Electrics tripping

[m0t]

We have an electric bidet toilet seat in our bathroom. It's connected to an outdoor rated socket in a cupboard under the sink. The socket is fed by 2.5mm t&e that runs to a FCU in the airing cupboard. The FPU is fed from a 10mm cable (originally run for a shower) that connects to its own MCB in the consumer unit.

This morning all the downstairs electrics went off. In the fuse box the MCB for the toilet had flipped and the RCD that protects the downstairs circuits had also flipped.

After turning back on I went round the house and discovered the neon on the toilet FCU was out. I assumed the toilet had failed.

I unplugged the toilet and replaced the fuse in the FCU and restored power to the socket which works.

I took the toilet seat apart and couldn't find any evidence of anything having gone pop so plugged it back in. The seat works perfectly.

I then checked all the connections in the socket and FCU and couldn't find anything lose and there was no evidence of anything having gone wrong.

Obviously something has gone wrong somewhere for it to trip. Can someone provide some advice on things to check? I have a multimeter from my time repairing old cars but have never used it for electrics but could test things with some guidance.

I can't afford to get anyone out for this because we've spent all our money on a wedding but could afford to replace the seat (I've got a load of Amazon vouchers). If it's anything other than that then the other half will have to do without for 6 months.

Thanks

Edit: I originally had my terminology wrong so have corrected.

 

[mwatsonxx]

"electric bidet toilet seat" = middle class problems, get your butler to sort it out.

I'm orf to our outside karsi for a dump, we got an old toothbrush we use for them tangly bits and hangers on.

Bon Soir

 

[ericmark]

I have two RCD's and a RCD tester, and an insulation tester, when first fitted they would randomly trip, and I would test everything to try and find out why, but never did find a fault, as time went on I found we would get batches of trips followed by long time with no trips and nothing to show why we had got the batch of trips, even an electric storm can cause the RCD to trip, all RCD's are not equal some have electronics to try to stop them tripping in error, others will trip with slightest spike. Test them with a proper RCD tester and they both show same results, but in real terms some do trip at the drop of a hat. Unless it happens many times I would not really worry, just reset it.

 

[winston1]

So two RCD type devices tripped. If one was fed by the other that would likely happen, but if they are independently fed, as they should be, dual trips most likely cause by an outside problem such a surge.

 

[m0t]

So two RCD type devices tripped. If one was fed by the other that would likely happen, but if they are independently fed, as they should be, dual trips most likely cause by an outside problem such a surge.

I'm not an expert but both also tripped when the oven went pop. Plus would seem odd that the 13 amp fuse in the FCU would blow and nothing else would.

Is there a reason that the fuse in the FCU would fail but not the one in the devices plug? Both are 13amp.

 

[Cigaro]

Is there a reason that the fuse in the FCU would fail but not the one in the devices plug? Both are 13amp.

Not really. Fuses aren't the most accurate of devices and if there are two in a circuit, even with different ratings, it's a lottery which one will pop first.

It's actually not unheard of (though rare) for a major fault to take out the supplier's main fuse before a fuse/MCB on the consumer unit.

 

[ericmark]

So two RCD type devices tripped. If one was fed by the other that would likely happen, but if they are independently fed, as they should be, dual trips most likely cause by an outside problem such a surge.

Not true, in theory yes, but in practice I know two RCD's one feeding left fuse box and other feeding right fuse box, quite common when one is reset it will trip the other unless all the MCB's which now replace the fuses are opened first, even then if there is a heavy load on a circuit it can take out the other RCD as it is switched on.

OK my RCD's are old, installed in around 1998 but that means I have had them for nearly 20 years, and I know I will get a batch of trips then nothing for 6 months or a year, I will guess spikes on incoming supply, but without an oscilloscope can't really tell, and even with one since it would have tripped supply still may not find out why, it is just something that happens with 30 mA 40 mS RCD's. The old 100 mA S type never seemed to trip, but the 30 mA just one of those things.

 

[Taylortwocities]

In the fuse box the RCD for the toilet had flipped and the RCBO that protects the downstairs circuits had also flipped.

I think that you hmay have your terminology mixed up.
This might help you provide a modified version of your first post?

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

 

[m0t]

I think that you hmay have your terminology mixed up.
This might help you provide a modified version of your first post?

Untitled

• Taylortwocities
• 27 Mar 2010
• 43

Thanks, you're totally right. I should be more careful I've been to the pub

 

[Taylortwocities]

No problem, please can you clarify what items did trip.
\\

 

[m0t]

No problem, please can you clarify what items did trip.
\\

The mcb marked shower and the rcd next to it plus the 13 amp fuse in the connection unit.

 

[Taylortwocities]

Sorry. What's an RCB?

 

[dobby1]

The mcb marked shower and the rcb next to it plus the 13 amp fuse in the connection unit.

Take a pic. There is no such thing as an RCB, unless it's a typo and you mean't an RCD, or an RCBO.

 

[m0t]

It's been a long day...hopefully now edited correctly

 

[m0t]

Right, it happened again