Kitchen Electrics Tripping Even After Everything Unplugged?

[Gorguruga]

Have isolated on fuse box that the kitchen electrical breaker (which is connected to all kitchen sockets, cooker and boiler) are causing the RCD to trip. Turned off all kitchen sockets and unplugged everything in there. Still tripping when I turn the breaker back on.

There are 3 wall fuses in the kitchen + 1 one wall fuse for the boiler in the cupboard - could these possibly be the culprit? I've turned all their switches off but should I start replacing the fuses and testing them as the next step?

 

[ericmark]

In the main switches on fused connection units are better than removing fuses as they also switch the neutral. First look for something missed like a feed to outside socket or shed. Unplug as much as you can. Switches for hidden sockets like freezer, or washing machine are often single pole so will not remove a earth neutral fault.

 

[stem]

Have you started to use the central heating about the same time as the problem appeared? Pumps and boilers can leak water into their electrical parts and cause tripping. If the heating isolator is single pole, then water between earth and neutral can still trip an RCD even when the isolator is off.

 

[PrenticeBoyofDerry]

It is not uncommon for the boiler to trip the RCD, so if you have unplugged (not switch off at plug) everything on load, you now need to eliminate items that are hard wired to the installation, so anything on a fuse connection or two pole isolator now needs to be turned off, one at a time until the tripping stops. If it still continues after all loads have been removed, then investigation to the hard wiring and accessories attached to this needs to be undertaken.

 

[Gorguruga]

In the main switches on fused connection units are better than removing fuses as they also switch the neutral. First look for something missed like a feed to outside socket or shed. Unplug as much as you can. Switches for hidden sockets like freezer, or washing machine are often single pole so will not remove a earth neutral fault.

There used to be a connection to the shed years ago but it was removed years before I moved in. There are no sockets outside other than the one in the shed which is disconnected with a cut wire protruding out of the socket. But this wire isn't connected to anything, as connection to the fuse box was removed years ago.

 

[Gorguruga]

Have you started to use the central heating about the same time as the problem appeared? Pumps and boilers can leak water into their electrical parts and cause tripping. If the heating isolator is single pole, then water between earth and neutral can still trip an RCD even when the isolator is off.

The central heating was running most of the time for a small bathroom radiator but the boiler was actually repaired last month due to a faulty diverter valve causing a leaking boiler. It hasn't leaked since the repair and the electricity was fine during and after the leak. The bad news is that the fuse box is directly underneath the boiler so could there be some residual water from the leak last month causing the problem? Water did dribble down the back wall and did in fact start trickling on to the fusebox iteself at some points but I kept a close eye on it so the electrics never tripped once while the boiler was actually leaking last month.

 

[Gorguruga]

It is not uncommon for the boiler to trip the RCD, so if you have unplugged (not switch off at plug) everything on load, you now need to eliminate items that are hard wired to the installation, so anything on a fuse connection or two pole isolator now needs to be turned off, one at a time until the tripping stops. If it still continues after all loads have been removed, then investigation to the hard wiring and accessories attached to this needs to be undertaken.

I've turned off the 4 wall fuses at the switches. Should I remove the actual 13A fuses completely from the plastic housing and then test for the RCD trip again?

 

[Gorguruga]

Removed 4 fuses - 3 of them were 13A, the boiler one was 3A. Tried the fusebox again and it still trips.

 

[bernardgreen]

If the fault is a Neutral to Earth fault then switching OFF a single pole switch will not isolate the fault. It can be difficult to locate a Neutral to Earth fault a it can be on a circuit that is switched OFF. This can mis-lead the person looking for the fault

There is a fault on the lighting circuit. Turn OFF the lighting circuit and the RCD trips when the cooker is switched ON. This would suggest the fault is on the cooker circuit and not on the lighting circuit. The RCD trips because some of the current on the Neutral from the cooker divides at the CU and some bypasses the RCD cuasing un-balance and the RCD trips on this un-balance

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

 

[Gorguruga]

If the fault is a Neutral to Earth fault then switching OFF a single pole switch will not isolate the fault. It can be difficult to locate a Neutral to Earth fault a it can be on a circuit that is switched OFF. This can mis-lead the person looking for the fault

There is a fault on the lighting circuit. Turn OFF the lighting circuit and the RCD trips when the cooker is switched ON. This would suggest the fault is on the cooker circuit and not on the lighting circuit. The RCD trips because some of the current on the Neutral from the cooker divides at the CU and some bypasses the RCD cuasing un-balance and the RCD trips on this un-balance

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

Thanks for the information, I think I saw a video about this very issue by John Ward just last night while trying to gather research about my problem:

Not sure what to do next other than call an electrician. I was hoping it would be a simple DIY fix as has happened from time to time in the past but it appears the problem might require an expert. Do you know of anything else I could do to try to isolate the fault?

