Random earth leakage problem

[garthu]

You gonna have your hands full with this one...I'm not a pro on this so leave it to the likes of AndyD/Dave etc but wanted to chuck this in anyway as have had a load with it with the rains. Related to water anyway? Rain, sprinklers, bath emptied. Sure you considered it but just offering.

AndyD... love the comment..

Not sure what 'blow the fault clear' means but the phrase is exciting in a very scary sort of way.

It does hey! Need to be around to see this one... kinda like an exciting Guy Fawkes eve

[Sparks]

You bet it can be scary. Too many youngsters here for me to suggest it but now the cat is out the bag. I just hope they are at least carefull when trying it. I have read this thread from the beginning and it appears all the bases have been covered. In light of the fact that the power tripped with the 'scope I suspect it could be a "imported" multiplug. The finest quality I love as much as a bicycle pedal. I am however also considering the scope itself does it perhaps have a transformer and then finally, is there perhaps a incorrectly installed SPD? As for CBI, they are all I use.
As was mentioned, the best for you here is to note what is plugged in at the time of tripping.
In closing, do not throw the geyser out before checking. Some idiots actually do wire them through the ELCB

[Dave A]

AndyD... love the comment..

Not sure what 'blow the fault clear' means but the phrase is exciting in a very scary sort of way.

It does hey! Need to be around to see this one... kinda like an exciting Guy Fawkes eve

Probably sounds more dramatic than it is - certainly not Guy Fawkes level. What you're trying to achieve is a fault current limited by the over-current protection rather than the piddling 30 mA or so you get on earth leakage protection. It makes the flash-over point easier to identify (especially in the dark), or permanent (carbon tracked or fused).

We normally go this way when we've identified an underground cable fault, but the client doesn't want to run to the cost of a thumper test or replacement of the cable without clear, unarguable evidence - and they're not happy with a marginal insulation result using a meggar. Take the cable off earth leakage, put earth leakage protection on the demand end, and with the next rain the fault really blows.

However, we did have one where we'd pinned the problem down to a lighting circuit. It turned out the surfex cabling had a series of tiny pin holes in it - literally only visible with a magnifying glass - and I doubt we would have found exactly what the problem was any other way than watch for the flash.

[BillH]

OK, sparky came back today to connect the new RCD in parallel, but this was a miserable failure as he could not get it right and ended up with everything tripping. We are now back where we started with a new RCD that doesnt do anything?

Anyone know of an electrician who knows what they are doing??

[AndyD]

I've come across those damn 5 into 1 multi-plug adapters where the indicator neons in the switches were wired between the switched live coming off the switch and the earth. Each multiplug showed about 2.5 MΩ @ 500volts test and three of them was enough to cause nuisance tripping.

The thing with earth leakage is that unless the circuits are all on individual RCBO's it's a cumulative fault so a lot of small IR problems dotted around an installation all mount up to appear as one big problem at the single RCD.

[AndyD]

OK, sparky came back today to connect the new RCD in parallel, but this was a miserable failure as he could not get it right and ended up with everything tripping. We are now back where we started with a new RCD that doesnt do anything?

Anyone know of an electrician who knows what they are doing??

I love a good fault that you can get your teeth into but unfortunately I'm flying out again on Monday and won't have time to commit to this type of problem before I go. I'll pop into the forum while I'm away as time permits so if you don't get sorted out in the next 2 weeks you're welcome to send me a pm and I'll schedule a visit when I return.

Good luck.

[BillH]

I love a good fault that you can get your teeth into but unfortunately I'm flying out again on Monday and won't have time to commit to this type of problem before I go. I'll pop into the forum while I'm away as time permits so if you don't get sorted out in the next 2 weeks you're welcome to send me a pm and I'll schedule a visit when I return.

Good luck.

Many thanks for the kind offer! Still feeling a bit shell-shocked after this mornings "re-wiring" of the RCD exercise - in the process with the multiple on/offs I now seem to have two UPS units that don't work anymore!

[BillH]

After three or four sparkies on the same problem, with no progress other than outwardly through my bank account, I am amazed at just how incapable these guys have been at even reasonably logical (scientific) fault finding. This is very worrying as it does not say much for the quality of training. They all tell stories about how many times they have been blown off their ladders (equally worrying) but anything beyond basic wiring up of a new installation appears to be beyond them.

[Dave A]

There's no doubt fault finding is the real test of a sparky's understanding of their trade - and nuisance tripping can be a real hunt for the proverbial needle in a haystack (or a pile of needles as Andy points out).

Struggling to nail down the cause of the problem first time around is kinda understandable and forgivable - being unable to separate that outbuilding circuit and get it off the main house earth leakage unit is less easy to accept.

[murdock]

cbi...heineman...same company...the older earth elage units where the better ones...the new ones...seem to be a lot more "sensitive" to voltage fluctuations etc...or so i am told by the experts...but if the earth leakage is really old and has been causing endless tripping problem...it "could be a place to start...

having 2 earth leakage units in series is just unpracticle...the ony reason you fit one in an outbuilding...so that the person in the outbuilding doesnt have to keep going into the house to reset it...so you isolate the outbuilding from the main house..etc

the older type light fittings like the 8 ft double with the big ballast have caused many a headache for me in the past...especially in factories where we have multiple rows of lights...the newer 5 ft and electronic ballast units dont seem to affect the earth leakage unit as much...but then in saying that i dont connect light fittings to an earth leakage unit...and the fatories which i service...i remove the light circuits from the earth leakage...if they create an issue.

dave the sound of it is bad...but in theory only 15 amp plug sockets and a few other items as per sabs regulations are required to be on earth leakage...maybe they should try an insulation resistance tester "megger" before blowing them selves up... dont ever try that if you work near RBM or any of those big companies in richards bay...the DOL are like lice in that place