Poor Neutral/Earth Bond - Stubborn Nuisance Trips

[Justloadit]

Just a note about all new electronic equipment.
They are usually fed with an SMPS (Switched Mode Power Supply) due to universal input, cost and physical size.
One way of getting to pass the EMI limit specifications is to add a small capacitor between the secondary negative line and the incoming rectified negative line, and some of the systems depending on the type may have a capacitor to earth to reference the secondary side to earth. You can usually note this when you touch the chassis of 2 computers and get a tingling feeling, or noted a spark when connecting 2 computers via USB or in the old days RS232. Use you AC tested to measure the voltage between your PC chassis and Earth to see this.
A number of these SMPS connected could increase the leakage current from Neutral to Earth when there is a spike somewhere in the electrical system, which could cause the RCD to trip.

[Ewaldvdh]

Just a note about all new electronic equipment.
They are usually fed with an SMPS (Switched Mode Power Supply) due to universal input, cost and physical size.
One way of getting to pass the EMI limit specifications is to add a small capacitor between the secondary negative line and the incoming rectified negative line, and some of the systems depending on the type may have a capacitor to earth to reference the secondary side to earth. You can usually note this when you touch the chassis of 2 computers and get a tingling feeling, or noted a spark when connecting 2 computers via USB or in the old days RS232. Use you AC tested to measure the voltage between your PC chassis and Earth to see this.
A number of these SMPS connected could increase the leakage current from Neutral to Earth when there is a spike somewhere in the electrical system, which could cause the RCD to trip.

Thank you to you and to everyone else on the thread; the guidance and advice is appreciated. I also want to add that my replies are made with the intent to not discount any guidance or advice; it is in the interest of accounting for where I have given consideration prior; my motivations based on my own limited understanding and steps taken to try and resolve this nuisance trip issue.

I will admit that the bulk of the technical aspect of what you are describing is while fascinating for me; has mostly gone over my head. I understand the absolute basics only around the use of bridge rectifiers; converting AC to DC and the use of a step down transformer; adding to that only that I have an awareness that there are generally smoothing caps used to normalize the wave form and some additional filtering and circuit protection added. I know only enough about modern circuits to be able to identify components; do some basic checks with a multimeter and if there is visible damage to a component to desolder and replace and hold thumbs it doesn't go boom. However I appreciate the knowledge share and like I said; it is an area of interest. I do want to point out that it is an area of consideration; having encountered less expansive writeups on this topic before; coupled to a lifetime of building up desktop PC's and experiencing the tingles and arcs you refer to, leading me to the fact that all the compute devices in my house that would normally be accompanied by switch mode power supplies are quality units; equivalent to Corsair; if not Corsair psu's; I made sure of that. The smaller compute devices only has linear outputs on their PSU's; if the terminology is correct. I got rid of the hi-fi's; surround sound systems etc. [or to be more correct; I didn't replace them after these went boom when Eskom pushed their 380V down my line and the insurer noted that because these have not been listed it isn't covered]

[Ewaldvdh]

Just a note about all new electronic equipment.
They are usually fed with an SMPS (Switched Mode Power Supply) due to universal input, cost and physical size.
One way of getting to pass the EMI limit specifications is to add a small capacitor between the secondary negative line and the incoming rectified negative line, and some of the systems depending on the type may have a capacitor to earth to reference the secondary side to earth. You can usually note this when you touch the chassis of 2 computers and get a tingling feeling, or noted a spark when connecting 2 computers via USB or in the old days RS232. Use you AC tested to measure the voltage between your PC chassis and Earth to see this.
A number of these SMPS connected could increase the leakage current from Neutral to Earth when there is a spike somewhere in the electrical system, which could cause the RCD to trip.

Maybe a question here - would it be worth replacing the RCB with an SI unit; and would you perhaps be able to guide me to one that will fit on a mini rail?

[Justloadit]

Maybe a question here - would it be worth replacing the RCB with an SI unit; and would you perhaps be able to guide me to one that will fit on a mini rail?

