My customer reported that her washing machine repair man said that the protective device in the consumer unit was over sensitive as it kept tripping. I had installed it a few months back, it is a B16 R.C.B.O. It supplies just the single socket for the washing machine, nothing else.
Yes it did trip off after about 5 minutes when the machine was first turned on.
I could only detect a small earth leakage.
My customer said that she had plugged it into a kitchen socket via her extension lead to try that. It tripped off again very quickly, within 5 minutes.
A faulty washing machine I thought.
But no, it turned out to be a thermal overload trip on her extension lead that had tripped off.
I replaced the R.C.B.O. and tried the machine again in the kitchen socket that ran through a 30mA R.C.D. No tripping this time. Unfortunately the R.C.D. was faulty and would not trip off on test button or by my tester.
Then I tried the machine on the new R.C.B.O. It tripped it off in under 5 minutes. Two faulty R.C.B.O.s. NO I thought, that is just too much of a coincidence. A faulty batch?
After a while the machine ran without tripping off anything. I assume that damp got into the heating element and my forcing it to run dried it out. The problem is that when I took the top cover off the machine I could not access the heating element terminals, just E.L.V. circuit board stuff (5V-12V). The main ON/OFF switch is just an E.L.V. circuit board control not a mains switch.
Results. Faulty R.C.D. found and replaced.
Waste water hose leak repaired. But no water inside the machine.
R.C.B.O.s confirmed as being within spec.
Washing machine repair man will be advised of my suspicions about the electrically leaky heating element.
When fault finding check, check and check again to confirm the truth of the matter.
Although others' observations and comments may be useful, take them with a pinch of salt.
Z.
