For what purpose? It is not surge protection, it is a device that measures voltage and current and opens a relay when they are out of range. You can see in the manual they also give a “typical installation” that includes a separate surge arrester.
I always put that step dead last on the list. I have since come to the same conclusion: That you really should exhaust the other options first. Nine out of ten times, you either have a real leak, or your standing loss is just too high.
Removing all those surge arrestor plugs and stuff lowers the standing loss. Those red plugs with the three neon lamps inside are by far the worst… they pass several milliamps to ground. Regarding the transformer supplies, I found that it is not the transformer itself that’s the issue. It is that many of these older supplies typically have some kind of surge/noise arrestor in the box too. The surge arrestor is the culprit.
Re MOVS. I actually tested one. They pass picoamps to earth, if they are suitably rated.
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I do have surge protection, before and after the inverter. Was suggested years ago by a Victron repair center after a spate of LS and resultant additional repairs they noticed. Current LS, another influx of repairs, them seeing 300v incoming after the grid comes back on.
So when a Victron repair center suggests to me some more protections based on repairs they are affecting, I listen attentively.
Also have lost 3 screens and a PC in the last few years because of LS, as solar inverters are not protection devices, so I took further notice when our insurer altered the T&Cs for LS damage claims.
Keep the grid woes outside the house as best one can when there is LS.
EDIT: In light of this topic, when the earth leakage problem is sorted, use the exercise to consider additional protections, my suggestion.
Remember an MOV is basically a cap with a special dielectric - you will also see the capacitance in the datasheet. These small ones have about 350pF capacitance, so that is the same as a ~10MΩ resistor at 50Hz. Now the problem is that you might have quite a bit of higher frequency components also present because of SMPSs (with poor filtering) or inverters (also with inadequate filtering) and then the impedance drops significantly - at 20kHz that same MOV has an equivalent resistance of ~23kΩ. (of course the amount of leakage your RCD will detect does depend on the source of the 20kHz, with the inverter on the other side, it actually has a bigger impact, but as it does not have a 0Ω impedance, SMPSs will couple through.)
Another thing to keep in mind, is since you have all these capacitors between live and earth, what happens when you connect or disconnect at any point other than a zero-crossing? Or if there is bounce, like we expect with a relay and worse with loadshedding?
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That is something one forgets of course, and I certainly tend to forget such things. It is interesting that you would mention 20kHz, because guess what frequency the Multi’s PWM (which it uses to shape the sine wave) runs at … 
It might explain why the ET-Blue garage door opener at my previous place had such a propensity for tripping the RCD, unplugging that seemed to significantly reduce the problem… and the only thing that device had in the back was your usual triangle of MOVs. It never made sense to me… still doesn’t really.
In any case, I found that the clamp meter is amazingly effective and accurate (but it is TRMS!) in debugging these issues. The particular one I have has a peak-hold function that scans fast enough to see exactly how high the leakage rose. What is really nice about that is you can truly divide and conquer, disconnect circuits and observe the effect. It adds a lot of speed to the process.
I even did one test where I removed the RCD and replaced it with an isolator, then let the inverter switch over, and I recorded a 40mA peak! And all of that was transient behaviour from the collective fleet of appliances… because the rest of the installation checked out fine. Earth was proper, earth continuity was good, standing loss was acceptable…
I ended up spending around 9k on solving that problem. Half on the clamp meter, half on the RCD. I was really really fed-up by that point, and practically threw money at it!
Ja. One doesn’t feel great when one gets desperate… 
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@Msifem Can you initiate this fault without loadshedding?
If you switch off the mains breaker does the RCD trip??
RCD does not trip when I initiate this with the main switch. I would like to add that I am connected to the grid by a pre- paid meter and I remember when I was asking for quotation for solar, one installer said pre-paid are a problem. He said they cannot handle the the minute power going back to the grid when loadshedding starts. If that is the case, how can this be resolved? My installer does not know what to do anymore as all tests are done and they cannot find problem causing this.
Does it happen the instant there is LS, or does it take a few minutes before it trips?
