[Question] Earth Leakage problem has experts stumped

[Alistair Jones]

Every time it rains the Earth Leakage trips on the DB in the house with no other circuit breakers being tripped. The strange thing is, if I immediately reset the Earth Leakage (by juggling with levers and lifting the handle up), everything is fine and the system works perfectly, even though it is still raining. Very strange, it trips at the onset of the slightest rain but then is quite happy to behave itself once the Earth Leakage lever is pushed up again. This is what seems to have stumped 2 electricians that I have called in to look at the problem. Through a long process, I have established that if I disengage the "Outbuilding" circuit breaker (by pushing it down), when it is dry and before the onset of rain, when it does start raining, I don't have a problem and the Earth Leakage does not trip.

Could this just be a faulty or overly sensitive Earth Leakage?

I would appreciate help in this matter.

[tec0]

do you have any lights plugs or anything like that outside... If you do give them a once over with some heavy duty silicone sealant, inspect your water heater see if your copper piping is earthed properly stuff like that. The clue is in the rain itself obviously something is getting wet when it wants to remain dry...

Isolate all your plugs at the DB and unscrew the plugs plate cover see if there is any water accumulating check that all the wires are properly connected... chances are you will find something that is getting wet.

[greasemonkey]

Had something similiar a while ago - turned out to be cobwebs in a pool db. I'm guessing the cobwebs "caught" moisture , created a short/leakage and tripped the earth leakage.Cleaned it out and problem solved

[tec0]

Had something similiar a while ago - turned out to be cobwebs in a pool db. I'm guessing the cobwebs "caught" moisture , created a short/leakage and tripped the earth leakage.Cleaned it out and problem solved

WOW that is actually something to note!!!

[Alistair Jones]

Thank you for the replies. Do you think that I should replace the Earth Leakage unit? Before this problem that I have detailed in this thread, I had a faulty Earth Leakage unit and called in an electrician to take care of it. He talked me into having him replace it with a German make, one which he had on him but which was second hand. He said that a new one was R5000.00 but he would let me have it for R2000.00. I gave him the go ahead. I rent the house out and the tenant didn't notify me of the problem before it was too late. When I tried to get hold of the electrician, he had disappeared. Now I am wondering whether it is a "too sensitive Earth Leakage" unit because this fault seemed to start after this EL was replaced with this second hand EL unit. Does this all make sense? The circuit that I have identified as being problematic is my "out building" circuit. This feeds my garage, which only has one plug and one interior light on it. What makes this so confusing is that after the initial EL trip (which happens when it starts to rain) once you push the EL lever up, every thing works just fine despite the rain pouring down outside. Seems very strange to me.

[AndyD]

To be honest you need test equipment to prove whether the earth leakage breaker is working properly and you need more test equipment to localise the fault. From what you say it does sound like the garage suply circuit is at least partially at fault, there might be something spurred off that circuit you don't know about such as the gate motor or some security/garden lightng to name but a couple of possibilities.

R5K and even R2K sounds expensive for an earth leakage breaker (even abrand new one) especially if it's a single phase unit without overload protection. Maybe you can attach a couple of photos of the DB and earth leakage breaker. I can't believe you're considering replacing it without getting it ramp tested by an electrician. Depending on the fault there's a good chance a decent electrician will find the fault and test and replace the earth leakage if necessary in an hour or two, this would work out cheaper than replacing the earth leakage and finding it's not at fault afterall.

[gobbleteller]

R5K and even R2K sounds expensive for an earth leakage breaker (even abrand new one) especially if it's a single phase unit without overload protection. Maybe you can attach a couple of photos of the DB and earth leakage breaker. I can't believe you're considering replacing it without getting it ramp tested by an electrician. Depending on the fault there's a good chance a decent electrician will find the fault and test and replace the earth leakage if necessary in an hour or two, this would work out cheaper than replacing the earth leakage and finding it's not at fault afterall.

I have to agree with AndyD with this one... just like some mechanics rip unsuspecting people off, so too do so unscupulous electricians. I had an issue the other day with an elr and when I tested its sensitivity, it was tripping at 5mA. Have a look at http://www.livecopper.co.za/categori...FWfLtAodekwAZQ for some pricing if you really want to replace it.

[tec0]

I saw some strange crap when I used to work as a contractor “installing windows” anyhow... I have seen people splicing wiring with what I call speaker wire... The 3 core goes up into the small white pipe but behind it is 2 core speaker cable.

I phoned the owner and asked him to meet me at his place. I tripped the main switch and opened one of the plugs. At first he was upset when I started pulling the wire out but then he saw what I knew was happening.

The 3 core was spliced in the middle with 2 core speaker cable. So yes it looks just dandy when you open the plug the earth is connected everything but it doesn’t work! I don’t know how they got past the inspections because by any standard they should have picked it up.

So in my opinion have the tests done. Truth is you don’t know what is lurking inside those plastic pipes...

This was in 2001 November I think...

***edit***

I have no clue what happened the next day... My job was done so I had no need to return...

[adrianh]

interesting prices... Hager 110A 240V 30mA 2Pole earth leakage breaker retail R802 from EM

You must remember that earth leakage protection and over current protection are two entirely different protection mechanisms. The normal breakers in the house i.e. the breaker for the plugs protects the circuit from going over current which would cause a fire if not tripped. Lets say you create a dead short by wiring the two prongs of a plug together and you have no current protection then the circuit is simply going to conduct as much current as it can. The whole circuit is going to heat up and the weakest element is going to become so hot that it will melt...causing a fire. Thus, current protection stops this from happening.

