Good day 

Over the weekend (while trying to spot this illusive green comet) I switched off my perimeter lighting while there were loadshedding. All of my LED spotlights had a faint but very noticeable glow while being switched off.

Google tells me it could be due to a "floating neutral". So using my multimeter I checked a few of my plug points in the house, and while being supplied by Eskom/municipality the difference between my earth and neutral is 1 V, and while on the inverter the difference is 11 V.

I have a Sunsynk 5kw inverter & battery combo, with this box below installed to bridge earth/neutral when eskom falls away. How can I check if this box is doing its job? 

https://segensolar.co.za/product/segen/protection-segen/ac-protection-box/earth-neutral-bridge-box-for-ac-protection-box/

I was under the impression that a floating neutral due to earth/neutral not being bonded is 100+ V.  Could there be another reason for this voltage difference between earth and neutral when Eskom falls away? 

My municipal supply is neutral/earth bonded in the supply box on my property to an earth spike.

Thanks for the help

No one with any ideas to what might cause this?

Sounds weird but switch off the electric fence and then test again. Heard of induced voltages from fence before. Never seen it but heard it from a reliable source to me

To me it sounds as if your inverter is not properly earthed, or that multiple earths are used.  You should only have one earth reference, meaning the inverter should use your DB-panel earth.  If your inverter is far removed (maybe in a garage) some people might rather slam  another earth spike into the ground.  There is no guarantee  that one spike might give you a good earth and secondly, it can differ due to ground currents.  I mean physically leakage currents in earth, ground, soil the stuff the Yanks refer to as "dirt".  LOL.    10 or 11V is more than enough for those LEDs to see enough forward current that they turn on dimly.

BTW, with electric fences, it is required to ground the fence energizer using THREE ground pegs, each one a distance of one meter minimum from each other.

I am not an electrician, but a retired electronic engineer.  There seem to be a lot of regulations that I am too stupid to understand or stupid regulations.....  you decide.  For instance, this bull of not combining 230VAC and LV DC in the same conduit.  That is SENSELESS.  But I guess I shouldn't complain.  If you look at US or UK wiring codes, they are 10x more strict.

It is interesting that in Germany, people do NOT need an electrical COC when selling/buying a house.  A COC is only required if/when modifications have been done to the electric system.

The world is turning mad with it's green agenda which is FAKE and I don't buy into it.  Not even solar panels are truely green, due to the exotic input materials and the finite lifetime.  However, now that we are all forced to jump onto this bandwagon, we should COMPLETELY re-write the rule books.  I always smile silently at the people (especially on this forum) that have these mega-installations.  Maybe the owners just have completely non-understanding wives....  that want, no, demand, that EVERYTHING works at the same time.  She wants to boil the kettle, run the washing machine, the micro and the dish-washer all at the same time.

There is no difference between an LCD and a LED TV.  They are both LCD.  But the old model uses CFL backlighting while the LED uses LED backlighting.  LED Backlighting consumes about 30% of what CFL does.  My point is this,  should you not rather throw out your 70W LCD TV and replace it with a similar sized LED TV for R 3000.  A 32-inch LED TV will run at under 20W.  And while you are at it, buy a TV that runs from a 19V laptop-type power supply.  Because then you can buy a R100 Boost converter and feed your TV straight from a 12V battery.  

The TV is just an example.  My point is, people are prepared to spend 150K+ on massive battery banks.  Why not spend only 100K on batteries and use 50K to replace old, inefficient technology.

I think future homes should use AC/DC hybrid wiring systems.  I HATE running an inverter 24/7.  The damn fan noise, the power wastage and the fact that HV AC is detrimental to human health.  OH, now I have blown it.  What a nut-case.  Who is he?  HaHa.  Well, go google the two medical conditions known as MCS (Multi-Chemical Sensitives) and EHS (Electro Hyper Sensitivity).  These two conditions often go together.  Read the story of Canadian song-writer Kim Palmer.  Then maybe, you will understand.

My opinion is that most things should run on LV DC.   12V is not ideal.  24V would be better.  AC distribution should NOT be always on.  Instead, it should be limited to things like vacuum cleaners, irons, power tools, etc. on a demand ONLY supply.  What I mean is, the inverter should be in sleep mode and only power up when a load wants power.  This would be simple to implement.  That's what the battery-backed up LED lights do, just in reverse order.  In fact, you get modules that power down a mains circuit and re-trigger on demand, used by the very people suffering from EHS...

