Earth Leakage problem

[J.Spark]

Hi....I am new here and have a question/problem with an earth leakage tripping.

This problem has me stumped and if anyone can help me it would be great.

A client called me out for an earth leakage tripping. Was going to do the normal test to isolate the problem but then noticed that almost all the breakers are making it trip. To cut a long story short I ended up replacing the earth leakage unit and the same thing happens. The strange thing is that this earth leakage trips on breakers which are not even wired through the earth leakage. Also it trips even when there is absolutely no power on the earth leakage.

Any ideas anyone as I am out of options here.

 

[telectrix]

Neutral in wrong terminal block? visual inspection followed by IR testing.

 

[J.Spark]

Hi....this distribution board hasn't been touched in 5years. All wiring and neutrals are where they are supposed to be and has been working with no tripping for 5 years. 11 circuit breakers out of 20 breakers in the board making it trip. Also when the mains is shut off completely as on no power at all on the unit it trips. IR testing doesn't pick up anything.

 

[J.Spark]

I also tightened every connection in the db. Found a few loose connections which seemed to have stopped the tripping for a bit but then tripped again. Thought I was out of the woods. There seems to be a ghost in this db!

 

[Leesparkykent]

Hi....this distribution board hasn't been touched in 5years. All wiring and neutrals are where they are supposed to be and has been working with no tripping for 5 years. 11 circuit breakers out of 20 breakers in the board making it trip. Also when the mains is shut off completely as on no power at all on the unit it trips. IR testing doesn't pick up anything.

Have you carried out IR testing on every circuit?

 

[J.Spark]

Yes I have and it's all good.

 

[micknew]

We had the same problem on a new build, the tripping was caused by a fault on the overhead DNO supply.

 

[J.Spark]

We had the same problem on a new build, the tripping was caused by a fault on the overhead DNO supply.

Hi....was that with no power on the unit as well? The incoming supply is underground here though. But will check that.

 

[Marvo]

Hi....this distribution board hasn't been touched in 5years. All wiring and neutrals are where they are supposed to be and has been working with no tripping for 5 years. 11 circuit breakers out of 20 breakers in the board making it trip. Also when the mains is shut off completely as on no power at all on the unit it trips. IR testing doesn't pick up anything.

Test for crossed or commoned neutrals (and lives) between all final circuits

 

[J.Spark]

Test for crossed or commoned neutrals (and lives) between all final circuits

Will try that as well. Thanks

 

[HandySparks]

Hi....I am new here and have a question/problem with an earth leakage tripping.

This problem has me stumped and if anyone can help me it would be great.

A client called me out for an earth leakage tripping. Was going to do the normal test to isolate the problem but then noticed that almost all the breakers are making it trip. To cut a long story short I ended up replacing the earth leakage unit and the same thing happens. The strange thing is that this earth leakage trips on breakers which are not even wired through the earth leakage. Also it trips even when there is absolutely no power on the earth leakage.

Any ideas anyone as I am out of options here.

Is the thing that's tripping a differential current RCD or an old style Voltage Operated Earth Leakage Circuit Breaker?

Did you test the sensitivity of the first device before you changed it?

What testing have you done?

 

[J.Spark]

It's a voltage operated earth leakage circuit breaker. Trips out at 30ma as well as the new one. Did the manual testing...visual inspection and IR testing

 

[HandySparks]

It's a voltage operated earth leakage circuit breaker. Trips out at 30ma as well as the new one. Did the manual testing...visual inspection and IR testing

Any chance of a photo of this setup?

 

[J.Spark]

Will have to take the pic tomorrow as I have left site already. Bypassed the unit so long and works fine when bypassed. Will send tomorrow. Thanks

 

[Lucien Nunes]

It's a voltage operated earth leakage circuit breaker

This is important and needed to be stated explicity. VOELCBs can trip as a result of a fault in a nearby property even when the ELCB's own installation is switched off, because they monitor the CPC not the L & N. If there is a difference in potential between the earth electrode and any part of the installation CPC, perhaps at a fitting in casual or deliberate contact with an extraneous pipe, then a current will flow through the tripping coil. Possible causes include a non-protected circuit next door dumping current into a service pipe or the rods being too close together and in each others resistance area.