The purpose of earth leakage is to detect current flowing to earth which of course would cause you getting shocked. Lets say you have a metal cabinet and there the power wire has a nick which rubs against the enclosure. If the enclosure is no earthed you will get a hell of a shock if you touch the enclosure with your wet feet on the floor but that current flow may not be high enough to trip the over current protection.

So, what does this all mean, it means that there is something somewhere that is causing a bit of current to flow to earth when it rains. The chances of the breaker being faulty is ZERO as far as I am concerned because you get the fault exactly when you are supposed to and at no other time. If it was faulty you would have gotten the fault at odd times. I also think that you can eliminate issues within circuits and devices that have no chance of getting wet. Now for the next thing, if it happens when the lights are on then it could be a problem with an outside light because there is current flowing through the light that may return to earth at the outside light, but if the lights are off and it still happens then it is a problem at a plug. My reasoning is as follows. When light is switched off the power is totally disconnected at the switch which means the there is no power going from the switch to the light therefore there is no power that could leak to earth at the light simply because there is no power at the light. The reason I then say that it is caused by a plug or a device plugged in to a plug is because there is live power at the plug that could short.

Ok, so my advice would be to check your outside lights. There is of course a quick and nasty way to work out which one might be at fault...turn them all on and simply have a go at each of them with a hosepipe. If any one of them trips the earth leakage you found the fault. I would think that even if you find one faulty light check the rest of them because they may have the same problem due to design issues. If this doesn't reveal anything then look at devices that could get wet when it rains, an outside fridge under a lapa or something like. If you have plugs of electrical conduits running outside check them.

My 1st point of call would be swimming pool wiring, second outdoor lighting and third outdoor plugs...

If there is a fault on the pool then it would be the pump or the primary side of the pool light. The pool light has a insulation transformer so it doesn't matter if the secondary side is cooked, it would simply take out its own over current breaker. You can test this theory with you trusty hosepipe. turn the breaker for the pump off and all the breakers for the lights. Now make as if it is raining and see what happens, does it trip, if yes then there is a leak on the wiring before those breakers, maybe there is water getting in the box. If it doesn't trip then turn the pump on, if you now get a trip then there is a fault in the pump motor. If not then do the same with the light breaker.

You see, you can work out what the issue by taking each circuit in turn an doing these simulations in a step wise manner by simulating the circumstance under which the fault occurs... Don't try and test more than one circuit at a time and work your way through each circuit logically....

...and most of all...be very careful and aware of safety when doing the whole "make as if it is raining routine" don't go and fiddle with anything while it is wet and live. The fact that nothing happens immediately doesn't mean that nothing could happen...

BE CAREFUL!

[Justloadit]

Adrian,

Current does not have to flow in the live wire for the ELB to trip, if there is a neutral to earth connection, then the ELB will also trip. The manner in which an ELB functions is that the current going through the live must be the same as the the current returning from the neutral, with no more deviation than the markings on the ELB, in other words, if the ELB is market 30mAmp, then the ELB will only trip if there is a differnce greater than 30mA from the current going through the live and returning via the neutral.

[adrianh]

Fair enough, so it means that you an still have a fault in an outside light even though the light is turned off at the wall?

[Justloadit]

Yes, since the switch on the wall simply interrupts the flow in the live wire, the neutral goes directly to the plug or light fitting. There is an earth loop between neutral and live initiated at the supply transformer by connecting a low resistor between neutral and earth. The potential difference between neutral and earth can vary significantly as more loads are connected to the transformer supplying the area.

[AndyD]

Adrian,

Current does not have to flow in the live wire for the ELB to trip, if there is a neutral to earth connection, then the ELB will also trip. The manner in which an ELB functions is that the current going through the live must be the same as the the current returning from the neutral, with no more deviation than the markings on the ELB, in other words, if the ELB is market 30mAmp, then the ELB will only trip if there is a differnce greater than 30mA from the current going through the live and returning via the neutral.

This is what makes finding an earth leakage fault difficult for a house owner. Just switching off a light or socket at the switch or even the circuit breaker in the DB doesn't disconnect the neutral so you can't truely eliminate things by just switching them off. There's one or two exceptions such as a stove where the switch is double pole and switches the live and neutral together but this is the exception and not the rule.

The swimming pool light Adrian mentioned is another exception for a different reason. The isolating transformer that supplies it is a device that the earth leakage breaker can't detect what's happening on the secondary side with regards to low insulation or earth leakage faults. Earth leakage on the secondary side of the transformer is considered inconsequential because of the very low voltage involved.

[Slow Blow]

Take the "outbuilding" circuit off the EL circuit breaker, put a separate sub DB in the outbuilding.
As a rule of thumb, never put pool circuits, outbuildings, sockets and light circuits on the same EL unit, if you do and then get a fault it can take a month of Sundays to find it.

PS, 2K for an EL unit is a blatant rip off

[Pieter00]

Nuisance tripping and earthing

the reason for the nuisance tripping is poor earthing, I recommend you do earth electrode testing and hit some earth electrodes in and connect it up with the supply earth. Stay away from surge protection devices cause electricians are suppose to do a risk assessment if this is to be installed and electricians arent' doing this. Not following this risk assessment procedure will also weaken your earth so stay away. I hit 1 earth electrode with a 16mm earth connected at the meter box at the corner of the house 90 degrees and then another two not more then at a 45 degree angle to almost make contact with the 90 degree rod. this creates a star connection and solved the problem.