On 2023/02/14 at 10:46 AM, Leonb said:

All of my LED spotlights had a faint but very noticeable glow while being switched off.

Map out your wiring, and where your switch (or day/night sensor) is connected in the circuit. If there is live running directly to your lights, and your switch is installed on the neutral (at some distance away from the lights), there will be enough capacitive coupling to earth (or neutral) for your lights to glow dimly (even if your switch is off). 

1 hour ago, Modina said:

To me it sounds as if your inverter is not properly earthed, or that multiple earths are used.  You should only have one earth reference, meaning the inverter should use your DB-panel earth.  If your inverter is far removed (maybe in a garage) some people might rather slam  another earth spike into the ground.  There is no guarantee  that one spike might give you a good earth and secondly, it can differ due to ground currents.  I mean physically leakage currents in earth, ground, soil the stuff the Yanks refer to as "dirt".  LOL.    10 or 11V is more than enough for those LEDs to see enough forward current that they turn on dimly.

BTW, with electric fences, it is required to ground the fence energizer using THREE ground pegs, each one a distance of one meter minimum from each other.

I am not an electrician, but a retired electronic engineer.  There seem to be a lot of regulations that I am too stupid to understand or stupid regulations.....  you decide.  For instance, this bull of not combining 230VAC and LV DC in the same conduit.  That is SENSELESS.  But I guess I shouldn't complain.  If you look at US or UK wiring codes, they are 10x more strict.

It is interesting that in Germany, people do NOT need an electrical COC when selling/buying a house.  A COC is only required if/when modifications have been done to the electric system.

The world is turning mad with it's green agenda which is FAKE and I don't buy into it.  Not even solar panels are truely green, due to the exotic input materials and the finite lifetime.  However, now that we are all forced to jump onto this bandwagon, we should COMPLETELY re-write the rule books.  I always smile silently at the people (especially on this forum) that have these mega-installations.  Maybe the owners just have completely non-understanding wives....  that want, no, demand, that EVERYTHING works at the same time.  She wants to boil the kettle, run the washing machine, the micro and the dish-washer all at the same time.

There is no difference between an LCD and a LED TV.  They are both LCD.  But the old model uses CFL backlighting while the LED uses LED backlighting.  LED Backlighting consumes about 30% of what CFL does.  My point is this,  should you not rather throw out your 70W LCD TV and replace it with a similar sized LED TV for R 3000.  A 32-inch LED TV will run at under 20W.  And while you are at it, buy a TV that runs from a 19V laptop-type power supply.  Because then you can buy a R100 Boost converter and feed your TV straight from a 12V battery.  

I think future homes should use AC/DC hybrid wiring systems.  I HATE running an inverter 24/7.  The damn fan noise, the power wastage and the fact that HV AC is detrimental to human health.

My opinion is that most things should run on LV DC.   12V is not ideal.  24V would be better.  AC distribution should NOT be always on.  Instead, it should be limited to things like vacuum cleaners, irons, power tools, etc.   That's what the battery-backed up LED lights do, just in reverse order.  In fact, you get modules that power down a mains circuit and re-trigger. 

Thanks. You raise a few interesting points and food for thought. I just think our lifestyle are of such a nature we want to do whatever we used to doing with the flick of a switch. 

I have many times had chats on just making a few adjustments and you can get along with a much smaller lower cost system.. A very common reply is NO. All or nothing. 

Edited February 15, 20233 yr by Scorp007

On 2023/02/14 at 8:46 AM, Leonb said:

Good day 

Over the weekend (while trying to spot this illusive green comet) I switched off my perimeter lighting while there were loadshedding. All of my LED spotlights had a faint but very noticeable glow while being switched off.

Google tells me it could be due to a "floating neutral". So using my multimeter I checked a few of my plug points in the house, and while being supplied by Eskom/municipality the difference between my earth and neutral is 1 V, and while on the inverter the difference is 11 V.

I have a Sunsynk 5kw inverter & battery combo, with this box below installed to bridge earth/neutral when eskom falls away. How can I check if this box is doing its job? 

https://segensolar.co.za/product/segen/protection-segen/ac-protection-box/earth-neutral-bridge-box-for-ac-protection-box/

I was under the impression that a floating neutral due to earth/neutral not being bonded is 100+ V.  Could there be another reason for this voltage difference between earth and neutral when Eskom falls away? 

