RCD tripping

[Peter Woodford]

Guys,

just had a call off a customer who i changed a fuse board for a week ago and has reported that when switching the tumble dryer on each time if trips the rcd. readings on RCD 36.4 x 1 and 14.0 x 5 would you suggest changing the RCD.

cheers

 

[Modernelectric]

No those readings are fine. Maybe the tumble dryer needs replacing if it has a high earth fault leakage.

 

[Des 56]

No
Insulation test the appliance
iif everything else is not tripping it then it may just be doing its intended job

 

[Peter Woodford]

would i do this at 250v test and just connect to the ends of the plug and what result should i expect

 

[xraytek]

would i do this at 250v test and just connect to the ends of the plug

The IEE guidelines suggest 500V with L+N joined together, but for the sake of fault finding it wont hurt to test at 250 especially if it shows something up.

Does the RCD trip every time?

Maybe N+E swapped at the socket, and has only come to light since installing an RCD.

I once installed a load of 30mA RCD's that fed single phase machinery (via 16A sockets) and had a nightmare with nuisance tripping even though machines tested ok.

I swapped all the RCD's for 30mA Hager as they claim to have filters to eliminate unwanted tripping, and the problem was solved.

 

[Peter Woodford]

don't think it trips every time but only install last weekend but tripped once last week and once this week so far by the sound of it only when they use tumble dryer, do you mean test 250v on the piece of equipment

 

[chocolate]

Why would you do an insulation resistance test on an appliance? Surely it would be better to do a Portable Appliance test !!!!

There's no doubt it's the tumble dryer at fault here.

 

[alba]

had same problem not so long ago, turned out to be tumble dryer but was difficult to explain to client that since we had done work there tumble dryer now does not work with new installation

 

[Darkwood]

tumble dryers are prone to earth leakage when old either element or motor and sometimes mains supressor (big capacitor to filter mains), if you have any digital timers controls etc on yhis dryer dont do an insulation test as you may blow the circuit boards.
Disconnect the element then try it, disconnect the supressor if it has one and try it again but if you still have tripping out issues then disconnect the motor and insulation test seperately.
Always replace the back or top before testing as a sealed dryer is sometimes needed for the airflow over elements, dont run without motor connected as elements will overheat and be careful of capacitor/supressor as it holds a nasty charge after power is switched off.

 

[chubsy]

Just joined the forum tonight so I hope this is the correct way to post.

I had a fault similar to this. The problem was the appliance and it was down to dampness within the tumble dryer. The tumble dryer was a condensing type and a member of the household had failed to empty the water tank which had at some time overflowed into the back of the dryer. The dryer would start OK but when the heating element was switched in to circuit the RCD would trip.
The problem was cleared by using a hairdryer to dry off the sensors in the back of the dryer. If I remember correctly it was a LG Tumble Dryer.
I would suggest the fault has been there before you changed out the fuse box and the RCD has correctly highlited a earth- neutral fault when the appliance is running. It possibly is faulty only when the timer switches in the heating element circuit.