My Hotpoint Aquarius washing machine kept tripping the rcd , so I flicked the rcd back on and the machine would work for a few mins then trip out again until finally it would trip out as soon as the machine was switched on, so time for me to investigate I am by no means electrically minded but also not afraid to have a mess with things, after all if the mains plug is out it should be OK, so anyhow I took the top off the machine had a look for loose or frayed wires etc but found nothing amiss from above so put the machine onto its back and took the plastic panel of saw a view of the motor and other stuff could be seen better, and BINGO a wire terminal to the heater element was falling off and had gone all black so I cut the old terminal off and replaced it, at this point I was feeling
and a little smug that I had found the problem and saved a few bob into the bargain, so job done machine back together time to plug her in and switch on, switch on and it trips again 
so square one again machine on its back for inspection No 2 all connections fine had the door switch out looks fine, motor looks fine, no burn smells or carbon deposits about,drum was free to turn, so its ummm time to look on ukwhitegoods for a butchers, I had done all that had been suggested apart from testing stuff because I haven't got the equipment to do it, but there was one LAST simple thing that I could do before I threw the towel in and that was to change the sealed factory 3 pin plug as I had read that they can cause problems so it was cut off and replaced, so this was the last chance for it to work or the washing machine drum was going to get turned into a log burner 
so now is the time to do or die for the machine, here goes switch on and BINGO 
One naughty plug replaced and no tripping of the rcd job sorted.Karl.
