3SU1150-1HB20-1CH0
ActiveSIRIUS ACT Red Mushroom Emergency Stop (Push-Pull)
Red 40mm mushroom head emergency stop, Siemens SIRIUS ACT series. Push-pull reset, 22mm cutout, IP66/IP69K.
Common Applications
Siemens emergency stop rated for safety-critical applications. The 40mm mushroom with twist-to-release meets EN/ISO 13850. Found on Siemens robot cells, CNC machine tools (Siemens SINUMERIK-controlled), and automotive assembly lines. When used with Siemens safety PLCs (F-series S7-1500F), this e-stop feeds into the safety program for SIL 3 rated emergency stop circuits. The yellow backing plate (sold separately as 3SU1900-0AB31) provides the required contrast per EN 60947-5-5.
Commonly Found On
Specifications
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Actuator Type
The button head style. Flush sits level with the bezel (prevents accidental presses). Extended protrudes for easy access.
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Mushroom Head
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Certifications
Third-party safety certifications. UL = required for US NEC installations. CE = EU compliance. CSA = Canadian standards.
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UL, CSA, CE, IEC 60947-5-5
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Color
Button/actuator color. Green = start/go, Red = stop/emergency, Yellow = caution, Blue = reset (per IEC 60204-1).
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Red
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Contact Configuration
Normally Closed — circuit is on until you press. Standard for stop/emergency functions. Wire in series with safety circuits.
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1NC
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Cutout Diameter
The hole size you drill in your panel to mount this button. 22mm is the most common industrial standard worldwide.
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22mm
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Head diameter
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40mm
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IP Rating
IP69K: Dust-tight and withstands high-pressure, high-temperature steam jets. Built for food processing washdown environments.
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IP66/IP69K
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Material
The bezel/body material. Metal bezels are more durable in harsh environments. Plastic is lighter and cheaper.
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Metal
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Mounting Type
How the button attaches to the panel. Panel mount is standard — installs through a cutout from the front.
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Panel
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Reset type
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Push-Pull
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You'll Also Need
This is a modular component. For a complete assembly, you may also need:
Compatible Alternatives
These products are functionally equivalent cross-references from other manufacturers.
Installation Quick Reference
Panel cutout: 22mm. Mount with the yellow backing plate visible (required by EN/ISO 13850).
Wiring: Wire NC contacts in series with the safety relay input channels. Use dual-channel wiring for SIL 3 / PLe applications. Never wire directly to a motor contactor.
Testing: Press the e-stop and verify the machine stops within the required time. Test the reset mechanism. Repeat monthly per EN/ISO 13850.
Dimensions
Wiring Diagram
Troubleshooting
E-stop won't reset (twist/pull doesn't release)
Check for debris in the mechanism. For twist-release: turn clockwise 45-90 degrees. For push-pull: pull straight out firmly. If the mechanism is stuck, the internal latch may be damaged — replace the entire head assembly.
Machine doesn't stop when e-stop is pressed
Critical safety issue. Immediately lock out the machine. Check wiring — NC contacts must be in series with the safety relay. Verify the safety relay is functioning. A broken wire in an NC circuit should cause a stop, so check for a wiring bypass.
Safety relay faults after e-stop reset
The safety relay detects a cross-fault between the two monitoring channels. Check that both NC contacts on the e-stop are switching simultaneously. One contact may be welded closed — replace the contact block.
Where to Buy
Price range
$5.86 — $80.84
across 4 distributors
Quick Specs
- Actuator Type
- Mushroom Head
- Certifications
- UL, CSA, CE, IEC 60947-5-5
- Color
- Red
- Contact Configuration
- 1NC
- Cutout Diameter
- 22mm
What People Are Saying
“Running Siemens 3SU1150 e-stops on our bread line for over a year. They get hit with 80C caustic wash daily and still function perfectly. The twist-release mechanism hasn't degraded at all. Wouldn't go back to cheaper alternatives in this environment.”
Learn More
Data Sources
Specifications and product data sourced from the following references.
Siemens 3SU1150-1HB20-1CH0 Product Page
https://sieportal.siemens.com/en-ww/products-services/detail/3SU11501HB201CH0
Accessed March 29, 2026
