# Interest group forums > Electrical Contracting Industry Forum >  How to isolate an earth leakage problem

## ians

Step 1 : switch off the main switch, earth leakage unit and all the circuit breakers, unplug everything and switch off isolators (stoves, pool, geyser, etc)

Step 2 : switch on the earth leakage unit first then switch on the main switch, if the earth leakage trips chances are you have a neutral fault, you need to call an electrician. If the earth leakage unit stays up/on go to step 3

Step 3 : Switch on one circuit breaker at a time and wait a second or 2 as you switch them on, if the earth leakage trips as you switch on a circuit breaker, leave the circuit breaker down/off and move to the next circuit breaker, if the rest of the circuit breakers are reset without tripping the earth leakage unit then you have identified the circuit then you can start plugging appliance back in and switching on isolators, you will find some appliance don't work, you will need to get an electrician to trace the fault. If all the circuit breakers reset without tripping the earth leakage unit, then go to step 4

Step 4 : Start plugging in appliances and switch on isolators one at a time until the cable/ appliance trips the earth leakage, unplug the appliance which trips the earth leakage and leave it unplugged, you have identified the problem, you don't need to call an electrician, just replace the appliance, if you switch on the pool isolator and it trips the earth leakage you know it is the pool causing the problem.

*Note!!!!*
This is a very basic explanation of what might be causing the earth leakage unit trip and if in doubt call your local electrician.
Finding an "electrician" capable of tracing faults could be just as tricky as the fault itself  :Wink:

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Dave A (30-May-13)

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## Dave A

We get many calls where "the earth leakage unit won't reset". In trying to talk a client through identifying the problem, we also cover this issue:

With some earth leakage units, resetting a tripped earth leakage unit is as simple as flicking up the switch.

However, with some earth leakage units, you must first *flip the switch down completely* before flipping the switch back up.

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## Sparks

Eish, you got no idea how many times I rode out to a site because they did not listen when I explained that over the phone :Banghead:

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## Leecatt

> Eish, you got no idea how many times I rode out to a site because they did not listen when I explained that over the phone


Easy money... :Cool:

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## Leecatt

> Step 1 : switch off the main switch, earth leakage unit and all the circuit breakers, unplug everything and switch off isolators (stoves, pool, geyser, etc)
> 
> Step 2 : switch on the earth leakage unit first then switch on the main switch, if the earth leakage trips chances are you have a neutral fault, you need to call an electrician. If the earth leakage unit stays up/on go to step 3
> 
> Step 3 : Switch on one circuit breaker at a time and wait a second or 2 as you switch them on, if the earth leakage trips as you switch on a circuit breaker, leave the circuit breaker down/off and move to the next circuit breaker, if the rest of the circuit breakers are reset without tripping the earth leakage unit then you have identified the circuit then you can start plugging appliance back in and switching on isolators, you will find some appliance don't work, you will need to get an electrician to trace the fault. If all the circuit breakers reset without tripping the earth leakage unit, then go to step 4
> 
> Step 4 : Start plugging in appliances and switch on isolators one at a time until the cable/ appliance trips the earth leakage, unplug the appliance which trips the earth leakage and leave it unplugged, you have identified the problem, you don't need to call an electrician, just replace the appliance, if you switch on the pool isolator and it trips the earth leakage you know it is the pool causing the problem.
> 
> *Note!!!!*
> ...


Something I found helpful, as I work alone, is to turn on the TV loud when doing step 4. As you are plugging in the appliances you will hear the TV go of when you plug in the faulty appliance.

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Dave A (19-Jul-13), jkamuz (10-Jan-16)

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## Goobie

A little bit off topic

Do lighting circuits need to be fed through the earth leakage breaker? 

I noticed that all my lighting breakers were fed directly from the mains breaker, thus bypassing the earth leakage breaker. Out of interest I moved it from the mains to the earth leakage breaker to see what happens. There is now one of the lighting circuits that trip the earth leakage. I know which rooms the affected circuit supply power to, but how do I pinpoint the exact light, do I take the bulb out, or disconnect the wiring one room after another until the tripping stops?

