Intermittent RCD tripping - how to diagnose?
- Thread starter NotSoSmart
- Start date
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Here's the CU:
The label in the bottom left corner says its rated IP2XC
The label in the bottom left corner says its rated IP2XC
The first thing I would reccomend would be doing insulation resistance tests on all cables.
If that fails to find the problem then since you are doing rennovation work anyway I would suggest moving the fridge washing machine and boiler onto a non-rcd circuit (a 20A radial should be plenty sufficiant for the three of them). This will eliminate them as potential culprits and will also stop your fridge warming up when the power does go off.
If that fails then I would inspect any cables and connecitons that you can get to reasonablly easilly.
Splitting the installation accross multiple RCDs would be the next step but doing so may prove costly.
If that fails to find the problem then since you are doing rennovation work anyway I would suggest moving the fridge washing machine and boiler onto a non-rcd circuit (a 20A radial should be plenty sufficiant for the three of them). This will eliminate them as potential culprits and will also stop your fridge warming up when the power does go off.
If that fails then I would inspect any cables and connecitons that you can get to reasonablly easilly.
Splitting the installation accross multiple RCDs would be the next step but doing so may prove costly.
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Apologies, the photo store I was using apparently only works if you're logged in, so it looked fine when I previewed it... 
Now from photobucket:
I'm not sure I have a non-rcd circuit - are you able to tell from the pic, or can you advise me how I can tell?
Now from photobucket:
I'm not sure I have a non-rcd circuit - are you able to tell from the pic, or can you advise me how I can tell?
the two gaps in the middle (where there should be another blank to keep your fingers out) might be RCD or non-RCD circuits. Can't tell without opening the cover.
All the circuits on the right-hand side (with no green line) should be non-RCD.
I can't read the circuit names on either side (picture resolution too low). What are they?
What brand name, part no's etc are on the MCBs and RCD?
All the circuits on the right-hand side (with no green line) should be non-RCD.
I can't read the circuit names on either side (picture resolution too low). What are they?
What brand name, part no's etc are on the MCBs and RCD?
Here are the left and right sides of the cu in more detail, and the cu with the cover off:
There don't seem to be brand names on any of the MCB's or RCD, just the little symbol (black ellipse with red triangle) that you can see in the top left corner of each breaker.
The loose cables you can see used to be connected to the immersion heater. They are still connected to the cu - could this be the cause if they are exposed?
There don't seem to be brand names on any of the MCB's or RCD, just the little symbol (black ellipse with red triangle) that you can see in the top left corner of each breaker.
The loose cables you can see used to be connected to the immersion heater. They are still connected to the cu - could this be the cause if they are exposed?
those bare wires must be removed from the CUAs I feared, you have a budget CU
You appear to have the cooker and an immersion heater on the RCD side. These are both prone to nuisance tripping.
The labels suggest you have two immersion heaters - presumably not?
If you turn off the main switch, it is possible to look under the removable busbar cover at the bottom and see (your busbar will be in two sections) what it does in that gap in the middle.
I am not familiar with this brand, but it looks quite conventional, unless the MCBs are the pronged type.
One thing you can usefully do - trace each circuit cable, and check that, if the Phase (brown or Red) conductor is on the RCD side, the Neutral (blue or black) conductor is in the RCD Neutral block (you have two Neutral blocks). And the non-RCD circuits are in the other Neutral block. A mistake sometimes made is to mix them up. This is one cause of tripping.
From my experience this normally trips RCD as soon as any load is applied.
All redundant ccts should be removed from CU
TBH it's a bit of a mess in the CU and the MCBs on the RCD side look a bit p*ssed that's probably why two blanking plates could be fitted.
If you had an electrician fit this I would get them back to sort it and also apply the correct warning labels as there are mixed colours in there.
JohnD has a picture of what proper install should like.
I've been trying to get the sparks back for weeks, but he is apparently 'very busy'...
OK, if I switch the main switch (the big red one on the right) off, I can remove the individual ccts, yes?
We used to have two immersion heaters (used to be two cottages), but both are now removed and the old ccts can come off.
As this is an old house, it has a number of old style cables with various colour combinations in them. The sparks was using sheathing in the sockets and the light fittings to show the appropriate things...
OK, if I switch the main switch (the big red one on the right) off, I can remove the individual ccts, yes?
We used to have two immersion heaters (used to be two cottages), but both are now removed and the old ccts can come off.
As this is an old house, it has a number of old style cables with various colour combinations in them. The sparks was using sheathing in the sockets and the light fittings to show the appropriate things...
Yeah, if you turn off the main switch, then that'll isolate everything in there with the exception of the top two terminals on the main switch and the two 25mm² supply tails that feed them, then you can disconnect all three conductors on each of the immersion heater cables, clip the exposed copper off and carefully draw them out of the board, leave them nearby just incase they are ever needed for a shower pump, etc, label them as to where the other ends appear though!
EDIT: Switch off the load before isolating it... use the MCBS, and you really ought to prove isolation before touching anything (I suppose in the absense of proper kit, a multimeter would do...just... at a push!!)
EDIT: Switch off the load before isolating it... use the MCBS, and you really ought to prove isolation before touching anything (I suppose in the absense of proper kit, a multimeter would do...just... at a push!!)
Oh, and the make is CGD (control gear direct)
Not sure on the quality, but they ain't one of the big players, the prices are cheap and your breakers look very slanted - a dodgy RCD isn't beyond possibility!
//www.diynot.com/forums/viewtopic.php?t=61983
Not sure on the quality, but they ain't one of the big players, the prices are cheap and your breakers look very slanted
- a dodgy RCD isn't beyond possibility! //www.diynot.com/forums/viewtopic.php?t=61983
OK, the power went off again about an hour ago so I took the opportunity to remove the old Immersion circuit cables. I tightened everything back up afterwards and switched it all back on.
The power tripped again a short while ago.
I guess I'm down to trying to move the fridge, boiler, washing machine and cooker to non-rcd circuits and then n-e testing.
If that gets us nowhere, what cost would I be looking at for replacing the cu with a better model? (what should the sparks have supplied in the first place? This CU was only installed 6 months ago; there were two cottages and so 2 cu's - both quite old and not big enough. the two systems had to be merged)
The power tripped again a short while ago.
I guess I'm down to trying to move the fridge, boiler, washing machine and cooker to non-rcd circuits and then n-e testing.
If that gets us nowhere, what cost would I be looking at for replacing the cu with a better model? (what should the sparks have supplied in the first place? This CU was only installed 6 months ago; there were two cottages and so 2 cu's - both quite old and not big enough. the two systems had to be merged)
Hi again guys - -I'm still having trouble with the electrics. I am ordering a replacement RCCB just so that I can eliminate that from the equation, and noticed another product on the same website:
http://www.allaboutelectrics.co.uk/doc/12/vid/2781/RCD_PROTECTED_SOCKET__-_PLASTIC.html
Can I replace the existing standard double sockets for the fridge and boiler with these to help avoid either of those units potentially tripping the CU?
Thanks!
http://www.allaboutelectrics.co.uk/doc/12/vid/2781/RCD_PROTECTED_SOCKET__-_PLASTIC.html
Can I replace the existing standard double sockets for the fridge and boiler with these to help avoid either of those units potentially tripping the CU?
Thanks!
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