The four safety edges on a typical UK platform lift
- Under-platform pressure switch. A sensing surface on the underside of the platform that trips if the platform meets any obstruction on the way down.
- Top-edge trip. A bar or ridge above the platform that trips if a rising platform meets an obstruction.
- Toe-guard trip. On step lifts, the vertical toe guard that stops shoes being caught in the gap between platform and adjacent stair.
- Ramp / loading-edge sensor. Trips if the loading ramp isn't fully raised before travel.
The controller will log which edge tripped — get the message from the display before you do anything else.
Common under-platform trips
The commonest cause on outdoor UK platform lifts is leaves, packaging or snow building up under the platform, so the pressure switch trips as it rises off the bottom landing. Look, don't reach — clear the debris with a broom, not a hand, then reset the lift from the top landing using the hold-to-run button.
Safe to check yourself
Indoor platform lifts can trip on: a pet under the platform, a shoe left on the landing, a delivery box the postman put beside the loading ramp.The pressure switch itself failing
The under-platform sensor can fail over time, especially on outdoor lifts exposed to weather. Symptom: repeated trips on an obviously clear landing. Do not clean the sensor with anything wet; do not attempt to bypass or adjust it. This is a service call — the sensor is a routine wear part on outdoor lifts and gets replaced every 5–10 years depending on exposure.
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Describe your symptom →Toe-guard trips on step lifts
Step lifts (which give a wheelchair access up 5–8 stairs) have a vertical toe guard that trips if anyone's foot or a walking stick is caught in the platform-to-stair gap. Symptom: the lift stops the instant it starts to move. Look at the stair-side edge and remove the obstruction; if none is visible, the guard sensor has drifted and needs an engineer.
Ramp not fully raised
The loading ramp on a platform lift must be fully raised before the lift will start. If the mechanism is stiff, or the ramp has been knocked, it can look raised but not have activated the sensor. Push the ramp firmly to home, listen for the click, then try again. Repeat trips at this stage indicate the sensor or the ramp latch is failing.
When a safety-edge trip means STOP
Stop — call an engineer
Do not reset and retry more than twice if:
- The trip is on the top edge with a person or pushchair on the platform — the top of the shaft may have shifted or the platform may be over-travelling.
- You can see damage to any sensor cable or bracket.
- The lift has hit an obstruction hard enough to make a bang — structural inspection needed before further use.
- The trip is intermittent and getting more frequent over days — the sensor is failing.
Frequently asked questions
- Can I disable the safety edge to complete a trip?
- Absolutely not. The safety edge is a life-safety device. Disabling it is a criminal offence for workplace lifts under LOLER and voids the CE marking of any UK platform lift.
- The lift trips every time it rains. What's happening?
- Water is bridging the under-platform sensor contacts and simulating a pressure event. This is a known failure mode on some outdoor lifts and is fixed by replacing the sensor with a weather-sealed version at service.
- The trip is only on one direction. Why?
- Different sensors fire in different directions — down-travel uses the under-platform sensor, up-travel uses the top edge. A one-direction fault localises the problem for the engineer instantly.
- How do I reset after a safety-edge trip?
- On most UK platform lifts, moving the platform in the opposite direction from the parking landing clears the fault. Some models require a service key reset if the trip repeats within a short window.
- Is a safety-edge trip logged for LOLER purposes?
- The controller logs every trip and the annual thorough examination reviews the log. Repeated trips without a clear physical cause are a common reason for a ‘defect noted’ entry on the LOLER report.