elcb tripping

eurokev · 17-12-2015 11:52pm #1

hi an elcb keeps tripping in the gf's parents house. It stays for differing lengths of time.
I have tried isolating circuits, and plugging things in and out but it just keeps tripping randomly.
It could stay on for an hour and then just suddenly trip for no reason ( nothing else switched on) or just keep tripping every couple of mins.
There has been no changes to the house recently.
Also none of the mcbs themselves trip.
I am thinking of changing the elcb as I can only think it is faulty, I have no other ideas.
Could anyone offer an opinion before I go and buy one.

Risteard81 · 18-12-2015 4:09am

eurokev wrote: »

I am thinking of changing the elcb as I can only think it is faulty

I would suggest that that is the least likely scenario.

It is far more likely to be an intermittent earth fault.

Maybe compressor in fridge etc.

meercat · 18-12-2015 8:14am

Make sure the immersion is turned off.

18-12-2015 12:52pm

eurokev wrote: »

I have tried isolating circuits, and plugging things in and out but it just keeps tripping randomly.

When you say that you have "tried isolating circuits" most likely you mean that you have switched off MCBs for circuits fed from the ELCB. The problem is that this generally means that only the phase conductor (live) is disconnected. The neutral and earth conductors remain in circuit. The ELCB is most likely tripping because a small current is flowing between neutral and earth even when the associated circuit is switched off. For this reason my advice would be to employ the services of an electrician.

Intermittent faults ELCB (generally referred to as "RCDs" nowadays) are always the most difficult to pinpoint. They are frequently caused by ingress of moisture (rarely a faulty ELCB). Not enough moisture, the ELCB remains on, a little more moisture and it trips. Sometimes it hovers around the tipping point (very frustrating). This is why meercat sensibly suggested switching off the immersion. Switching off the immersion at the isolation switch disconnects the live and the neutral (as an immersion is fed from a "double pole switch").

Risteard81 · 18-12-2015 1:24pm

2011 wrote: »

The ELCB is most likely tripping because a small current is flowing between live (sic) and neutral even when the associated circuit is switched off.

I presume you mean between Neutral & Earth?

18-12-2015 1:25pm

Risteard81 wrote: »

I presume you mean between Neutral & Earth?

Yes, good catch will correct it. Thanks.

eurokev · 18-12-2015 5:39pm

Cheers lads, ye are sound, I've just moved in to my 2nd year of an apprenticeship is e and I.

I have to say iv found all your advice very helpful having lurked around the forum for the past while.

Anyway he got an electrician in to look at it today when I was working and the problem appears to be fixed. Not sure what it was but I will have a look and update if I figure it out.

Thanks again guys

maxfresh · 18-12-2015 8:12pm

A handy way to find rcd faults is if you can get hold of a clamp meter that reads low value of milliamps, clamp around live and neutral feeding rcd in fuseboard and switch on one circuit at a time you should see the value rise when you switch on the dodgy circuit, this narrows it down to one circuit to fault find on.

Bruthal · 19-12-2015 7:12pm

maxfresh wrote: »

A handy way to find rcd faults is if you can get hold of a clamp meter that reads low value of milliamps, clamp around live and neutral feeding rcd in fuseboard and switch on one circuit at a time you should see the value rise when you switch on the dodgy circuit, this narrows it down to one circuit to fault find on.

A good idea alright, but not as simple as it seems.

A live to earth fault can be identified directly by the offending MCB.

A neutral to earth fault, which is usually the troublesome type, can cause problems, and imbalances, from circuits which are not the problem one.

But the method is still sound. The directly affected circuit will have a higher imbalance than other circuits, for the same applied load.

maxfresh · 19-12-2015 10:07pm

Bruthal wrote: »

A good idea alright, but not as simple as it seems.

A live to earth fault can be identified directly by the offending MCB.

A neutral to earth fault, which is usually the troublesome type, can cause problems, and imbalances, from circuits which are not the problem one.

But the method is still sound. The directly affected circuit will have a higher imbalance than other circuits, for the same applied load.

True ,if there is a significant earth leakage it can be easy to spot with this method ,an example i had was a dishwasher that flooded because of a blocked waste pipe was quite easy to see the earth leakage rise to 30ma when the dishwasher was on.
These rcd faults can have u really scratching your head and wishing each circuit was on its own rcbo.

eurokev · 20-12-2015 2:12pm

op here

The electrician just put what they thought was the troublesome circuit on to a another mcb.
The electricity tripped again after a few hours. I have no idea why he did that.
Anyway, I changed the elcb for a new rcd and there has been no tripping for the last couple of days, so it appears that that was the problem

Bruthal · 20-12-2015 2:17pm

Rcbo's on all circuits would eliminate a lot of these problems. Eventually it might be the norm.

20-12-2015 2:19pm

eurokev wrote: »

Anyway, I changed the elcb for a new rcd and there has been no tripping for the last couple of days, so it appears that that was the problem

With the proper test equipment it is possible to test an RCD to see if it is too sensitive (or not sensitive enough) and to see that disconnection times are met (as per ET101).
These tests should be carried out on a replacement RCD.

How do you know you have not replaced a working RCD (ELCB) with a faulty one?

