Glossary · Hazards and harm
Nuisance trip
Also known as: spurious trip, false trip
In machine safety, a nuisance trip is an unwanted protective stop that does not correspond to an actual hazardous demand, for example a light curtain interrupted by a passing part. Frequent nuisance trips can encourage bypassing.
- Machine safety
- Human factors
In one sentence
A nuisance trip is a protective stop without a real hazard; frequent trips cost production time and push people toward defeating safeguards.
Example
On a palletizer, the light curtain at the exit stops the line whenever a pallet passes; muting sensors that distinguish pallets from people end the trips without removing the protection.
How it applies
- Machine safety: Nuisance trips come from poorly matched sensors, misalignment, vibration, dirt, reflections or material flows that cross a protective field. Each one costs production time and teaches people that the device is an obstacle, which can lead to bypass behavior.
- Design: Remove the cause, not the protection: correct positioning, muting for material flow, blanking for fixed objects, and better diagnostics. Muting and blanking change the protective function and must be covered by the risk assessment. Most nuisance trips are a protective device reacting as designed to a situation the application did not anticipate, so the fix usually belongs in design or integration.
- Technical documentation: Troubleshooting sections should list the causes of spurious stops and the permitted remedies, and state clearly that disabling the device is not one of them.
- Evidence: Log trip frequency and causes. A rising rate is operational feedback for change control.