It happens immediately with loadshedding
Install an ABB or Hagar RCD with anti-nuisance tripping.
Plonkster and I had the exact same using the same inverters yonks ago.
In my case, after I tried what he tried, replacing the RCD too, after having removed all the surge protection everywhere in the house, when the sparkie eventually got around to testing the earth bonding, we found the problem. The house’s earth was not on spec. Fixed that, and the problem was sorted.
I presume your sparkie has already tested the earth on the DB?
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Yes, he did
Do you have any of those red surge arrestor plugs in your house?
I think he is referring to the meters that trip upon small amounts of backfeed (Conlog BEC23 and family) and I don’t think that’s the problem here. Your RCD is tripping, not your prepaid energy meter. That’s not the problem here.
Let me see if I can explain with a picture.
In this picture I have a standing leakage of 12mA. This, as noted earlier, is normal in any house, though 12mA is on the high side. I deliberately picked a high value. RCD’s will begin to trip at 15mA, and they MUST trip at 30mA. Between 15mA and 30mA you get nuisance tripping.
A disconnect sometimes cause a transient. For a second or so, because of changing voltage conditions, the leakage becomes higher. With a big heavy low-impedance grid hanging on the one end, I expect that transient to be higher.
The RCD needs a certain amount of ENERGY (watts multiplied by time) to trip. In this picture I am a bit naughty, the Y-axis has amps on it… so technically the shaded area is not really “energy”, but it illustrates the idea.
In this picture you can see that the transient on top of the standing leakage is enough to saturate the “tripping budget” (if I can call it that). For my example I shaded the area that represent the amount of energy that pushes the RCD over the edge, so that the transient exceeds it slightly.
To stop it from tripping, you either need to shorten the T component (ie make the transient narrower), or you need to lower the standing leakage (ie move the whole thing down).
What a transient/impulse/nuisance-tripping resistant RCD does, is it allows a higher transient spike as long as the “t” component is short enough.
But it is far cheaper to first lower your standing loss, and one of the simplest ways of doing that is to split your household loads over two RCDs.
Only then will I start looking at the expensive special RCD option. The type A-APR is over R4000.
Edit: Of course, another way to lower the standing leakage is get rid of surge arrestor plugs. Especially the one with the neon lamps in the red plug cover.
Guys, there is normally a very simple explanation for these trips. Out of hundreds of installations we only once had to install a high immunity RCD. normally a quick check of the house reveals the cause. We are often faced with these trips, but always sort it quickly. The difference between a normal power failure and a power failure with an Inverter is simple. The bonding between neutral and Earth is not broken during a load shed in a home without an inverter. In a home with an inverter, the bonding is non existent when the inverter disconnects and reconnects to the grid. This causes double the leakage current as all the caps between Earth and Neutral and Live and Earth needs to be be recharged in certain appliances/devices. The only real way to fix it is to find the device and remove it or to remove the cap from it.
I think a lot of the explanations in this thread over complicates the issue…
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I know why you say this, and have seen it work in your house, but I never even once had to resort to even this. We normal pin point the reason and fix it.
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In a manner of speaking I did the same thing. I figured out that I have appliances with unusually high leakage currents. The problem literally went away by unplugging the identified appliances during load-shedding (the coffee machine and laser printer). No amount of further searching was going to fix that, and because constantly having to remember to unplug things is a pain, I split the circuits…
In any case, the list I made earlier is still there, and it sounds as if he had a sparky do the first three steps already. But then, the kind of sparky who can divide-and-conquer this sort of thing is also rare…
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I had the same problem, but my earth leakage tripped when the power came back on. I spoke to my local electrical supplier and he asked what make EL I had, when I said it was a 63A ACDC he reckoned that it was almost 100% the problem. He sold me a 63A Chint and it has not tripped since.
I just want to report back that my Earth leakage issue is resolved. They ended up putting the second RCD and I have not experienced the tripping issue again. Thank you for all the advice as I suggested your solutions and we could resolve the issue.
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