Electic Sockets Tripping

[Jag1978]

Hi All – Just a quick question about my Fuse box / electrics.. I believe it’s a Wylex NHRS6604. My Kitchen and my garage extension both run a separate ring and the electrics keep tripping in the whole house not the Lights just the electrical points. The main RCD switch in the middle of the fusebox is what trips not the individual MCB... So cooker. Fridge, microwave washing machine etc.. My main concern is the fridge obviously if it trips randomly during the day it will kill the fridge and the food in it…

The tripping happens very randomly.. Sometimes once in a month sometimes twice a week.. It happened last night and turned it back on at the fuse box. It would stay on for about 2 minutes and then trip off, and this time I was not able to get it to stay on for any more than two minutes. I did the usual check to see if anything was causing the problems. So I unplugged every single device, but still the problem remained. Unfortunately I can’t replicate the issue as it happens so randomly.. Not sure if weather is playing a part as it has happened when it rains but not 100% its due to that just a coincidence that it’s been raining a lot recently. I have outside connections for the lawnmower so I’ve placed a bag over the socket which has been there for the last few months so I know it’s not water getting into the socket..

Before getting an electrician does anyone have an idea of what it could be.. Could the breaker be at fault as it doesn’t actually trip just the RCD.... The only way I can make the system work is to isolate the kitching ring and keeping that off while the rest is switched on that way I’m assumed that the system will not trip.

Help much appreciated

Jag

 

[PrenticeBoyofDerry]

How many circuits are covered by this RCD at the board?
Such as are the outside of house sockets on different MCB to those in house?

 

[Jag1978]

Hi PrenticeBoyofDerry

This is how they are labelled up:

1. Ring Main Sockets Up
2. Ring Main Sockets Down
3. Ring Main Sockets Kitchen
4. Ring Main Boiler & Attic

Number 3 is the problem one and I believe the outside sockets are part it. That Number 3 covers the whole kitchen, downstairs study and Washing machine. Its just that number 3 doesn't ever trip just the RCD. I know number 3 is at fault because I keep that off and everything then functions as should aside from the ring 3 items

I'm tempted to replace the MCB

Many thanks

Jag

 

[PrenticeBoyofDerry]

It is highly unlikely a MCB issue. The RCD is tripping because circuit 3 has an earth leakage issue.
You have said that you have taken off load all plugged in (that means removal of plugs not just switching off at socket) appliances and have you also disconnected any fused spur connected appliances?

If the problem still remains once all loads are completely of circuit, then we need firstly to be looking at the outside socket, as this has a potential for water ingress from the weather. So does this socket have a double pole isolator within the property, such as switched fuse connection, or is it spurred from an internal circuit or fuse board?

 

[Jag1978]

Thanks for your prompt reply.. Yes I disconnected all plugs and removed fuses from all the spurs.

With reference to the outside connection unfortunately it was put in by the previous owner. I myself only moved into the property 4 months ago.. Looking at the fitting Its a double socket switched plug. I opened up the socket to check for water ingress but everything looked fine, no build up of condensation and the plugs seemed to be fine.. I can't comment on how the connection is made to the main ring. There is nothing marked on the fuse box to reference the external sockets.

Thanks again

Regards

Jag

 

[PrenticeBoyofDerry]

Is there another socket close by to the external one, inside the house?

 

[Jag1978]

The outside socket is in the middle of the garden... and my garden is quite long so there isn't anything very close to it...

Jag

 

[PrenticeBoyofDerry]

That's a bugger then! As that would be favourite on my book.

It is now really down to investigative work on the circuit. More than likely electrical testing equipment needed.

 

[Jag1978]

Yeah my thoughts exactly.. I'm thinking will have to now get an electrician in and investigate...

Just hoping that he can see the fault even if everything is working fine..

Jag

 

[PrenticeBoyofDerry]

Investigating a fault like this is often a tricky one. I would be wanting to find the supply feed of outside socket and disconnect, then see if the fault has been eliminated.

 

[Jag1978]

Might be a silly question but are you saying that the outside socket is piggy backed off one of the internal sockets thus finding the socket nearest to the outside one..

I guess just unscrewing the face of it will tell me if it is piggy backed

Thanks

Jag

 

[PrenticeBoyofDerry]

I am suggesting that it is possible that the outside socket is spurred from an internal one, or it could go straight back to the CU. When I install outside sockets, I install them via an internal two pole isolator, so it can be isolated through pole live and neutral.

But in your case it maybe just taken from an internal socket without isolator.

If the outside socket was a spur, then I would be looking for the supply socket, but it would still require some testing to prove you have disconnected the correct conductors

 

[Jag1978]

Thank you kindly for all your help I'll look further into it

Jag

 

[Aragorn84]

If the one RCD covers those 4 circuits, what makes you so sure its the kitchen thats causing it?

I had a similar random issue in our old place and it was dodgy junction boxes under the floor which would get damp when it rained lots as the water table was high enough to "flood" the subfloor area.

 

[Jag1978]

Aragorn84 - Process of elimination every other circuit MCB works fine it seems to only trip the RCD when the kitchen ring main is on, even if the kitchen MCB is the only one...

This is why I was saying could it possibly be a faulty MCB as the individual MCB for the kitchen isn't tripping just the RCD.. I'm not sure..

Regards

Jag