Thank you

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## Sparks

If one of those fittings is an outside light, you can start by checking for water ingress. if there are no outside lights on that circuit or they are all watertight, the next most probable cause would be a fluorescent, you would need to disconnect both live and neutral wires from the fitting to eliminate it. After that you can disconnect any ceiling fans. If that does not solve the problem you need to systematically disconnect all the fittings one by one unless work has been done to the circuit in which case you can start there after checking the first three most probable causes.Lights are not required by law to be wired through the earth leakage unit unless there is a ceiling fan on the circuit. that is because all motors must have earth leakage protection as they are prone to earth faults. One drop of water is enough to trip an earth leakage unit.

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adrianh (22-Apr-14)

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## AndyD

To be honest I'd say that when looking for an earth leakage fault there's no substitute for using test equipment. The elimination method can be inaccurate and misleading.

Example if you have a circuit with 2 appliances plugged in. Appliance 1 has 29mA of leakage, Appliance 2 has 3mA of leakage. If both appliances are plugged in together your 30mA eatrh leakage will trip. If either appliance is unplugged the earth leakage breaker should hold. Clearly one of the appliances is faulty but by unplugging things randomly you're not guaranteed to localise the fault.

It's worth remembering the earth on a circuit is dual purpose, it's functional as well as protective. Many electronic appliances use the earth to sink surge voltages using surge protectors. These surge protector networks are connected to the earth and the often have an acceptable amount of standing leakage. If you have ten or more PC's plugged in it's possible for the leakage current to exceed 30mA even when there isn't a fault.

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mikilianis (02-May-14)

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## fundi

> To be honest I'd say that when looking for an earth leakage fault there's no substitute for using test equipment. The elimination method can be inaccurate and misleading.
> 
> Example if you have a circuit with 2 appliances plugged in. Appliance 1 has 29mA of leakage, Appliance 2 has 3mA of leakage. If both appliances are plugged in together your 30mA eatrh leakage will trip. If either appliance is unplugged the earth leakage breaker should hold. Clearly one of the appliances is faulty but by unplugging things randomly you're not guaranteed to localise the fault.
> 
> It's worth remembering the earth on a circuit is dual purpose, it's functional as well as protective. Many electronic appliances use the earth to sink surge voltages using surge protectors. These surge protector networks are connected to the earth and the often have an acceptable amount of standing leakage. If you have ten or more PC's plugged in it's possible for the leakage current to exceed 30mA even when there isn't a fault.


I have had an earth leakage problem for years, it trips for no apparent reason randomly, there is no fixed pattern.
At night with every one asleep, or in the daytime, winter or summer, makes no difference.
A month can pass without any tripping, then all of a sudden four or five times in one day.
I have found that fluorescent tubes seems a culprit, sometimes when I hit a light switch not full on (like not fast enough so that it makes an arching sound, hope u understand what I mean!) it will trip the EL. Another thing, I have an old house, like built in 1967. The DB board looks like a crow's nest, I doubt it will pass the test if I sell in future.
I have found that in recent years, during hot summer days, a greenish sticky substance is coming out of some of the light switches. I also added 400 W outside sodium tube flood lights and I think all my 10Amp light circuit breakers might be too small? All my plug circuit breakers are 30Amp
I also have next to my DB board, one of those devices (DECABIT) connected to the local municipality that I suspect regulates my usage during certain periods, I am not sure?   
I have an electrician friend and he said it can be a nightmare isolating the problem. Any comments or suggestions?

