RCD tripping

Mr.Cookie

Mr.Cookie

Mr.Cookie

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Hey folks

Had a job the other day for a dishwasher tripping the RCD it passes all our test so technical are laying blame at customers house electrics, however I don't like not knowing why somethings misbehaving.

Dishwasher plugged into socket on a 32mA RCD will trip the second it's plugged in, I've tested the socket phase ok, earth is 0.43ohms and RCD rolls over at 24mA.
This is where it gets odd (for me anyway) if the dishwasher is plugged into a circuit that's not on the RCD after five to 10 minutes the RCD will trip, dishwasher carries on working as it's still on a live circuit and will run full cycle.
The dishwasher has been replaced 2 times by retailer for same fault, the RCD has been replaced and an electrician has tested the RCD'd circuit.

Anyone got any thoughts?
Simon
 
I've got a problem in that when I cook on the hobs and boiling something like spaghetti or potatoes then it will trip something, I think it's to do with the cooker hood but if I turn that off it still trips for a while. I think it is steam getting somewhere but we are getting the whole kitchen extended / knocked out so I'm not that bothered.

Maybe something similar is happening with steam from your dishwasher?
 
Mr.Cookie said:
Hey folks

Had a job the other day for a dishwasher tripping the RCD it passes all our test so technical are laying blame at customers house electrics, however I don't like not knowing why somethings misbehaving.

Dishwasher plugged into socket on a 32mA RCD will trip the second it's plugged in, I've tested the socket phase ok, earth is 0.43ohms and RCD rolls over at 24mA.
This is where it gets odd (for me anyway) if the dishwasher is plugged into a circuit that's not on the RCD after five to 10 minutes the RCD will trip, dishwasher carries on working as it's still on a live circuit and will run full cycle.
The dishwasher has been replaced 2 times by retailer for same fault, the RCD has been replaced and an electrician has tested the RCD'd circuit.

Anyone got any thoughts?
Simon
Click to expand...

I'd give the full install a test, IR on everything. Could be a Neutral - Earth fault somewhere.

Dishwasher would just be creating that little extra earth leakage to tip it over.

Either way I'd point blame at the installation, and have it tested properly.
 
I'm guessing it must be an earth fault (probably with the socket rather than the machine if several dishwashers have caused the problem). It sounds like the positive and neutral are on a different circuit. But the earth could be common. So an earth fault could trip the RCD on another circuit.

I'd be replacing the wall socket that the dishwasher is plugged into. You could also test it with an extension lead plugged into a different socket on the same circuit and also a completely different circuit.

I'm not an electrician.
 
I would use my earth leakage clamp and plug the dishwasher into my earth leakage extension tester (home made) that is basically a small extension cord with the live/neutral/cpc exposed and test the earth for leakage,

pound to a penny the earth leakage combined with other appliances is too much for the RCD,

solution? test everything on the kitchen for earth leakage, and anything with a motor/heating element that could cause it,

if I didnt find it, then a full IR test would be done across the kitchen circuit, then the whole house.

Electrician by trade.
 
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