Random earth leakage trips (And some causes)!

A tripping earth leakage unit can be terribly annoying. The more installations I do, the more I have to deal with tripping earth leakages…

The number one most common reason I find after an Inverter installation, is circuits (Plugs and lights) that was connected before the earth leakage in the original DB, We then split them out to the essential circuit part and when we start commissioning, we run into earth leakage issues and very soon it becomes clear that the original electrician could not find the fault and decided to connect the circuit before the earth leakage to “hide” it and get the system going. For us to be able to then sign off our installation we end up looking for the issues and in one such case it took us a day and a half to find and fix earth faults on 6 circuits in one very big 3 story house.

The second most common reason is Surge arrestor plugs. The electronics in them provides a path from neutral to ground, that lowers the resistance between earth and neutral and that ads a small “ma” reading without a real earth fault. Now use them on the output of an inverter with a NE bonding relay that opens and closes every time the grid falls away or being restored… Its almost certain the El will trip.

Look at one such example I found again this week. I made a little vid for the client, but decided to post it here so that others might see it as well. If you experience similar trips, please be on the lookout for these. (I was trying to remove the audio, but did not succeed)

VID: Earth resistance readings.

Please add your experiences with earth faults here?


interesting post - I think you might have solved another electrical mystery for me.

Firstly I am in the dark when it comes to electrical things and rely on so called “qualified professionals” and unfortunately that opens me up for exploitation, this post is not a dig at the electrical profession - just to highlight the “fly by night” operators.

Just before covid struck, I hired a recomended “qualified” electrician, “specializing” in inverter installations to do the final wiring up of my 3kw MUST inverter with it’s own DB containing CB for the ceiling lights & light current wall plugs.

All I wanted him to do was to remove both ceiling light circuits (10 x 14w LEDS) & 1 light current wall plug circuit (LCD tv / media player / 1 x 14w LED lounge lamp) a total of 3 live wires & their matching neutrals from the main house DB and reroute them to the newly installed inverter DB. I wanted them completely off eskom and that’s where the crap started! he didn’t even do anything himself - his “helper” did all the wiring while he sat on his ass! the only thing he did was mount the MUST 3kw inverter and the inverter DB.

The result was the earth leakage in the new inverter DB would trip every time the inverter switched over to eskom power, I had to reset the EL manually everytime we tested it - kind of defeats the purpose of an automatic switchover feature. I requested he come back fix the problem, but he never returned and I never paid him except for materials up front.

roll on a few months later and growing tired of having to get out of bed late at night to reset the EL after loadshedding, I got another “qualified” electrician to come and fault find the problem - this one was bragging about his skill and knowledge of inverter installations and he knew “exactly” what the problem was?

I had by that time found out through various solar forums that you need a clean direct - no EL power supply to the inverter, so his brief was to run a clean power supply, bypassing the main house DB EL to the inverter AC input and also to install a 2 pole “DC” disconnect for my 24vdc 105amp battery supply cables to the inverter. He showed up with a 16amp AC 2 pole CB from brights? After he pulled a clean power supply through to the inverter AC input the EL problem still existed?!! paid him for materials (except the 16amp AC CB) and never heard from him again.

So what was the chances of hiring another “qualified” professional electrician that can’t fix the problem - third time lucky I thought, this time after carefully explaining to him the problem on the phone and warning him if he can’t find & fix the problem - I’m not paying him a cent! He repeatedly reassured me he will fix it within an hour or no charge.

15min later he was knocking on my door. Very pleasant chap - ex Zimbabwean - fully kitted out with tool belt with all electrical instruments, ironically with both previous electricians I had to lend them extension leads / ladder & torch etc. first thing he did was to remove ALL appliances from wall plugs and he checked every wall plug for polarity, or something like that - all plugs were correct except my bedroom wall plug that seem to have an earth wire problem.

He then inspected the newly installed “clean” power supply to the inverter and showed me why my El problem still existed. Seems the last “qualified” electrician had wired it wrong!!
Once he corrected the wiring - and actually bypassed the main DB EL this time, the inverter worked like charm and is still working perfectly, so much so that I don’t even notice when the power goes off or back on again. He also cleaned up the wiring in the new inverter DB, apparently coiling up excess wire is a no no!?

Then a few weeks back another problem reared it’s ugly head - all of a sudden after many years working perfectly, my washing machine & tumble dryer starts triping the garage EL?

thanks to your post above I think I know the problem now - both machines have one of those ELLIES surge protectors on their individual main power supply. I did this years ago as I lost the MB on the brand new washing machine due to eskom supplying crappy power and a new MB from Defy costs R3500! thank gard for guarantees - I just had to pay for the call out. I have since had a surge protector added to the main house DB so I guess I don’t need the ELLIES anymore.