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## Leecatt

> I have had an earth leakage problem for years, it trips for no apparent reason randomly, there is no fixed pattern.
> At night with every one asleep, or in the daytime, winter or summer, makes no difference.
> A month can pass without any tripping, then all of a sudden four or five times in one day.
> I have found that fluorescent tubes seems a culprit, sometimes when I hit a light switch not full on (like not fast enough so that it makes an arching sound, hope u understand what I mean!) it will trip the EL. Another thing, I have an old house, like built in 1967. The DB board looks like a crow's nest, I doubt it will pass the test if I sell in future.
> I have found that in recent years, during hot summer days, a greenish sticky substance is coming out of some of the light switches. I also added 400 W outside sodium tube flood lights and I think all my 10Amp light circuit breakers might be too small? All my plug circuit breakers are 30Amp
> I also have next to my DB board, one of those devices (DECABIT) connected to the local municipality that I suspect regulates my usage during certain periods, I am not sure?   
> I have an electrician friend and he said it can be a nightmare isolating the problem. Any comments or suggestions?


I am going to swallow my pride and answer this one.
I am a highly qualified electrician. However........
I had the exact same problem in my kitchen light switch for years, and I mean about 5 years, you know the story about the mechanics car?
Well this tripping problem had me stuffed, exactly the same symptoms; wouldn't trip for weeks then almost every time you used the switch, even changing the switch didn't work. It also tripped under different circumstances too.
Then I made a contact with a guy who was selling "industrial type" din rail mount earth leakages and i bought a batch.
They are CHINT, but the originals not the fakes.
So one day I removed the behemoth, 20Ma monster that was mounted upon my board and replaced it with one of these new 30ma types.
Voila! Problem gone!
The earth leakage trips at 27 Ma every time just like its supposed to and hasn't had one false trip in the last 3 years.
Just a thought?

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adrianh (22-Apr-14)

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## AndyD

Don't worry about the Decabit device, it's a ripple relay that allows the supply authority to shed the load of your geyser during peak usage times. Decabit refers to the type of signal that's injected into the high voltage supply at source so it's definately a remotely operated loadshedding relay.

If you have a very old earth leakage unit or even a VOELCB then it's possible it's just nuisance tripping when there an arc. This however is fairly unlikely and the frst step is to do some insulation testing on the installation and the items that are plugged in or otherwise connected. There's little other option than to find yourself an experianced electrician who has the approprate test equipment.

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## Sparks

Fundi, you will save a lot of time and money besides the headache by following the guidelines set out from the beginning of this thread. We are qualified guys with years of experience who are trying to help. As Andy pointed out, an accumulation of faulty items can cause an excessive earth fault. Unplugging everything is a quick way to isolate a circuit with a fault. You will also note that the lighting circuits are not required to have earth leakage protection. If they are supplied through the ELCB you will need to isolate them by removing their neutral supplies one by one should the fault be on a lighting circuit. Switching the live supply off does not isolate the circuit. Your "sticky green substance"  can definitely cause an earth fault big enough to trip the ELCB if it is supplied through it. Old ballasts are know to develop earth faults so they are always suspect. Any light switch, socket outlet switch or circuit breaker which does not "cleanly make and break contact" will fail compliance and needs to be replaced. You run the risk of electric shock until the day you replace those switches, the scary thing is, so does your family.

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## fundi

> Fundi, you will save a lot of time and money besides the headache by following the guidelines set out from the beginning of this thread. We are qualified guys with years of experience who are trying to help. As Andy pointed out, an accumulation of faulty items can cause an excessive earth fault. Unplugging everything is a quick way to isolate a circuit with a fault. You will also note that the lighting circuits are not required to have earth leakage protection. If they are supplied through the ELCB you will need to isolate them by removing their neutral supplies one by one should the fault be on a lighting circuit. Switching the live supply off does not isolate the circuit. Your "sticky green substance"  can definitely cause an earth fault big enough to trip the ELCB if it is supplied through it. Old ballasts are know to develop earth faults so they are always suspect. Any light switch, socket outlet switch or circuit breaker which does not "cleanly make and break contact" will fail compliance and needs to be replaced. You run the risk of electric shock until the day you replace those switches, the scary thing is, so does your family.


Sparks, I posted here exactly because I wanted folks like your help, otherwise I would have sought help elsewhere. So I would like to thank Leecat, AndyB and you for replying to my post. Much appreciated. I will start with the guidelines.

