A lot of them use Hagar, but dual RCD still.
bet they have 3 ring circuits too
bet they have 3 ring circuits too
Stopping nuisance RCD trips - hob has 6.7mA leakage, normal?
- Thread starter scott1981
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This is what I have, any ideas how to resolve the issue without massive outlay would be welcome 
![CropperCapture[33].jpg](https://www.diynot.com/diy/attachments/croppercapture-33-jpg.243029/ "CropperCapture[33].jpg")
![CropperCapture[34].jpg](https://www.diynot.com/diy/attachments/croppercapture-34-jpg.243030/ "CropperCapture[34].jpg")
An electrican maybe able to shove the RCD along, and fit an RCBO next to the main switch.
depends whats inside. You could do it with the older flexible wylex models.
depends whats inside. You could do it with the older flexible wylex models.
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Replace the right RCD with a (main switch) isolator then all the MCB's downstream with RCBO's?
£250 materials + labour
£250 materials + labour
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OK guys some strange behaviour last night when I was checking out the RCD trips with various things turned off. If I simply turn off the mains (at the isolator between the CU and meter) and then turn it back on again, the right RCD trips. So I turned off the hob circuit, repeat and it still tripped. Turned off the kitchen sockets circuit as well and ... no trip. Hob back on, no trip. Everything else off apart from the kitchen sockets, still tripped. So it's the kitchen socket circuit causing the problem.
So next I went around and started unplugging or turning off as much as I could on the kitchen circuit. In the end I got a really strange result, with everything else off/unplugged, but with both the boiler and the washing machine still turned on (at the fused switches in the utility room) the RCD would trip, but with one off and one on (ie boiler on, w/m off or vice-versa) it wouldn't trip as often, but still about 50% of the time. With both off it never tripped (I tried about 6 times).
The only conclusion I can come to is that both the boiler and the w/m cause a surge of earth leakage when turned on, either one is sometimes enough to trip the RCD, but both together will almost always trip it. The washing machine is pretty new (less than 1 year), the boiler is the age of the house (3 years), so seems odd to me. Is it possible the RCD is just overly sensitive to initial current surge? Or possibly something weird in the wiring that is causing it? Not quite sure what to look at next.
So next I went around and started unplugging or turning off as much as I could on the kitchen circuit. In the end I got a really strange result, with everything else off/unplugged, but with both the boiler and the washing machine still turned on (at the fused switches in the utility room) the RCD would trip, but with one off and one on (ie boiler on, w/m off or vice-versa) it wouldn't trip as often, but still about 50% of the time. With both off it never tripped (I tried about 6 times).
The only conclusion I can come to is that both the boiler and the w/m cause a surge of earth leakage when turned on, either one is sometimes enough to trip the RCD, but both together will almost always trip it. The washing machine is pretty new (less than 1 year), the boiler is the age of the house (3 years), so seems odd to me. Is it possible the RCD is just overly sensitive to initial current surge? Or possibly something weird in the wiring that is causing it? Not quite sure what to look at next.
Turning off the individual circuit MCBs is inconclusive, as it only disconnects L, the neutrals are all still connected and providing multiple other paths for leakage current.
Ultimately the problem is that there are far too many circuits connected to a single RCD.
Moving one or two circuits to separate RCBOs will probably help.
Slinging that inappropriate consumer unit away and changing to all RCBOs is the proper solution.
Ultimately the problem is that there are far too many circuits connected to a single RCD.
Moving one or two circuits to separate RCBOs will probably help.
Slinging that inappropriate consumer unit away and changing to all RCBOs is the proper solution.
It is an accumulation of several small leakages, adding up to enough to trip the one RCD. The long term fix is to split the circuits onto individual RCD's (RCBO's).
It is wrong to assume that turning an MCB off, will mean that circuit will not affect the leakage and RCD trip - MCB's only isolate the live conductor, there might still be some leakage N to E, enough to trip an RCD.
It is wrong to assume that turning an MCB off, will mean that circuit will not affect the leakage and RCD trip - MCB's only isolate the live conductor, there might still be some leakage N to E, enough to trip an RCD.
Also - a small fault on one ciircuit can cause the RCD to trip when a large load is turned on on another circuit.
Anyway, measuring the earth conductor current is still not the way to do it; you must clamp L & N.
Perhaps, out of interest you could clamp the boiler pipes.
Anyway, measuring the earth conductor current is still not the way to do it; you must clamp L & N.
Perhaps, out of interest you could clamp the boiler pipes.
Another cheaper way is to change the 7 breakers on the right for Wylex rcbos. (Of the same specific B value (current)as the current MCBs). (£20 each? £25?)
6,16,20,32
And if diying it, swap the RCD for a main switch, is probably a safe approach.
6,16,20,32
And if diying it, swap the RCD for a main switch, is probably a safe approach.
What am I missing? Why would anyone want two 'main' switches?
It’s just an easier way for a diyer to swap out components avoiding loose connections or configurations not approved by the manufacture.
if we could see inside, I guess we would have a better idea
if we could see inside, I guess we would have a better idea
What - by doing something no manufacturer has ever recommended?
A better idea of what? How do you think it is connected?
Replacing an RCD for main switch is like for like regarding terminals and wires
i suspect it’s got a balcony bus bar, which may or may not be able to be shifted along. Who knows which wylex. They keep using different bus bars.
obviously the neutral would require moving too
i suspect it’s got a balcony bus bar, which may or may not be able to be shifted along. Who knows which wylex. They keep using different bus bars.
obviously the neutral would require moving too
I wouldn’t think that doing that level of work on a CU is a DIY activity. If nothing less, our OP won’t gave an RCD tester in his wood shed.
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