RCD Tripping on board

[andemz]

Hi all,

My wife was cooking tea earlier she had the electric oven on and the overhead extractor. When she turned the oven off all the sockets in the house went (Up and downstairs are on two separate sockets)

The problem now is that when we try to switch and appliance on it just trips the RCD. It is slightly odd because it doesn't trip when my phone is on or when the wireless is on, both of which are on up and down circuits, but anything else for example the tv, the kettle, microwave or fridge freezer, it trips immediately.

Any thoughts on the problem.

regards

Andemz

 

[Stevoon]

Have you turned the cooker off at its isolation switch?

 

[PrenticeBoyofDerry]

sounds like cooker element.
If you turn cooker on does it work for a while then trip and if you reset rcd immediately, then turn cooker on then trips straight away.

 

[andemz]

No, the cooker is on the other side of the board.

I have called an electrician out and he is going to be coming back again tomorrow to do a full diagnostic on the electrics.

I will post his findings.

 

[ericmark]

Likely you have a neutral - earth fault.

The neutral and earth are bonded to gather before the power comes into the house so they will be the same voltage when there is no load.

However as the load increases the neutral voltage will start to rise towards the line voltage when this reaches the point when between 15 and 30 milliamp flows between neutral and earth the RCD will open.

These faults can be hard to find as simmerstats and the like only switch the line supply and not the neutral. So the main isolator needs turning off which should brake both line and neutral.

Something like a faulty electric kettle can make the RCD trip even when not switched on. So switch off all isolators including things like the immersion heater fuse connection unit (FCU) and unplug all plugs. Then try with a know good high powered item and see if fault has cleared.

 

[bernardgreen]

The Neutral to Earth fault may be on any circuit connected to the CU .

Turning off the MCB ( fuse) for that circuit during fault finding will not have any effect as the Earth and Neutral to the circuit will still be connected. Some "electricians" seem to be aware of that.

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

 

[JohnW2]

The Neutral to Earth fault may be on any circuit connected to the CU .

Indeed so. However, if the OP meant that the initial trip occurred 'instantly' when the oven switch was operated, then that becomes a major suspect. To confirm/eliminate that, as has been said, the OP needs to properly isolate (L&N) the oven (unplug it, if it has a plug, otherwise switch off using the {hopefully present, and double pole} isolator switch close toi the oven - as you say, not by switching off the MCB) - and then see if the problem with the socket circuits persists.

Kind Regards, John