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## Sparks

Fundi, while the guidelines will assist you in saving time and possibly finding the fault, they are by no means all that needs to be done. Unless you are fortunate enough to find the fault using the guidelines, you will need an insulation tester/megohm meter/megger to test the final "dirty" circuit. These are not cheap testers which you can buy at the corner hardware store or hyper. They can also cause electrical shock and be lethal in the wrong hands at the wrong time. Be aware that the ELCB is the only item in the DB board which is designed for the safety of the consumer. All the other breakers are there to protect the installation. It is important that you find the fault and if need be replace the ELCB asap. It is your only watchdog against electrocution.

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## fundi

> Fundi, while the guidelines will assist you in saving time and possibly finding the fault, they are by no means all that needs to be done. Unless you are fortunate enough to find the fault using the guidelines, you will need an insulation tester/megohm meter/megger to test the final "dirty" circuit. These are not cheap testers which you can buy at the corner hardware store or hyper. They can also cause electrical shock and be lethal in the wrong hands at the wrong time. Be aware that the ELCB is the only item in the DB board which is designed for the safety of the consumer. All the other breakers are there to protect the installation. It is important that you find the fault and if need be replace the ELCB asap. It is your only watchdog against electrocution.


points taken, thank you and I will report back on my findings

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## ELECT 1

There is no substitute for experience. 
I have a system that i use for finding an earth leakage fault.
Its very basic, but in most cases i solve the problem.
As in IANS post, which is self explanatory .
Unplug all appliances, turnoff underfloor heating, turn off pool (by their DP isolators)
Most of the time the fault is now cleared. Then i check each appliance out that was disconnected, i megger them out. I also systematically put the pool back on, then the UFH and so on.
Now if all is disconnected and isolated, then its a Neutral. Now i remove each neutral from the bar, and more often than not its the last one that is down to earth. I have already checked the lives and they are ok.
Cut a long story short i trace out and locate the problem eventually.
The other nuisance trip is a fridge, middle of the night it usually happens, this is usually a heater in the fridge getting moisture into it.
Some times i put the fridge on a dedicated circuit. hehee.

What i cant understand, and dont have the knowledge to make a comment is why some times the earth leakage works on a .2ohm when it should trip. Any thing less than 1 Meg ohm should in theory trip. ??

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## AndyD

Any appliance with an IR reading of < 1Mohm (1 million ohms) when tested at 250 volts should be considered suspect and likely to cause problems in the near future. The earth leakage (RCD) will only trip when the total IR of all the circuits connected to it goes below 7333.3 ohms if the supply voltage is 220v.

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## ELECT 1

This is correct, BUT !!! but even some Telkom plug in transformers and surge arestors  have very low IR, some times nothing trips, and all still works, but as you say, these should be disconnected from the system.

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## AndyD

Earth currents from surge arrestors aren't necessarily a fault current. If the telkom item is classII it can be supplied by a dedicated circuit and red socket which is not RCD protected. Also the test voltage used when you insulation test something with internal surge arrestors will have a big effect on the test result, especially on telecoms equipment the surge arrestor clamping voltage can be fairly low.

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ELECT 1 (01-May-14)

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## fundi

> This is correct, BUT !!! but even some Telkom plug in transformers and surge arestors  have very low IR, some times nothing trips, and all still works, but as you say, these should be disconnected from the system.


I know this is off topic, but we experience a lot of power surges in this area, lights dimming and brighter. These surge arrestors/protectors for televisions, are they any good?

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## AndyD

Dimming lights is probably caused by voltage dips during peak load times. This is completely different to surges. Surge arrestors won't help protect against voltage dips I'm afraid.

Most decent electronic items have their own built-in surge protection, if you're living in an area that's notorious for lightning strikes then supplimentary surge protection can't hurt but look at protecting the entire installation by having them installed in your DB rather than just protecting individual appliances with a 'piggy-back' type unit at the plug.