Conversely, this type of problem cannot affect an RCD as it neither knows nor cares what is going on with CPCs and main earthing conductors.

 

[J.Spark]

This is important and needed to be stated explicity. VOELCBs can trip as a result of a fault in a nearby property even when the ELCB's own installation is switched off, because they monitor the CPC not the L & N. If there is a difference in potential between the earth electrode and any part of the installation CPC, perhaps at a fitting in casual or deliberate contact with an extraneous pipe, then a current will flow through the tripping coil. Possible causes include a non-protected circuit next door dumping current into a service pipe or the rods being too close together and in each others resistance area.

Conversely, this type of problem cannot affect an RCD as it neither knows nor cares what is going on with CPCs and main earthing conductors.

Ok....never came across a problem like this....came across many trippings but not one of this nature. [emoji16]

 

[Octopus]

Yes I have and it's all good.

with all the bulbs out and the lights switched "on", including checking the strappers on 2 way lighting?

 

[J.Spark]

No....didn't do that....will double check on that. Thanks for the advice

 

[Octopus]

Have you got a clamp meter?

 

[J.Spark]

Yes I do

 

[Octopus]

Yes I do

what is the "back ground" leakage like across the installation?

 

[J.Spark]

How does one test for back ground leakage?

 

[Lucien Nunes]

Murdoch dunno if you spotted the bit about the ELCB still tripping with the installation off at the main switch? I think that is what was meant (J.Spark, can you confirm?) in which case I don't think it's leakage from this installation but from elsewhere circulating via the MET. This is one of the rare cases where it's actually helpful to clamp either of the earth leads going through the ELCB, normally clamping a CPC can give misleading results but here it's relevant because that's the current in the trip coil. If it's more than the current measured with the two tails clamped together (this system's leakage) then the problem is external.

 

[Marvo]

In the OP he states he replaced the 'earth leakage unit' with a new one, after I read that I wrote off any possibility it was a VOELCB. Photos would be handy if JSpark can attach a couple..

 

[J.Spark]

Murdoch dunno if you spotted the bit about the ELCB still tripping with the installation off at the main switch? I think that is what was meant (J.Spark, can you confirm?) in which case I don't think it's leakage from this installation but from elsewhere circulating via the MET. This is one of the rare cases where it's actually helpful to clamp either of the earth leads going through the ELCB, normally clamping a CPC can give misleading results but here it's relevant because that's the current in the trip coil. If it's more than the current measured with the two tails clamped together (this system's leakage) then the problem is external.

Yes....still trips with the 3 phase main switch shut off. Tested no voltage to the top of the ELCB....which I find very odd. Cannot wrap my head around that.

 

[J.Spark]

In the OP he states he replaced the 'earth leakage unit' with a new one, after I read that I wrote off any possibility it was a VOELCB. Photos would be handy if JSpark can attach a couple..

Will do so when I am on site again

 

[Lucien Nunes]

An N-E fault can trip a TP+N RCD with the three lines isolated (not all 3-phase main switches isolate the neutral, unlike single phase DP). Current e.g. from a TN-S neutral above earth potential can pass to earth at the fault via the RCD N which the RCD will sense as a residual. Hence, the importance of the IR tests even though the fault doesn't require the system energised to trip.

But, what is this thing we're discussing? RCD? VOELCB? I was taking it to be a VOELCB because you said it was, but now I see Marvo has a point.

 

[J.Spark]

OK....let me rather attach some pics of the ELCB and take it from there. Thanks for the help guys. Appreciate this. Will be in contact during the course of the day tomorrow.

 

[J.Spark]

I am from South Africa so the wording may be a little different lol!

 

[Marvo]

I am from South Africa so the wording may be a little different lol!

Ahh, I've got a feeling your terminology is causing kak boet.