Dishwasher tripping RCD

[Superhoop]

Hello!
On Friday the RCD tripped and I narrowed it down to the dishwasher which was about half hour into a cycle at the time. After a couple of hours everything was fine and it worked perfectly without tripping it.
Unfortunately it has happened again this evening, about 10 mins into a cycle. Playing around with the dishwasher, the plug and the RCD I noticed that it trips the RCD as soon as I plug it into the socket, even before the dishwasher is actually turned on.
I am resigned to having to buy a new one but wondered if these were symptoms of something other than a faulty dishwasher.
Any advice welcome.
Thanks
Matt

 

[ChrisElectrical88]

Outside light on a PIR with the early night coming in, been nearly caught by a few of these.

 

[Superhoop]

I don't think so as it was daylight on Friday when it first happened.

 

[Deleted member 105166]

Matt, using an extension lead, are you able to plug it into a different socket that you know to be on a different MCB or fuse in your consumer unit? Or can you try the dishwasher with nothing else on (preferably tomorrow during daylight!)
As Chris is also indicating above, the dishwasher may not be the cause

 

[Superhoop]

I can try it tomorrow with nothing else on switched on, but all the plug sockets in the house are on the same switch that keeps tripping.

 

[Deleted member 105166]

The things to eliminate are, firstly whether it trips the RCD when there is nothing else on, as it is possible with other appliances on, that the total earth leakage is tripping the 30mA RCD and the dishwasher may not be the largest contributor to that.

Then, if you can plug it into a different circuit, (different MCB or fuse, depending on your board) even though that will be connected to the same RCD, you may eliminate the circuit as being problematic.

 

[Deleted member 9648]

Do not buy another dishwasher based on the fact that the RCD has tripped when the dishwasher is on, it may prove an expensive mistake. It is worth asking an experienced electrician to carry out an insulation resistance test on the entire installation as well as the dishwasher to verify the cause because RCD tripping problems can be unrelated to apparent causes. If you have a local electrician it should be a half or perhaps an hours labour charge,

 

[littlespark]

I can try it tomorrow with nothing else on switched on, but all the plug sockets in the house are on the same switch that keeps tripping.

Is there a socket on your cooker switch you can use?

Is there any physical damage to the dishwasher flex, or does it have a removable plug cover rather than a moulded plug? Check the flex is connected properly and there's no loose strands of wire.

The problem could be the socket itself. Test it with something else plugged in as well as testing the dishwasher in an alternative socket.

There could be any number of problems, but it may be that you D/W has come to the end of its life. How old is it?

 

[Superhoop]

The dishwasher is integrated so difficult to see the whole of the cable, but from what I am able to see behind the kickboards its ok. The plug is a moulded type.
Its a double socket with the second socket being used by the sink food waste grinder thing. I have swapped them around and tried one at a time and there doesn't appear to be an issue with the grinder. The dishwasher also trips the RCD when I plug it in to the grinder socket.
The dishwasher is probably >10 years old. We've lived here 5 years and it was here when we moved in and probably put in when the house was built in 2007.

 

[Superhoop]

ps -thanks for all the tips so far!

 

[*-jester-*]

I agree with what most people are saying, it may not be the dishwasher at fault.

But if you suspect it is:
Can you see the heating element in the bottom of the dishwasher? (With the bottom tray removed) can you see any physical damage to this element. Try running your fingers a long it feeling for any lumps or dents etc.

The heating element is the most common component to fail on a dishwasher of this age and if you say it's tripping the RCD as soon as you plug the dishwasher in then it suggests a Neutral / Earth fault.

 

[Wilko]

Hi - if you've a Consumer Unit with 2 RCDs then do try the extension cord to another outlet (as mentioned above) on a circuit on the other RCD. If you still get the same behaviour (and nothing else trips the RCD ... ) it's likely the DW.

 

[davesparks]

Whilst it is possible for it to be something other than the dishwasher it is more than likely that there is a fault in the dishwasher.

I suggest getting an appliance repair person to investigate, a repair may possible.

 

[Superhoop]

I have just 'powered down' the house, switching all the MCB's off except the one the dishwasher is on. Also went round the house and turned off all plug sockets, plus the Central Heating. I'm pretty sure there was nothing drawing any electricity. Then I plugged the DW in and straight away it tripped the RCD.
Does this mean the odds are its the dishwasher?

 

[*-jester-*]

It definitely looks that way although if I'm to be picky, just switching sockets off will not negate a Neutral / Earth fault if the socket is only single pole switched. In this instance you should therefore unplug all devices as you would do when carrying out an insulation resistance test for example.
But yeah, it looks like it's time to get the dishwasher checked out.

 

[Deleted member 9648]

The thing is if you get a decent electrician in they will be able to test both the dishwasher and the rest of the system in a very short time. Then you can base your fix on not just assumptions, however likely it may seem.

 

[Superhoop]

Update on this. Had a new dishwasher installed yesterday and used it twice with no problems so far.
Thanks for all your help on this.

 

[Richard Williams]

Leaky heater element.
N to E
New element £20-00 ish

 

[Richard Williams]

Can i have the old one

 

[Deleted member 26818]

I think I would rather replace the dishwasher than change the element on one that’s 10 years old.