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## fundi

> Step 1 : switch off the main switch, earth leakage unit and all the circuit breakers, unplug everything and switch off isolators (stoves, pool, geyser, etc)
> 
> Step 2 : switch on the earth leakage unit first then switch on the main switch, if the earth leakage trips chances are you have a neutral fault, you need to call an electrician. If the earth leakage unit stays up/on go to step 3
> 
> Step 3 : Switch on one circuit breaker at a time and wait a second or 2 as you switch them on, if the earth leakage trips as you switch on a circuit breaker, leave the circuit breaker down/off and move to the next circuit breaker, if the rest of the circuit breakers are reset without tripping the earth leakage unit then you have identified the circuit then you can start plugging appliance back in and switching on isolators, you will find some appliance don't work, you will need to get an electrician to trace the fault. If all the circuit breakers reset without tripping the earth leakage unit, then go to step 4
> 
> Step 4 : Start plugging in appliances and switch on isolators one at a time until the cable/ appliance trips the earth leakage, unplug the appliance which trips the earth leakage and leave it unplugged, you have identified the problem, you don't need to call an electrician, just replace the appliance, if you switch on the pool isolator and it trips the earth leakage you know it is the pool causing the problem.
> 
> *Note!!!!*
> ...


I have followed the steps above. First time the EL tripped was when I plugged back in the power to my gate motor/lights  
So the potential culprits seems to be my gate motor and/or two lights at my gate which are switched on/off by a light sensor positioned back at the house and wired into the power cable going to the gate.
I left that unplugged and when I reset the EL it stayed up first time  whereas previously I had to do it a few times.

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## fundi

> I have followed the steps above. First time the EL tripped was when I plugged back in the power to my gate motor/lights  
> So the potential culprits seems to be my gate motor and/or two lights at my gate which are switched on/off by a light sensor positioned back at the house and wired into the power cable going to the gate.
> I left that unplugged and when I reset the EL it stayed up first time  whereas previously I had to do it a few times.


sorry forgot to mention the gate plug was the last one to be plugged in as it is in my garage.

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## F.Viljoen

If only the 2 lights at the gate are controlled by the photocell, good. If your gate motor is also controlled by it, that 7aH battery is not going to last long.

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## Sparks

Why have lights @ the gate controlled by a switch @ the back of the house? Mount the switch by the gate. You can get power from the motor, you also have the option of having the gate switching the lights on when it opens, if you do not require the lights to burn all night. This way you will be aware of your gate opening at night by someone other than yourself.

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## fundi

> Why have lights @ the gate controlled by a switch @ the back of the house? Mount the switch by the gate. You can get power from the motor, you also have the option of having the gate switching the lights on when it opens, if you do not require the lights to burn all night. This way you will be aware of your gate opening at night by someone other than yourself.


I said back at the house, not at the back of the house, it's actually positioned at the front of the house, but it's a good idea you have, thank u. I actually would prefer the lights not to be on all night as I have a municipal one right at my entrance.

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## Kevlaz01

I've done as prescribed and I have located one circuit to be suspect, problem is, I have no appliance connected to any of the plugs

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## Sparks

Do you have and extension or multiplug plugged in? Is it a mixed circuit with outside lights on it? Does the circuit go outside? Is there a joint outside? Did you have rain just before it tripped? Was a plug changed recently? These questions will also help identify the fault.

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## Kevlaz01

I have disconnected everything and switched the CB off. Weird thing, after I disconnected the feed to the plugs and reconnected, the breaker tripped once and a after I reset the EL it stayed on until now. So it is working but I'm still baffled as to what caused the EL trip in the first place, but thanx for your input.

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## MullerR

Hi Everyone.  Im new to the Forum. I am also an Electrician, not long in the trade, so Im still learning alot from experienced guys. I sit with a very confusing problem regarding an earth leakage device.  The earth leakage will trip for no apparent reason anytime of the day and when I switch it back on again, it trips instantly. When I switch off the plugs circuits, it switches on again and then I can Switch on again the plug circuits.  The Unit trips when pressing the test button, BUT when I do a test with the ELCB tester, it does not trip. In the kitchen is a ready board, feeding from the main DB with an earth leakage and that one trips when testing with the push button and the ELCB Tester.  In the garage is also an Earth Leakage device which operates 100% correct. So I changed the Earth Leakage in the house with the one in the garage, cause I though maybe the one in the house is faulty, but it still does the same, does not want to trip when testing with ELCB tester and the one in the garage still work 100%. What can the cause be that it does not want to trip when testing with ELCB tester, but it trips randomly for no reason?