 

[Taylortwocities]

Do you know of anything else I could do to try to isolate the fault?

It sounds like you have done everything that can be done without some knowledge and an Insulation Resistance tester.

Do go round the house one more time and check you have not forgotten something. It is easy to do.

Let me tell you a personal story:

I recently spent a whole day trying to find why my RCD was tripping - I am undergoing a large refurb of the kitchen at the moment, so I have been doing a LOT of additional wiring.

After a long tiring Saturday trying to plasterboard the kitchen ceiling, I slid into the bath, sipped a cool lager and the electrics tripped. I did everything that I advise on this forum. Unplugged everything on the faulty (ring final circuit), turned off all DP switches. I did it all. Got out my IR tester, split the ring and found an earth - neutral fault on one part of the circuit. It's now 2am, bed time.

Woke up on Sunday. Took down all of my new plasterboard in the kitchen ceiling, tested and checked all of my new cabling. It all checked out.
Started working my way round the ring final, one socket at a time. Still could not find the problem. Was it a screw? Conductor touching a pipe???

Frustrated, just before bedtime on Sunday (and looking forward to another day fault hunting on Monday) I had a shower. Taking my towel from the towel rail I noticed the one thing that I had forgotten about - the electric element in the dual fuel towel rail. I had forgotten all about it, and this is my own house!
The element had failed. I clicked off the FCU, reconnected and tested the ring and it was all working nicely again.

So, it was co-incidence that the element had failed at the same time as work was being carried out. But co-incidence does lead you down a long winding path into the distance.

So check, check and check again.

But it does sound like you need a competent electrician.

 

[Gorguruga]

Great story Taylor, thanks for the advice and good to hear you found out what the problem was in the end. So far, I've only turned off and unplugged all the sockets in the kitchen, since I thought the problem was isolated to the kitchen due the "kitchen sockets" breaker in the fusebox causing the trip. When I try the other breakers individually they all work, it's just the "kitchen sockets" breaker which makes the RCD trip. Do you think other sockets could still be responsible outside of the kitchen?

I live with 3 lodgers and I'm trying to piece together if one of the other housemates had anything to do with it since he was a bit drunk last night and the problem happened after he just came back inside from a rainy garden, leaving a few small pools of water on the kitchen floor (which is nothing unusual of course when it's raining). But, I'm wondering if he somehow got water into the sockets near the kitchen door, or spilled water onto one of the other sockets. He also has a converter plug for his phone and laptop charger, since he has Euro plugs, and I'm sure he had his phone plugged into the converter in a kitchen wall socket at the time too (which again is nothing too unusual). But reason I'm mentioning it is just in case it might be one of the wall sockets causing the trip, if that's at all plausible?

 

[DaveHerns]

Going back to Bernard green's example , how/why does the current on the neutral from the cooker divide at the CU ? I ask because I've just put a new element in my son's cooker to stop the RCD tripping (it has ) but have I not found the real fault?

 

[EFLImpudence]

Going back to Bernard green's example , how/why does the current on the neutral from the cooker divide at the CU ?

Not at the CU.
If there is a neutral to earth fault (very small current from N to E) in a cable (or element) then some current flows to earth rather than back through the RCD.

I ask because I've just put a new element in my son's cooker to stop the RCD tripping (it has ) but have I not found the real fault?

Do you not think that was the real fault?

 

[PrenticeBoyofDerry]

I've turned off the 4 wall fuses at the switches. Should I remove the actual 13A fuses completely from the plastic housing and then test for the RCD trip again?

Removed 4 fuses - 3 of them were 13A, the boiler one was 3A. Tried the fusebox again and it still trips.

Most if not all fuse connection units are double pole, removing the fuse would not make difference providing you have isolated the unit.
If all loads are now disconnected it sounds like a hard wire/accessory issue.
The next step I would take to eliminate/establish where the fault lies, would be to one by one remove the neutral of each circuit that is protected by the tripping RCD, until the RCD no longer trips. This should then flag up the circuit that is causing the issue. It maybe wise to employ an electrically skilled person at this point!