Tumble dryer will occasionally cause the trip switch to blow. we can not the put the power back on till we have switched dryeroff at socket

The breaker box in the unit may not have the rated breaker for your appliance. Most likely.

Have them check it out.

If your Logik LVD7W15 tumble dryer is tripping the fuse box as soon as you close the door, it may be caused by a few different issues. Here are a few steps you can try to troubleshoot the problem:

1. Check the door switch: The door switch is responsible for detecting whether the door is closed or open. If it is not functioning correctly, it can cause the dryer to trip the fuse box. Make sure the door switch is properly installed and functioning.
2. Check the thermal fuse: The thermal fuse is a safety device that is designed to protect the dryer from overheating. If the thermal fuse is faulty, it can cause the dryer to trip the fuse box.
3. Check the heating element: If the heating element is faulty, it can cause the dryer to overheat and trip the fuse box.
4. Check the wiring: Make sure all the wiring connections are tight and secure. Look for any damaged or frayed wires.
5. Check the PCB: The PCB (Printed Circuit Board) controls the various functions of the dryer. If it is faulty, it can cause the dryer to trip the fuse box.
6. If none of the above steps work, it is possible that the dryer has a more serious problem that requires professional service.

Please make sure to turn off the dryer and unplug it before attempting any troubleshooting steps. It is also important to refer to the user manual or contact the manufacturer for specific instructions or troubleshooting steps for your specific model.

Nothing works or drum fails to turn (tumble dryers)
Ensure that the power supply to the dryer is switched on, the timer is set to the desired drying time and the door is correctly closed. If you have a condenser model, also check that the bottle is empty and is fully pushed into the machine.
http://www.whiteknightrange.co.uk/whiteknight/faq.html

The first thing to establish when troubleshooting the clothes dryer is whether the dryer will start or not. If it won't, start by checking the outlet and the circuit breaker. Is the dryer plugged in or has it tripped the circuit breaker? If the breaker has been tripped, flip it back on and try the dryer again. The drum should turn without a problem.
If both plug and breaker are fine, you'll need to inspect the door switch as you continue to troubleshoot the tumble dryer. When you close the door on the dryer, a plastic peg should click and operate the switch which allows the dryer to work. The peg might be bent or broken, in which case it won't connect with the switch. You can try to straighten the peg, but if it's broken, you'll need to replace it. If the peg is fine, the switch has probably failed and will need to be replaced.
http://www.doityourself.com/stry/troubleshooting-a-clothes-dryer-drum-doesnt-tumble#b#ixzz3FOOQgtAT

Good luck!

How to Replace A White Knight Tumble Dryer Heating Element Heater and Thermostat

For a full list of appliance Video Repair help see our video section
White knight tumble dryer not heating this video show you how to change and fit a new heating element and thermostats can be used on Ariston, Electrolux, Ignis, Neutral, Tricity Bendix, Whirlpool,
Here is the element in this video
For all you tumble dryer spare parts click here

The easiest way to find you part is put your model number into our search bar at http://www.apart4u.co.uk/ TEL 08455218000
http://www.apart4u.co.uk/news/category/questions-and-answers/diagrams/

found that moisture is getting to the timer control and causing mains trip!!!!!! need to dry out timer control then all should be well , aided drying with hairdryer, design flaw will cause this on most is70c i think.

A tumble dryer that isn't heating up at all needs checking with a continuity test meter. The most common cause is a heating element failure, or t.o.c's going open circuit. It depends on which make and model of tumble dryer you have as to how easy it is to get to the relevant parts. Some tumble dryers have heating elements that are easily accessible by removing the back panel, and can be tested for continuity or checked for obvious breakage. Others though have their heating elements inside, which aren't accessible without stripping the dryer down. Tumble dryer heating elements are always protected by thermal fuses which are usually simple devices with 2 wires connected. They can be tested for continuity with a test meter
or
If power is getting to the tumble dryer and the socket is definitely OK, then the most common problem with tumble dryers not working is when the door micro switch fails, or the catch on the door that operates the switch either breaks or no longer activates the door switch. Check for broken door catches. There is usually a plastic peg on the door that pushes through a hole in the tumble dryer's casing where the door catch is. Closing the door should operate a simple micro switch. If the plastic peg is broken or bent it might not operate the switch properly

Check for a tripped circuit breaker (a ganged double breaker), sometimes only one breaker trips without tripping the other. Switch breakers off and then back on. If you have access to a voltmeter, check for 220 volts AC at the the two slanted slots in the dryer socket. Occasionally, one breaker of the pair will fail internally--replace the pair. If 220 volts is present, then problem is internal to the dryer. Usually, it is a short circuit in the heating element which causes the circuit breaker trip.

Hi.
Try it with the heater disconnected, you will find it at the rear of the m/c at the bottom left behind a removable panel.
You may have to remove the top cover and the right hand side panel looking at the m/c from the front. Try it again.
I fit does not trip. then your heater is faulty.
If it still trips then you are probably going to have to call en engineer

If your dryer is tripping the main breaker in your swich box, then it probably has some sort of fault, however It could be overheating due to the lint filter being clogged or perhaps if you have it ducted to outside, the duct is blocked.

If these things are not the cause then you probably need a repairman