According to the statements made about the SI unit, it may be a viable option.

[Alfred M]

Day night switches and motion detectors all small electronic devices use x- rated capacitor supply or dropper power supply where the low voltage is not mains isolated faulty day/ night or motion detection could also be problematic for RCD's.

is

[Ewaldvdh]

Day night switches and motion detectors all small electronic devices use x- rated capacitor supply or dropper power supply where the low voltage is not mains isolated faulty day/ night or motion detection could also be problematic for RCD's.

is

Thank you again; that is also valuable input Haven't considered that. I do have a Sonoff smart switch on the my Garage DSUB [outside light] and 2 on my Pool DSUB [Pool Timer and Light]; assuming the same premise could be valid for these. I did get rid of the day/night switches; [removed the Day/Nights because they were reducing the lifetime of my energy savers and replaced those with smart timers {at dusk they couldn't make up their mind as to whether or not they should be on/off}; {never fitted security lights, read too many Andy McNab books for that } House internals does have some Sonof switches as well but the lights are wired outside earth leakage

[Justloadit]

is

Just a point to note. The "Gnd" symbol in electronics, does not necessarily mean that it is a earth Connection.
It means a common point for all the electronics of the respective schematic which are tied together.

In the circuit shown above, joining the electronics to earth would destroy the bridge rectifyer.

[Alfred M]

Just a point to note. The "Gnd" symbol in electronics, does not necessarily mean that it is a earth Connection.
It means a common point for all the electronics of the respective schematic which are tied together.

In the circuit shown above, joining the electronics to earth would destroy the bridge rectifyer.

Yes i agree need to remove that symbol these circuits are all double insullated i have repaired quite a few of these supplies extreme care should be taken on these dropper supplies as the low voltage side is not mains insulated the series resistor on the neutral side is for current limiting that normally go open curcuit and some mov's either burn black and open curcuit but the x rated capacitor on the live side normally survives. These supplies work but with all the spikes we experience during load shedding i replace quite a lot of day/night switches and motion detection lights. These supplies can only work on low current devices but not the most reliable.

[Ewaldvdh]

That prepaid meter only working on earth and not on neutral is a bit telling.

Make sure that all neutrals are wired to the correct neutral bar (the one related to where the live is coming from).
While a crossed neutral on a live coming on the load side of an RCB will trip instantly, we recently had an instance of a neutral connected to the municipal supply neutral bar while the live was fed from the inverter (light circuit so it wasn't on earth leakage). When the municipal supply dropped, no problems were experienced. But when the municipal supply came back on, the RCB tripped as the inverter crossed to bypass mode (despite this neutral problem being on the load side of the RCB). Moving the neutral to the neutral bar for the inverter for circuits not on earth leakage solved the problem.

Good Morning Dave. Apologies for the delayed response.
Thank you as well

I went with solar because of the continuous and near everlasting supply issues from my municipality feed.

The Live/Earth on the meter was an issue well before I went the solar route; in fact it has been an issue since the municipality gave my neighbors their second phase that they magically manifested out of thin air with no meters.
The trips existed way before I went the inverter route. Will check again though that there isn't a crossing over a you describe in your thread to to make sure I exclude that.

[Ewaldvdh]

Not sure why the earlier post today did not go through; although it might have been due to a slightly frustrated tone; not sure if the moderators picks up on that. I will try to be a little more moderated.

As of yesterday AM I haven't been able to have my municipal feed switched on.
Did test suggested isolated inverter e.g. running on Eskom only > still tripping
Did my normal test isolating municipal feed e.g. running on inverter only > no trips
measured 0.8 amp on municipal line between Neutral and Earth when isolated e.g. not connected to my internals > not sure if this is a valid test but there you go
measured 18V on municipal line between Neutral and Earth when isolate e.g. not connected to my internals
Eskom Voltage on Live/Neutral jumping between 140V and 270V