Strange issue with RCD

[PJHassselt]

Hi all,

I have this strange issue. 

Our fish pond has pumps, pumps are connected to the power in what should be a water closed box, but with heavy rain the box is dampy inside. So when heavy rain often the RCD opens. No problem. I understand why this happens. The last few days the RCD also disconnected when there is no rain. Always in the late afternoon, or early evening. I still thought because some damp issues. 

 

When the pumps do not run the whole night, I am afraid my fish will not survive. So then I switched to our solar inverter. Then the RCD stays in (also normal I once learned, no common ground, or something like that)

 

Then in the morning back to the grid, and no problem till the next afternoon/evening.

 

This I all understand. 

But now the strange thing. 

 

I discovered that when the RCD opens, I am unable to close (It opens direct again) Then I power on the inverter, and the RCD stays closed. But.... When I then direct power off the inverter, and go back to the grid, the RCD stays closed (So all works fine) and it stays closed for the whole night. 

 

Like switching on the solar inverter resets something? 

 

Anyone an idea where to look?

 

Kind regards.

[carlyai]

I think you could have leakage current causing the breaker to trip. 

Other people may have a better idea, but I would start by pushing the test button and make sure (maybe) that it's working properly.

Then start turning off switches or power feeds (one at a time) of items fed from the RCB.

You could have leakage current from pumps etc but not up to 30mA, then, with moisture, the total leakage current increases above 30mA and breaker trips.

If you have any power board multiples, try and get rid of these.

I had a similar problem in my aquaponics greenhouse, a power multiple was the problem.

Also my UPS on the WiFi Router caused a RCB trip once.

[Crossy]

It definitely sounds like the damp has gotten somewhere it shouldn't.

 

Check that your boxes are completely dry (Madam's hair-dryer) then try to hunt out any other places where the wet could access.

 

 

[itsari]

37 minutes ago, Crossy said:

It definitely sounds like the damp has gotten somewhere it shouldn't.

 

Check that your boxes are completely dry (Madam's hair-dryer) then try to hunt out any other places where the wet could access.

 

 

I have a distribution box that will not accept the RCD I recently bought . Will not accept even all the distribution breakers are off . 

I am thinking that there is a fault in the bar holding the breakers .

The distribution box is made by  Schneider whom I have tried to ask for advise but without a reply.

Any help would be appreciated ,

I have tried a second RCD that I have and that was the same result .

 

 

 

 

 

Edited December 24, 2023 by itsari

[Crossy]

Hmmm, who installed the RCD?

 

Can you post photos of the board with the lid off please.

 

Are you saying the RCD won't stay on even if all the breakers are off? If that's the case you are probably looking at a neutral to earth fault which can be a nightmare to find.

 

Do check boxes for damp and possible ants.

 

[brianthainess]

1 hour ago, Crossy said:

It definitely sounds like the damp has gotten somewhere it shouldn't.

 

Check that your boxes are completely dry (Madam's hair-dryer) then try to hunt out any other places where the wet could access.

 

 

Or in a bowl of dry rice maybe.

[Crossy]

Just now, brianthainess said:

Or in a bowl of dry rice maybe.

 

Rice may attract the ants we also want to avoid.

[sometimewoodworker]

2 hours ago, itsari said:

I have a distribution box that will not accept the RCD I recently bought . Will not accept even all the distribution breakers are off . 

I am thinking that there is a fault in the bar holding the breakers .

The distribution box is made by  Schneider whom I have tried to ask for advise but without a reply.

Any help would be appreciated ,

I have tried a second RCD that I have and that was the same result .

 

It is very likely that you need an actual electrician who has the tools and knowledge to sort out your system.

[itsari]

2 hours ago, Crossy said:

Hmmm, who installed the RCD?

 

Can you post photos of the board with the lid off please.

 

Are you saying the RCD won't stay on even if all the breakers are off? If that's the case you are probably looking at a neutral to earth fault which can be a nightmare to find.

 

Do check boxes for damp and possible ants.

 

 

[itsari]

Just now, itsari said:

 

Yes, the RCD will not stay on even with all the breakers are in the off position .

I was the one attempting to fit the RCD.

[itsari]

Just now, itsari said:

Yes, the RCD will not stay on even with all the breakers are in the off position .

I was the one attempting to fit the RCD.

The meter is for the house above and not metering the distribution box in the photo .

[Crossy]

Better post a photo of your RCD too please. Close enough that we can read the rating text.

 

If it won't stay on even with all the breakers open you very likely have a Neutral-Earth fault, it could still be the damp.

 

Do you have any test gear (multimeter)?

 

Have you verified that there's no damp in the works anywhere?

 

Please also confirm that it has actually been OK in the past.

 

It is looking like you need a sparks with the proper gear (an insulation tester at least) and the knowledge of how to use it. 

 

EDIT I'm also looking at your main breaker wiring, if the colour-coding is correct (definitely not a given) you appear to have a reversed L&N.

[itsari]

9 minutes ago, Crossy said:

Better post a photo of your RCD too please. Close enough that we can read the rating text.

 

If it won't stay on even with all the breakers open you very likely have a Neutral-Earth fault, it could still be the damp.

 

Do you have any test gear (multimeter)?

 

Have you verified that there's no damp in the works anywhere?

 

Please also confirm that it has actually been OK in the past.

 

It is looking like you need a sparks with the proper gear (an insulation tester at least) and the knowledge of how to use it. 

 

EDIT I'm also looking at your main breaker wiring, if the colour-coding is correct (definitely not a given) you appear to have a reversed L&N.

