 V DC on the NO/NC contacts.
What accessories are included and what must be sourced separately for DIN-rail installation?
The relay body with screw terminals is supplied; DIN-rail clips and any wiring ferrules or jumpers are not included and must be purchased separately.
Which contact rating should I use when selecting this relay for a 240 V AC load?
At 240 V AC the contacts are rated for 10 A, so choose this version when your load does not exceed that current at 240 V AC.
Also in this aisle
People compared these
Same shelf, same checkout — eight coins and a 30-minute rate lock.