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## AndyD

I did make an information thread about earth leakage tripping faults, it was aimed more at DIY'ers but it might be worth a read for ideas. 

What actual tests have you done on the circuits and what were the results ie insulation (megger) tests of the final circuits and Ze (or Zdb) etc. Did you try an actual proper ramp test of the earth leakage? What loads is the earth leakage supplying?

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## MullerR

Hi Andy.

I Read your article about the Earth leakage tripping faults and I think I still have a lot to learn.  The Information is of much help to me. Unfortunately I have not done any tests like the Insulation resistance and ramp test as I did not have my testers with me, We were visiting the people and the only tester I had was my multimeter and ELCB/polarity tester. Thanx for the info on the testers as well, when I did my trade, testers like the Ramp tester and earth leakage clamp tester were not mentioned to us as important to have testers, but thanx to you I will have to buy me.

The house is quite old and there is not much electronics in the house, or shall I Say not more than there were in the past, just the normal, freezers(2), deep freeze, Microwave, TV, Decoder, PC... The installation also is old and the earth leakage feeds all the circuits (Plugs, Lights, Stove and geyser).   I believe I will be visiting again during this month, but the main thing that buggers me is the fact that it dont even want to trip when tested with a ELCB tester, but the RCD in the Kitchen that is in the ready board trips when tested as well as the one in the garage.

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## Dave A

> but the main thing that buggers me is the fact that it dont even want to trip when tested with a ELCB tester


Assuming you've used a plug socket tester which didn't show any faults on the socket outlet, I've heard of loose terminal connections causing this sort of problem.

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## Sparks

Being an old installation there is possibly bad earth continuity in the house, quite probably a floating earth which will still light the lamp of the polarity tester. Also confirm that the socket outlet you are testing actually has ELCB protection. It could be a new circuit added in with the neutral connected to the top of the ELCB.

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## AndyD

L-N reversal through the earth leakage could cause it possibly not to trip if there was no load current through it during testing plus it could make it not trip on the test button. Also I've come across weird intermittent ''not tripping'' issues with RCD's which have the supply and the load side of them wired the wrong way around. 

My favorite one is that in theory a small low insulation fault N-E on one of the circuits being supplied could also cause the test button not to work but the earth leakage unit itself could still be fine. I've yet to come across this in real life but it could certainly cause some headscratching if it ever did occur  :Smile: .

It's all guesswork until you do the usual tests when you next visit.

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## MullerR

Thanx guys.  With my next visit i will be doing some tests and make sure to get behind this problem.

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## ACEsterhuizen

When would a fault before, (upstream) of the E/L device cause the E/L to trip? Meaning there is no fault under the E/L (L & N disconnected at E/L terminals load side). Ramp test clear on E/L 27Ma @40Ms. TN-C-S supply.

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## AndyD

> When would a fault before, (upstream) of the E/L device cause the E/L to trip? Meaning there is no fault under the E/L (L & N disconnected at E/L terminals load side). Ramp test clear on E/L 27Ma @40Ms. TN-C-S supply.


I see you treated yourself to a ramp tester, I'm jealous, I haven't bought any new testers for several months now  :Frown:  . 

How often is it tripping? Is it regular as clockwork or is it random?

It's not one of the old types of RCD as per pic below that has an earth reference wire on it by any chance? If it is there could be a slim chance that an earthing fault on the supply side could present parallel paths that could cause a fault in a neighboring property to cause the RCD to trip.

 

I've only ever once experienced an external problem causing RCD nuisance tripping and it was an RCD that tripped almost every evening when the streetlight outside the house switched on. I can't for the life of me remember what make it was but I replaced the RCD with an identical new one and it also did the same. After another replacement of a different make it stopped happening. I did some power quality monitoring at the supply and couldn't see any evidence of transients that would point to arcing when the streetlight switched on so eventually decided it was a harmonics issue with that particular brand of RCD but I could never prove it.