 

[itsari]

Just now, itsari said:

 

The same RCD is working  as it should in the distribution box in the house fed through the meter you can see in the first photo.

Can you point out which wire is not correct from the photo i sent ?

[Crossy]

1 minute ago, itsari said:

The same RCD is working  as it should in the distribution box in the house fed through the meter you can see in the first photo.

Can you point out which wire is not correct from the photo i sent ?

 

The black and grey feeding the bottom of your main breaker are POTENTIALLY the wrong way round going by colour codes (not really a reliable indication but worth investigating).

 

Do you have a multimeter? Or at least a neon-screwdriver?

 

Please tell me you're not swapping the main breaker for the RCD with the supply live.

[itsari]

16 minutes ago, Crossy said:

Better post a photo of your RCD too please. Close enough that we can read the rating text.

 

If it won't stay on even with all the breakers open you very likely have a Neutral-Earth fault, it could still be the damp.

 

Do you have any test gear (multimeter)?

 

Have you verified that there's no damp in the works anywhere?

 

Please also confirm that it has actually been OK in the past.

 

It is looking like you need a sparks with the proper gear (an insulation tester at least) and the knowledge of how to use it. 

 

EDIT I'm also looking at your main breaker wiring, if the colour-coding is correct (definitely not a given) you appear to have a reversed L&N.

I have sent the wrong photo of the distribution box i am sorry . There has been a change in the supply wiring . I will send to you the correct photo

[itsari]

1 minute ago, Crossy said:

 

The black and grey feeding the bottom of your main breaker are POTENTIALLY the wrong way round going by colour codes (not really a reliable indication but worth investigating).

 

Do you have a multimeter? Or at least a neon-screwdriver?

 

Please tell me you're not swapping the main breaker for the RCD with the supply live.

I have a clamp multi meter and a neon screwdriver

[itsari]

1 minute ago, itsari said:

I have a clamp multi meter and a neon screwdriver

 

[Crossy]

OK, let me get this right.

 

The large MCCB (the white unit at the top) connects to the incoming supply which is split by those two (lethal, please put the covers on) connector blocks one branch of which feeds your distribution board. Correct?

 

The supply polarity now looks correct, please verify with your neon (should light on the brown wire).

 

With the supply off, please check for a resistance between the N bar (all the blue wires) and the E bar (green/yellow wires), you should see a very high resistance / open circuit there.

 

[Crossy]

Ah, maybe I see it.

 

Is that a green/yellow from the bottom of the N bar round to the E bar?

 

With that link there it's not surprising the RCD won't stay on.

 

Do you have an earth rod?

[itsari]

1 minute ago, Crossy said:

OK, let me get this right.

 

The large MCCB (the white unit at the top) connects to the incoming supply which is split by those two (lethal, please put the covers on) connector blocks one branch of which feeds your distribution board. Correct?

 

The supply polarity now looks correct, please verify with your neon (should light on the brown wire).

 

With the supply off, please check for a resistance between the N bar (all the blue wires) and the E bar (green/yellow wires), you should see a very high resistance / open circuit there.

 

The covers are on , they are clear plastic covers .

I have checked the polarity and all is correct

[Crossy]

3 minutes ago, itsari said:

The covers are on , they are clear plastic covers .

I have checked the polarity and all is correct

 

Great.

I get really worried if I can see bare copper, zooming in I can just make out the covers

 

 

[itsari]

Just now, Crossy said:

Ah, maybe I see it.

 

Is that a green/yellow from the bottom of the N bar round to the E bar?

 

With that link there it's not surprising the RCD won't stay on.

 

Do you have an earth rod?

I have an earth rod shared with the distribution box above in the house.

That wire is a bonding from the earth to negative bar.

I had problems installing the RCD before that bonding was installed

[itsari]

Just now, Crossy said:

 

Great.

I get really worried if I can see bare copper, zooming in I can just make out the covers

Its covered for sure . 

[Crossy]

Just now, itsari said:

That wire is a bonding from the earth to negative bar.

 

Well, with that bond the RCD has no chance of remaining on.

 

If you want to implement a MEN system the bond must be between the E bar and the INCOMING neutral (so the blue wire on the main switch).

 

So, for now remove the link so we can see if you still have RCD issues.

[itsari]

1 minute ago, itsari said:

Its covered for sure . 

I think the bar where the breakers are pushed into has a problem but not sure why.

Thinking to buy just the distribution box and remove the existing box 

[itsari]

1 minute ago, Crossy said:

 

Well, with that bond the RCD has no chance of remaining on.

 

If you want to implement a MEN system the bond must be between the E bar and the INCOMING neutral (so the blue wire on the main switch).

 

So, for now remove the link so we can see if you still have RCD issues.

OK , thank you . I will try what you suggest . It makes sense 

It will take a while , i will get back to you . Thanks again

[Crossy]

8 minutes ago, itsari said:

I think the bar where the breakers are pushed into has a problem but not sure why.

Thinking to buy just the distribution box and remove the existing box 

 

Unless something is actually fizzing, I doubt there's an issue there (at least not one that would cause your RCD problems).

 

Step by step, no point throwing money at it until we know what's actually wrong.

[itsari]

22 minutes ago, itsari said:

OK , thank you . I will try what you suggest . It makes sense 

It will take a while , i will get back to you . Thanks again

I have removed the bonding and tried the RCD with a negative result even with all the breakers off.

[itsari]

17 minutes ago, Crossy said:

 

Unless something is actually fizzing, I doubt there's an issue there (at least not one that would cause your RCD problems).

 

Step by step, no point throwing money at it until we know what's actually wrong.

Agree