20-12-2015 2:20pm

Bruthal wrote: »

Rcbo's on all circuits would eliminate a lot of these problems. Eventually it might be the norm.

+1

Just like the way it is the norm in industrial installations.

Bruthal · 20-12-2015 3:11pm

Interestingly, neutral to earth faults will make RCDs less sensitive to fault currents where the return path is the CPC.

Fir example, a person receiving a shock from phase to the earth of the circuit will require a higher current than the 30ma the RCD would normally trip at.

MikeKaiserBud · 11-02-2019 9:52am

I have a NIBE 1240, over 8 years old now. After being away for a while I found that the elcb in the fusebox had tripped. I pushed the switch back on but it continues to trip as soon as I turn on. I turned the switch to the manual setting and found that the circulation pump is working. The service engineer suggested that going to the manual setting and then back to the normal might kick it into action but I got no joy. The troubleshooter in the manual suggests calling an electrician in the elcb repeatedly trips. Anybody have any experience of this type of problem, or can anybody recommend an electrician in the west (I'm in Sligo) with some knowledge of heat pumps?

11-02-2019 12:38pm

I’d go with the calling the electrician plan if I were you. There is an assumption often made that these units trip because they are faulty when in reality more often than not they are tripping because they should i.e. there is a downstream fault.

MikeKaiserBud · 11-02-2019 8:11pm

Thanks for response. I got talking to an electrician with some experience of NIBE products. His suggestion was to change the circuit breaker from a type B to a type C or D - he thinks they should stop using the B type. So that's the plan for tomorrow. Another electrician wasn't so sure about changing the circuit breaker but I'll see if it works. If it does, I'll contact Unipipe (who supplied the NIBE) to get an opinion from them.

Bruthal · 11-02-2019 8:22pm

MikeKaiserBud wrote: »

Thanks for response. I got talking to an electrician with some experience of NIBE products. His suggestion was to change the circuit breaker from a type B to a type C or D - he thinks they should stop using the B type. So that's the plan for tomorrow. Another electrician wasn't so sure about changing the circuit breaker but I'll see if it works. If it does, I'll contact Unipipe (who supplied the NIBE) to get an opinion from them.

Id suspect they are confusing RCDs and MCBs if it is an RCD tripping, and they are suggesting changing from B to C or D type.

An RCD is the modern (and probably the better description) name for an ELCB.

11-02-2019 8:42pm

^^^ Exactly.

Consider this, the unit worked fine before, what has changed?
Something is faulty, so this fault needs to be identified and resolved.
Swapping a protective device for something different is treating the symptoms, not the underlying issue.

MikeKaiserBud · 14-02-2019 10:10pm

The change from a B32 to C32 solved the problem. I think the term mcb should be used for the part (a trip switch in what we used to call the fuse box) but I'm not sure. By the way, the electrician said that either a sharp rise or a fall in the supply voltage could have caused the tripping of the mcb. Another electrician that I spoke to said that a B rated mcb should not be used with these appliances - should be either a C or D according to him. He has 20 odd years experience of dealing with HPs.

I think I still have a problem however. Although the HP got back into action the hot water and room temps didn't get as high as I expected over a period of two days. Now the room temp had fallen to 11 degrees and there was no hot water - I had been away for a a few weeks and the HP must have been off for at least a week I'd say - so there was a fair bit of heating to be done. I've been going through the various menu items and I found that the Brine in/out temps (menu 5) both read 9 degrees which is about the same as the outside temperature. That sounds strange to me to have the two temps the same. The brine sensor was repalced at the last service in May 2018. Any suggestions?

MikeKaiserBud · 15-02-2019 12:59am

I have a bit more info which bears out what the moderator has remarked on above. I checked through all the menu and found the following numbers;

Menu 5.11 - Hot gas temp 21.1degrees (~ 104 expected)
5.12 - Liquid line temp 21 degrees (~ 48.2)
5.13 - Hot bulb 15.4 degrees (~ 5.0)

Those numbers look like trouble, and there are some other numbers out of the expected range. The current problem does not appear in the alarm log. Compressor not compressing?

15-02-2019 8:06am

MikeKaiserBud wrote: »

The change from a B32 to C32 solved the problem.

I would say that it stopped it from tripping but did nto deal witht h underlying issue.

By the way, the electrician said that either a sharp rise or a fall in the supply voltage could have caused the tripping of the mcb.

First of all if you have a sharp rises or falls in your supply voltage then you have other serious issues. Your supply voltage will vary slightly, but within defined parameters. Outside of these values and you need to get the ESB involved. Secondly this should not cause an MCB to trip, if it does changing the MCB type to resolve the issue is most definitely not the way to go.

Another electrician that I spoke to said that a B rated mcb should not be used with these appliances - should be either a C or D according to him. He has 20 odd years experience of dealing with HPs.

So why did your unit work for 8 years on a B type unless something has changed?

I think I still have a problem however.

Agreed.
You need to get this checked out properly.

MikeKaiserBud · 15-02-2019 10:21pm

Thanks Moderator - I agree with your comments. I'm waiting on a service engineer to come and sort it out.

elcb tripping

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