XB4BS8442
Active22mm Complete E-Stop Twist Release 1NC+1NO
Schneider XB4BS8442 — complete emergency stop with 1NC+1NO contacts pre-assembled.
Common Applications
Pre-assembled complete e-stop unit. 1NC for the safety circuit, 1NO for PLC feedback (e-stop pressed signal). One part number, zero assembly. The most specified complete e-stop in Europe.
Specifications
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Actuator Function
Momentary = springs back when released. Maintained/latching = stays pressed until pressed again.
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Twist-release
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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 40mm
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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
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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
1NO + 1NC: One circuit closes and one opens when pressed. Common for start buttons that also signal 'running' state.
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1NC+1NO
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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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IP Rating
IP66: Dust-tight and withstands powerful water jets from any direction. Standard for outdoor and washdown applications.
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IP66
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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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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
$41.63 — $51.79
across 2 distributors
Quick Specs
- Actuator Function
- Twist-release
- Actuator Type
- Mushroom 40mm
- Certifications
- UL, CSA, CE
- Color
- Red
- Contact Configuration
- 1NC+1NO
What People Are Saying
“Pre-assembled complete e-stop unit. 1NC for the safety circuit, 1NO for PLC feedback (e-stop pressed signal). One part number, zero assembly. The most specified complete e-stop in Europe.”