I will remove them and see if the EL trips again - if they do I’ll replace the EL in the garage DB and see if that solves the problem.

thanks for the post.

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Adding to this.

First electrician, after explaining to him and his helper, when fitting the double pole changeover switches, remove both neutral AND live. The helper did not understand fully.

After 4 attempts to switch on, my then 48v APC UPS lost its charger, uneconomical to repair.

Thank sparks for that APC, as it sacrificed itself for all the finer electronics connected to it like routers, PC’s, TV’s etc. If there was no APC, the losses would have been substantially more.

Second round, Plonkster and I learned that the older Multuplus II inverters were extremely sensitive to Surge arrestor plugs. When Eskom comes back on, 2nd DB’s earth leakage trips.

After removing all of them, although better, less tripping, the problem still persisted.

So found new sparkies who have never installed a Victron grid-tied system, we will do this together, came around to get the system properly commissioned for SSEG registration.

After doing the test as per the forms, turned out the earth from the street was faulty al these years, actually never properly working since the house was built. After installing a new earth spike, costs that were unforeseen, the tripping problem was at final last resolved.

Sofar this thread can be summed up in:
Removed all surge arrestors everywhere.
Problem persists, check each plug / light circuit for Incorrect wiring.
And run the SSEG commissioning tests as per the CoCT form.

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Oh I’ve had this problem twice now.

The first thing to understand is that a small amount of “standing loss” is normal. There is supposed to be a few milliamps going to earth. Some of it is just due to the fact that no insulation is perfect: A couple microamps will find its way to earth even if everything is perfect. And some of it is due to EMI filters and surge arrestors. EMI filters are way worse. The average al-cheapo surge arrestor consists of a triad of MOVs (metal oxide varistors). These things have capacitances in the low picofarrad, and they pass way below 1mA.

But some surge arrestors and EMI filters can pass several milliamps. And especially those with the neon lamps in the plugs that indicates whether everything is fine… those leak a LOT! Cut that crap off and just put on a normal plug!

In my previous house, the trouble was transients. The standing loss itself was not too bad, but it would spike over 20mA for a split second when the inverter was testing its bonding relay. The result is that every time the power comes back after an outage, the RCD trips. Very very frustrating. I fixed it by fitting a transient resistant RCD. Cost me 4k.

In the new house, I had no transient issues. I also learned that the CBI earth leakages are much more resistant to transients than many of its competitors. Nevertheless, I had a standing loss of 13mA.

The rules says that a 30mA RCD MAY trip at 15mA, and MUST trip at 30mA. A good RCD therefore starts to nuisance trip around 15-20mA. At 13mA, it meant any sort of disturbance would push me over.

I bought a new laser printer. As you might expect, that has a SMPS, and therefore some kind of EMI filtering. I had to leave the printer unplugged when not in use to prevent nuisance tripping.

I eventually fixed the problem by splitting my essential circuits across two RCDs. The biggest culprit was in the kitchen. My Siemens coffee maker leaks a whole 3mA.

Here is some video material. I got so fed up that I bought a leakage clamp meter a few years ago. Enjoy the sound of my very Afrikaans voice :slight_smile:


That is just sacrilege, you have to get rid of it right now, throw it out … I’ll come be around tomorrow at 10am and pick it up …

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To quote Lord Farquaad
it’s a sacrifice… I am willing to make


Very useful thread. I’ve had my share of this in the past and it drove me nuts.

I eventually (after months) traced it to a faulty PSU for an old LG monitor that I had, plugged into a particular multiplug. As soon as I threw switched on the screen it tripped. It had gotten progressively worse. After I threw that bastard out all was well.

After Jaco put in my system I had a couple of good months, but at some point the same started happening. At leat at this point the DB was split into essentials and non-essentials and only essentials tripped. Eventually traced it to a faulty, soon-to-go oven element. Replaced it and all was well.

Even a laptop charger does this. Took me weeks to find the problem. The inverter part somehow got stuffed. In any wall socket I plugged it in, earth leakage would trip. Actually stumbled on the problem by accident.

Other then that, never had any such issues but this thread is of great value to search out and destroy potential future issues.

One issue with this is that it is so hard for the average home user to test, since most of them do not have the test equipment. While you can do a lot by trial and error, it is a lot harder when the problem is caused by a cumulative addition of appliances. You may well conclude that the problem is appliance X, but meanwhile appliance X just added the last 2mA on top of appliances A, B, C, etc…

It is stupid how handicapped you can be without the test equipment. Recently I repaired a microwave oven. They show you on youtube how to diagnose it. You measure the heater element of the magnetron, the windings of the transformer, the high voltage fuse, and so on and so forth. But the tricky part is the high voltage diode (quite an ingenuous setup, using a diode to make a voltage doubler circuit). The howtos tell you to use the highest range on your digital multi meter. I can tell you that this doesn’t really work. The best tool for testing the HV diode of a microwave oven is an insulation tester. You cannot properly test it with the low voltage a DMM uses…

(And yes… that turned out to be the issue with mine. It blew the HV fuse because the HV diode had gone faulty, and of course that was the last thing I suspected…).