My municipal supply is neutral/earth bonded in the supply box on my property to an earth spike.

Thanks for the help

 

16 hours ago, Modina said:

To me it sounds as if your inverter is not properly earthed, or that multiple earths are used.  You should only have one earth reference, meaning the inverter should use your DB-panel earth.  If your inverter is far removed (maybe in a garage) some people might rather slam  another earth spike into the ground.  There is no guarantee  that one spike might give you a good earth and secondly, it can differ due to ground currents.  I mean physically leakage currents in earth, ground, soil the stuff the Yanks refer to as "dirt".  LOL.    10 or 11V is more than enough for those LEDs to see enough forward current that they turn on dimly.

BTW, with electric fences, it is required to ground the fence energizer using THREE ground pegs, each one a distance of one meter minimum from each other.
 

Thanks. I will try to confirm where the installer picked up the earth for inverter, but he did not install any new earth spikes, so I think there is only one earth reference. 

The distance between the main DB in my house and where the inverter (incl.the N/E bridge) is is about 20m. He installed a 6mm 4 core surfix cable which has an earth wire of 2.5mm. If he picked up the earth in the main DB, could the distance between main DB and inverter be the reason for the potential difference between earth and neutral during backup power supply/loadshedding?

15 hours ago, clu said:

Map out your wiring, and where your switch (or day/night sensor) is connected in the circuit. If there is live running directly to your lights, and your switch is installed on the neutral (at some distance away from the lights), there will be enough capacitive coupling to earth (or neutral) for your lights to glow dimly (even if your switch is off). 

 

8 hours ago, YellowTapemeasure said:

 

Thanks for this.

But the glow is only during loadshedding when the inverter backup supply power. During normal operation when Eskom is online, there is no glowing of any led lights.

Might be that your supply to the LED's is lying alongside a long stretch of live wire going elsewhere and voltage is induced into the LED line. Not uncommon.

@Mako, yes you are absolutely right.  It is a real possibility.  We don't know how many flood lights are in use, but flood lights are relatively high wattage LEDs and are not as prone than small house bulbs.  On the other hand, 20m of wiring length is substantial and could add up to quite a bit of stray coupling capacitance.  However a 11V earth difference is also bit concerning.  I myself have no practical experience with such long cable runs and so I am in no position to know if 11V is out of the ordinary.  Only that 11V would be enough to cause LEDs dimly turning on. 

In an ideal world, the earth should carry zero current and thus have zero potential difference.  The real world mostly mis-behaves. 😀

3 hours ago, Leonb said:

 

Thanks for this.

But the glow is only during loadshedding when the inverter backup supply power. During normal operation when Eskom is online, there is no glowing of any led lights.

Next time, water your earth spike well, and let us know if they still glow.

On 2023/02/14 at 10:46 AM, Leonb said:

Good day 

Over the weekend (while trying to spot this illusive green comet) I switched off my perimeter lighting while there were loadshedding. All of my LED spotlights had a faint but very noticeable glow while being switched off.

Google tells me it could be due to a "floating neutral". So using my multimeter I checked a few of my plug points in the house, and while being supplied by Eskom/municipality the difference between my earth and neutral is 1 V, and while on the inverter the difference is 11 V.

I have a Sunsynk 5kw inverter & battery combo, with this box below installed to bridge earth/neutral when eskom falls away. How can I check if this box is doing its job? 

https://segensolar.co.za/product/segen/protection-segen/ac-protection-box/earth-neutral-bridge-box-for-ac-protection-box/

I was under the impression that a floating neutral due to earth/neutral not being bonded is 100+ V.  Could there be another reason for this voltage difference between earth and neutral when Eskom falls away? 

My municipal supply is neutral/earth bonded in the supply box on my property to an earth spike.

Thanks for the help

1) Can you confirm that "Signal Island Mode" is enabled


2) Does the RED led lights up on the Neutral Earth Bond box when grid is off?

3) Whats the voltage on the Essential Side (when grid is off):
L-N -> Expect 230V
L-E -> Expect 230V
N-E -> Expect 0V

Edited February 16, 20233 yr by system32

5 minutes ago, system32 said:

1) Can you confirm that "Signal Island Mode" is enabled


2) Does the RED led lights up on the Neutral Earth Bond box when grid is off?

