The SIL 3 / PL e rating means this relay can be used in safety functions up to the highest performance level for single-channel architectures — suitable for guarding applications like light curtains, two-hand controls, and emergency stop circuits where the required safety integrity demands a proven component. The safe failure fraction (SFF) of 99 % indicates that over 99 % of dangerous failures are detected by the internal diagnostics, a key figure for achieving SIL 3 without redundancy. The 24 V DC coil is the standard control voltage for industrial safety circuits. The relay includes both a start input and a feedback input, allowing monitored manual or automatic start and external contactor monitoring — typical for E-stop and guard door circuits that need to detect welded contacts downstream. Screw-type terminals accept solid wire 1x (20…14 AWG) or 2x (18…16 AWG), and stranded wire 1x (20…16 AWG) or 2x (20…16 AWG). With ferrule, the range is 1x (0.5…2.5 mm²) or 2x (0.5…1.0 mm²). This covers most panel wiring up to 2.5 mm² without special tools. Shock resistance is 10g / 11 ms, and mounting position is any, giving flexibility in cabinet layout. The maximum operating frequency is 2000 switching cycles per hour.
Siemens 3SK1112-1BB40 SIRIUS Safety Relay, SIL 3/PL e, 24 V
MPN3SK1112-1BB40
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Siemens SIRIUS 3SK1112-1BB40 safety relay, solid-state enabling circuits, SIL 3 / PL e, 24 V DC, screw terminals, 22.5 mm width.
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Independent China distributor & sourcing agent· Listing updated Sep 2026
Specifications
| Parameter | Value |
|---|---|
| Type of electrical connection | screw-type terminals |
| Safety device type according to IEC 61508-2 | Type B |
| Type of electrical connection Plug-In socket | No |
| Type of voltage of the control supply voltage | DC |
| Type of the Safety-Related wiring of the inputs | single-channel and two-channel |
| Insulation voltage rated value | 50 V |
| Surge voltage resistance rated value | 800 V |
| Design of the fuse link for short-circuit protection of the NO contacts of the relay outputs required | not required |
| Power loss [W] maximum | 2 W |
| Recovery time after power failure typical | 6.5 s |
| Operating frequency maximum | 2 000 1/h |
| Protection class IP of the enclosure | IP20 |
All specifications
| Parameter | Value |
|---|---|
| Mounting position | any |
| Installation environment regarding EMC | This product is suitable for Class A environments only. In household environments, this device can cause unwanted radio interference. The user is required to implement appropriate measures in this case. |
| Installation altitude at height above sea level maximum | 4 000 m; Derating, see Product Notification 109792701 |
| Of semiconductor outputs at dc-13 at 24 | 2 A |
| Suitability for operation device connector 3ZY12 | No |
| Shock resistance | 10g / 11 ms |
| EMC emitted interference | IEC 60947-5-1, Class A |
| Relative humidity during operation | 10 ... 95 % |
| Touch protection against electrical shock | finger-safe |
| Vibration resistance according to IEC 60068-2-6 | 5 ... 500 Hz: 0.75 mm |
| Depth | 91.6 mm |
| Width | 22.5 mm |
| Height | 100 mm |
| According to IEC 61508 | 3 |
| According to IEC 62061 | 3 |
| Reference code according to IEC 81346-2 | F |
| Hardware fault tolerance according to IEC 61508 | 1 |
| PFDavg with low demand rate according to IEC 61508 | 7E-6 |
| Solid | 1x (20 ... 14), 2x (18 ... 16) |
| At DC | 0.8 ... 1.2 |
| Typical | 6 500 ms |
| Stranded | 1x (20 ... 16), 2x (20 ... 16) |
| Rated value | 24 V |
| Start input | Yes |
| Safety switch | Yes |
| At DC maximum | 85 ms |
| During storage | -40 ... +80 °C |
| Feedback input | Yes |
| During operation | -25 ... +60 °C |
| Mounting | screw and snap-on mounting |
| Product category | Safety relays |
| Degree of pollution | 3 |
| Overvoltage category | 3 |
| Design of the product | Solid-state enabling circuits |
| Instantaneous contact | 2 |
| Design of the cascading | yes |
| Safety-Related circuits | Yes |
| With core end processing | 1x (0.5 ... 2.5 mm²), 2x (0.5 ... 1.0 mm²) |
| According to ISO 13849-1 | e |
| Of the sensor input minimum | 60 ms |
| Safe failure fraction | 99 % |
| Monitoring of floating sensors | Yes |
| Product function parameterizable | sensor floating / sensor non-floating, monitored start-up / automatic start, 1-channel / 2-channel sensor connection, cross-circuit detection, startup testing |
| Safety-Related delayed switching | 0 |
| Monitoring of Non-Floating sensors | Yes |
| Air pressure according to SN 31205 | 90 ... 106 kPa |
| Of the ON pushbutton input minimum | 0.15 s |
| Product feature Cross-Circuit-Proof | Yes |
| Cascading input (Functional switching) | Yes |
| Safety-Related instantaneous contact | 0 |
| Category according to EN ISO 13849-1 | 4 |
| Stop category according to EN 60204-1 | 0 |
| Magnetically operated switch monitoring | Yes |
| Suitability for interaction press control | No |
| For signaling function instantaneous contact | 1 |
| Number of sensor inputs 1-Channel or 2-Channel | 1 |
| Required spacing for grounded parts at the side | 5 mm |
| PFHD with high demand rate according to EN 62061 | 1E-9 1/h |
| Recovery time after opening of the safety circuits typical | 30 ms |
| Backslide delay time after opening of the safety circuits typical | 40 ms |
Product details
Frequently asked questions
Where can I buy 3SK1112-1BB40 and get a price?
This part is sourced and quoted to order against an RFQ through independent distribution. Submit an RFQ for current availability and pricing — no stock or price figures are published here.
What is the depth of 3SK1112-1BB40?
The depth is 91.6 mm, with a width of 22.5 mm and height of 100 mm.
What solid wire sizes does the 3SK1112-1BB40 accept?
Screw terminals accept solid wire 1x (20…14 AWG) or 2x (18…16 AWG). Stranded wire 1x (20…16 AWG) or 2x (20…16 AWG). With ferrule: 1x (0.5…2.5 mm²) or 2x (0.5…1.0 mm²).
What compliance documentation does Siemens provide for 3SK1112-1BB40?
The relay is certified to IEC 61508 (SIL 3), IEC 62061 (SIL 3), and ISO 13849-1 (PL e). EMC emitted interference meets IEC 60947-5-1, Class A. The product is part of the SIRIUS brand from Siemens.
MPN
3SK1112-1BB40