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At least now I know of someone that can fix microwave oven’s if my 20 year old model ever decides to pop :champagne:

when can I drop off my microwave oven? :grinning_face_with_smiling_eyes:

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Also tried the microwave oven fix last year with YouTube guiding me. All good from checking door sensors and other small stuff until it is diode time yes. My cheapish multimeter was of no use there.

Turned out to be the magnetron (which at least I correctly diagnosed) and a transformer part if memory serves - had to take it in because couldn’t sort it myself.

The saying goes, “If you ain’t got the right tools, don’t start the job” - words I seldom live by lol.

Oh yes, and you need to know how the tools / equipment work.

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There is a point where it is just easier to buy a new one, especially of the old one has a bit of wear and/or rust on it. This is actually precisely what I did. When it stopped working, I went to a local appliance store and bought a new one. The main reason: The kitchen is transitioning from White to Silver. The second reason: We’re furnishing the flats in the backyard to turn them into AirBnBs (yeah yeah I know… COVID… not much else to do with them), and I was going to need another Microwave anyway.

That meant I had all the time in the world to diagnose and learn about how they work. Some of it was fairly easy. The transformer feels warm to the touch, so clearly it gets power and all the switches and stuff are working. So I could skip the entire door switch part and go straight to the next step… :slight_smile:

Also slowly but surely busy with this process. About 1/3rd there. Painfully slow, waiting on utility bill savings…hahahahaha

I did end up buying a new one, but luckily managed to have the broken one economically repaired. Both are silver. :slight_smile:

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At least one thing I know for sure that I beat you on fair and square!


This was an infomative read. Thanks @JacoDeJongh
My recent experience however was a little different. As i recently installed an inverter and split my loads into a essential and non essential load DBs. All of the equipment in my new non essential DB being brand new and the non essential loads moved to be powered from there. Finished the install. Turned the power on and had immediate earth leakage tripping. Turned off all the loads and it would be fine. As this DB powers the high load items in my house, geyser, oven, we checked wiring and tried again. Then issue was still there. So disconnected all loads and wires a spare plug to the DB for testing. And low and behold it would trip with any load, 700w from the grinder, 20w frok an LED globe. It was returned to the supplier the next day. They tested it and deemed it faulty, swapping it out for another new unit. No issues on the “new new” earth leakage.

Yes C.Potgieter, this is where a R180 plug/EL tester is worth the money over and over. When I di COC inspections I find faulty E/L units fairly often.

Had a bit of a panic attack late yesterday afternoon.

As per the picture, I have this blue light in my db showing that the grid is present.

So I walk past this old tablet that is permanently on and showing the VRM portal and I notice the big red horizontal bar stating grid lost… and I off course immediately glance in the direction of the DB to confirm… but wait, the blue light is on!!!

So panic sets in, as this is around 18h00 and the wife is merrily blasting away on the air fryer and microwave etc, as this is her time to do stuff like that. Glance back towards the tablet to see that the batteries is already down to 94% in less than 20 minutes and gooing those amps!

Run around like an afkop hoender trying to find the problem, looking at all three of the db’s in the house and running to the inverter in the garage which is busy inverting and showing there is no grid input but I cant find the problem.

Shout to the wife to switch all appliances of and I get ready to switch us back to Eskom with the changeover switch installed at the critical load db.

Now during this panic (because you know, my batteries got hurt now and my inverter is probably stuffed as well) I at least recall Plonkster stating that it is best to first switch everything off by sommer testing the earth leakage which is also at the changeover switch.

Remember him saying that those Hager breakers was not really designed to change over directly on full load so trip everything rather.

And then it dawned on me. Earth leakage…

So I run back to the main non critical load db and voila! The earth leakage there had tripped. :grinning_face_with_smiling_eyes:

Why I didn’t bother to look there, or even consider it at the time, is because that thing had tripped only once or twice in the entire 6 years we’ve been living in the house. And because you can barely see it against the black background.

Panic is an ugly thing people!


Now if you had the inverter supplied from before the RCD, this sort of thing would not happen. You are allowed to do that, since you are not feeding sockets with it, and the inverter isn’t fitted in a place where kids can get to it (right?). Although in my own home, I have a 300mA RCBO in front of the inverter, so I still get fault protection for gross leakage currents, and it also serves as overcurrent protection at the same time.

RCD? Residual current device is my best guess. What is this? Oh this is the earth leakage?

No the inverter is in the garage which is apart from the house. No kid gets near my garage!