3) Whats the voltage (when grid is off):
L-N -> Expect 230V
L-E -> Expect 230V
N-E -> Expect 0V

 

 

 

1) The signal island mode is not checked. Is it required when using this specific bridge box? Does it not engage independently from inverter when it detects that the eskom power is down? See wring diagram below:

 

2) Where on this bridge box is the "red LED" light to indicate bond?

3) I will check settings and voltages when at home later.

 

Thanks

The relay has to be controlled by the inverter (see info about delay below).

On my SunSynk 8k, there are 2 wires connected from the ATS240 points on the inverter to a relay in box that bonds N & E.
The SunSynk will activate the relay box when in Island Mode (grid goes off).
When grid returns, the SunSynk is programmed to delay ~60s (NRS requirement) before connecting to the grid and deactivating the relay.

 

Edited February 16, 20233 yr by system32

43 minutes ago, system32 said:

The relay has to be controlled by the inverter (see info about delay below).

On my SunSynk 8k, there are 2 wires connected from the ATS240 points on the inverter to a relay in box that bonds N & E.
The SunSynk will activate the relay box when in Island Mode (grid goes off).
When grid returns, the SunSynk is programmed to delay ~60s (NRS requirement) before connecting to the grid and deactivating the relay.

 

I believe this bridge box activates independently of the inverter. It seems to be a solution for any type of inverter that needs a bond, ie. does not need a signal from inverter. It seems to activate on the grid falling away.

It has a bare wire running inside saying "test point", but Im not sure how one is supposed to test the bond using this.

Maybe someone with knowledge of this specific bridge box can assist?

5 hours ago, system32 said:

1) Can you confirm that "Signal Island Mode" is enabled


2) Does the RED led lights up on the Neutral Earth Bond box when grid is off?

3) Whats the voltage on the Essential Side (when grid is off):
L-N -> Expect 230V
L-E -> Expect 230V
N-E -> Expect 0V

Slight hijack, but still on topic I think - I also have a glowing LED light which comes on during loadshedding (even if the switch is off) that is wired to the essentials on my Sunsynk (actually every circuit in the whole house is wired to essential and I manage loads with smart switches, but not sure that's relevant). When I test at my inverter on the load connections while loadshedding, I get L-N = 233v, L-E = 145v and N-E = 125v.

So this seems to be wrong, but what does this imply? That Earth-Neutral isn't bonded? Is it dangerous? Is this something the installer should come back to fix?

EDIT: also not sure if it's relevant, but I have no solar panels (and hence no exporting to grid). Only inverter and battery.

Edited February 16, 20233 yr by gu3st

14 hours ago, Leonb said:

 

 

1) The signal island mode is not checked. Is it required when using this specific bridge box? Does it not engage independently from inverter when it detects that the eskom power is down? See wring diagram below:

Not required, it operates independently.

14 hours ago, Leonb said:

2) Where on this bridge box is the "red LED" light to indicate bond?

On the relay itself.

14 hours ago, Leonb said:

3) I will check settings and voltages when at home later.

 

Thanks

1. As suggested by @system32 check your voltage between earth and neutral on the essential load.

2. Test the earth leakage. This is the acid test and the reason for the relay in the first place.

OK, so last night I did some tests. I cannot make sense of the results and am both very confused and worried:

1) During normal operation when the grid is supplying power, i.e no loadshedding

I get the following Voltage readings:

• N to L  = 214 V
• N to E = 1 V
• L to E = 216V

This is more or less what I expected, although a bit on the low side?

2) During loadshedding when Inverter supplies power to essentials from battery. This is when the N/E bridge box is supposed to work:

Now this is where I get lost. I get different readings when I switch around the red and black leads of the multimeter

• N to L = 227 V (black lead on N; red lead on L; and vice versa)
• N to E = 8 V (black lead on N; red lead on E)
• N to E = 220 V (black lead on E; red lead on N, i.e. leads swapped around)
• L to E = 235 V (black lead on E; red lead on L)
• L to E = 20 V (black lead on L; red lead on E, i.e. leads swapped around)

The tests above was done on various plug points in the house. I have not opened any DBs, etc to test light or other circuits.

From what I understood previously, on AC, even if you switch the pos/neg leads around, the Voltage reading should be the same. And yes, the selector is on AC, not DC.

I cant make sense of the above. Any ideas before I call out the installer, or another electrician?

The earth leakage breakers do trip when I press test button, both when grid is on and off. There is one on essentials and one on non-essentials.

