Coffee machine tripping RCD - any ideas?

Coffee machine tripping RCD - any ideas?

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Prawo Jazdy

Original Poster:

4,947 posts

214 months

Wednesday 24th October 2018
quotequote all
Hello,

I’ve had a Delonghi EC152 (basic espresso pump machine) for about 7-8 years. It has been used most days for that time, without any problems. A couple of days ago I plugged it in, and when I turned the switch at the socket on (with the machine set to ‘O’), the main circuit breaker tripped off. This happened again when I reset the CB.

I tried toasters and kettles in the same socket without issue. I moved the coffee machine to a different socket. This allowed me to turn on the socket switch without a problem, but turning the machine to ‘I’ tripped the CB again. I swapped fuses and had no joy. I’ve taken the boiler and innards out of the housing to poke around, and can’t see any damage or anything that looks like it has been sitting in water, or burning or anything.

Does anyone have any ideas for why it has suddenly stopped playing, and how I could test it other than what I’ve already done? I can take it to a repair shop, but they’ll spend up to £65 repairing it before they ask my permission, and it isn’t worth that spend. I’m handy enough to replace parts, but I’ve no idea how to work out what isn’t working or why. I have a basic multimeter if that’s any use for testing it.

Thanks for any suggestions. My late grandfather (an electrician) would not be impressed frown

Edited by Prawo Jazdy on Wednesday 24th October 14:25

thebraketester

14,227 posts

138 months

Wednesday 24th October 2018
quotequote all
Could be a dodgy earth in the unit

frisbee

4,979 posts

110 months

Wednesday 24th October 2018
quotequote all
An RCD trips when there is a small current difference between the two conductors. Could try measuring resistance between live to earth and neutral to earth? I'm guessing the element has failed though.

Prawo Jazdy

Original Poster:

4,947 posts

214 months

Wednesday 24th October 2018
quotequote all
Thanks for that both. I pulled out my multimeter to have a look... and discovered the battery had burst and was dead irked

At least I’ve found out that I’m not addicted to the stuff.

Prawo Jazdy

Original Poster:

4,947 posts

214 months

Thursday 25th October 2018
quotequote all
With a new battery in the meter, I measured off-scale resistance between all the plug pins. Earth pin to the boiler casing had good continuity. Resistance between the element contacts was 50 ohms, and between each element contact and the casing was off-scale. I don’t know if that helps me, but it seems normal to me.

Outbound

337 posts

183 months

Thursday 25th October 2018
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If it is tripping the RCD when in the off position, it is likely the cable/power switch.
Check where the cable goes into the machine through a gland as this is a common point for appliances to fail due to wear.

If it trips out when power switch on the appliance is turned on, then check (I don't know how complex this unit is but it should still have a over temperature stat) over temp stat for continuity through it and to earth.
It may still be the element to be fair, as unless you do a insulation resistance test on it with a Megger you won't know if it is leaking to earth at mains voltage as opposed to the 9V that a multimeter will likely have in it.

Hope this helps.