I've heard hearsay of poor connections/arcing on the council supply side causing RCD's to trip as well so maybe check the Ze and the neutral-earth voltage of the supply.

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ACEsterhuizen (14-Jan-16)

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## ACEsterhuizen

Thanks Andy. New SABS approved Schenker SP E/L with L N only no earth. (tried 2 new ones). Total random intermittent tripping. Ze (external impedance all ok when tested (0.17Ω).

You were spot on. Poor connection & arcing N/E on council supply in street feeding to house. Municipality came out open their street box and the N/E was arcing, burning, loose connection, hanging on a thread. Fixed it, all OK, 8 hrs no tripping.

But why? i don't understand why a fault before the E/L would cause it to trip.


Yes i am
 :Stupid:

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## AndyD

TBH I'm not sure why it would cause an RCD to trip, there's no current imbalance on the load side which is the criteria for tripping. I'd guess it's an anomaly with the internal electronics maybe.

How's the tripping fault, is it still holding?

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## Justloadit

> TBH I'm not sure why it would cause an RCD to trip, there's no current imbalance on the load side which is the criteria for tripping. I'd guess it's an anomaly with the internal electronics maybe.


I think it has to do with reflected current flows in the E/N wires. All circuits connected to the council point on the E/N circuits are connected in parallel to all the different loads, however when there is a break on the council side supply line, as is the case described by ACEsterhuizen, and because of high current flows and inductance in these circuits, a pulse is injected into the neutral line towards the load side. THE RCD , by nature of its design, is to trip when there is an imbalance in the currents in the L and N circuits. When this pulse comes down the line, there is a mismatch between the L and N, and the RCD can not differentiate where the imbalance is coming from, source or load, and the mechanism then trips.

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ACEsterhuizen (25-Jan-16)

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## ACEsterhuizen

Hi Andy yes all is ok now thanks. and thank Justloadit I almost understand that. :Wink:

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## Justloadit

The pulse I am referring to is called EMF. 
Its the shock you get when you touch the coil contacts of a 12V relay, and disconnect the power to the coil, you feel a jolt. What happens is the inductance of the coil, because of the turns, causes a reverse voltage of several magnitudes greater then the supply in the opposite direction of the supply for a short duration of time. This is better seen when a relay contact breaks the current connection in a loaded circuit, and you see the spark across the contact points. This pulse is generated by the decaying magnetic field due to the loss of power, and depending on the current can be several hundreds of volts, in the case of a high voltage electrical system. The pulse in your application is propagated down the line through the ELB and discharges in the load Neutral to the earth of the equipment. The reason there is a flow of electricity is due to a capacitance between any 2 metals, the dielectric could be air, PVC or some other insulator. 

This capacitance effect is noted when running long wires side by side, and one wire is connected to N and the other is through a switch to L. When you place the multi-meter across the open switch wire, you get a reading of 100+ volts. This voltage is flowing between your meter high impedance input, and the capacitance caused by the wire PVC. This is also known as floating voltage.

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ACEsterhuizen (02-Feb-16)

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## LloydJ

I've tried all this but ALL my plug circuits aren't working even though ALL breakers are up. Please help??

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## AndyD

If all your circuit breakers are in the up position and there's no power at your sockets then it's not an earth leakage tripping problem. Possible a poor connection somewhere or even a faulty breaker but either way you'll need to get a sparky in woh has the test equipment to find the problem.

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## Sparks

> I've tried all this but ALL my plug circuits aren't working even though ALL breakers are up. Please help??


It sounds simple, but are you sure the breakers are up? I have often asked a client this and when I get to site I see it has tripped. Especially when the board is high it might appear as though it has not tripped because the lever does not come all the way down. Physically feel whether the breaker is up or half-way down(tripped). If all the plug circuits are dead there is no supply coming through the ELCB or to it.

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