The installation was certified by 3rd party electrician with COC covering the new installation.

 

 

8 minutes ago, Leonb said:

OK, so last night I did some tests. I cannot make sense of the results and am both very confused and worried:

1) During normal operation when the grid is supplying power, i.e no loadshedding

I get the following Voltage readings:

• N to L  = 214 V
• N to E = 1 V
• L to E = 216V

This is more or less what I expected, although a bit on the low side?

2) During loadshedding when Inverter supplies power to essentials from battery. This is when the N/E bridge box is supposed to work:

Now this is where I get lost. I get different readings when I switch around the red and black leads of the multimeter

• N to L = 227 V (black lead on N; red lead on L; and vice versa)
• N to E = 8 V (black lead on N; red lead on E)
• N to E = 220 V (black lead on E; red lead on N, i.e. leads swapped around)
• L to E = 235 V (black lead on E; red lead on L)
• L to E = 20 V (black lead on L; red lead on E, i.e. leads swapped around)

The tests above was done on various plug points in the house. I have not opened any DBs, etc to test light or other circuits.

From what I understood previously, on AC, even if you switch the pos/neg leads around, the Voltage reading should be the same. And yes, the selector is on AC, not DC.

I cant make sense of the above. Any ideas before I call out the installer, or another electrician?

The earth leakage breakers do trip when I press test button, both when grid is on and off. There is one on essentials and one on non-essentials.

The installation was certified by 3rd party electrician with COC covering the new installation.

 

 

You either have a faulty multimeter or leads. Put your multimeter on ohms scale short the red and black leads together and see how many ohms you reading keep them shorted out and wiggle your leads to see if your ohm readings change. You should have < 0.5 omhs if your leads are good. On AC doesn't matter what lead is on L or N the reading must be the same

In German there is a saying:  Wehr Mist, mist viel Mist.   - He who measures, measures a lot of sh!t.

You need to realise that electric lines carry not clean textbook stuff but very complex signals.  They hardly ever ONLY contain AC or DC.  There are often small DC components riding on AC and vice versa.  We talk about 230VAC but the peak voltage of a sine is actually 324V.  Cheap meters "assume" a pure sinewave and measure the peak and then multiply by 0.707.   More expensive true RMS meters have special chips to calculate the true RMS value from any random waveform.  But this is all still the easy part.  Your 50Hz AC might carry HUGE high frequency noise components, right up into the KHz and even early MHz regions.  Only an oscilloscope would start giving you the fuller picture, and even then, the operator needs to consider how wide he wants to set the bandwidth window.

I am not trying to confuse here, merely want to point out the complexities.  Power Electronics and switching noise go hand-in-hand.

However, I am at the moment at a loss of words to try and explain massive differences on a AC meter reading by flipping the two meter probes.  Something is ammiss.  I would need to think about this.  Have you maybe got another meter you can try?  Sometimes the meter leads can break without you realizing it.  DC would then measure zero, but not AC.   A broken cable will have capacitive leakage across the break.  This capacitance will be enough to give you AC readings, even at low utility frequencies, i.e. nominal 50Hz.  But these readings will obviously be way out.  Cables always break where they flex the most, at the connector or probe junctions.  In a case like yours, one needs to check everything.

Thanks. I will try to borrow or buy another multimeter, and revert.

Try and get hold of a Fluke multimeter if you measure Ac you measure Ac transient will not influence the reading with a reputable multimeter

On 2023/02/16 at 8:39 PM, gu3st said:

Slight hijack, but still on topic I think - I also have a glowing LED light which comes on during loadshedding (even if the switch is off) that is wired to the essentials on my Sunsynk (actually every circuit in the whole house is wired to essential and I manage loads with smart switches, but not sure that's relevant). When I test at my inverter on the load connections while loadshedding, I get L-N = 233v, L-E = 145v and N-E = 125v.

So this seems to be wrong, but what does this imply? That Earth-Neutral isn't bonded? Is it dangerous? Is this something the installer should come back to fix?

EDIT: also not sure if it's relevant, but I have no solar panels (and hence no exporting to grid). Only inverter and battery.

N-E = 125v is bad. Does your earth leakage work when loadshedding? Test it and if not get the installer back.

Had the same problem at a clients house, faint glow from the LED lights during load shedding, found out that the neutral-earth relay wasn't working, voltage between neutral-earth was 111 volts, sorted out the relay issue and all was good.