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Now this is really interesting.

The PV panel input was disconnected and the E/L in my inverter DB didn't trip today

BUT

At 14:30 I heard a knocking coming from my council DB, turns out the geyser timer pulls in a contactor at the exact time.

Seems like as soon as the geyser timer is on and the PV panels are connected the inverter E/L trips.

The geyser, timer and contactor are all in my council DB and are fed from before the council E/L.

Tomorrow I will connect the PV panels again and at 14:30 when the inverter DB E/L trips I will turn off the geyser timer and see if the inverter DB E/L will stay up.

Fingers crossed!

I'm a little confused, the Council DB should only have a mcb and a KWH meter, your main DB is where your geyser controls and the ELR should be installed.

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I'm a little confused, the Council DB should only have a mcb and a KWH meter, your main DB is where your geyser controls and the ELR should be installed.

When I refer to my "council DB" I am referring to the DB board in my home which is fed by council, not the meter box on the street which houses the mains MCB and KWh meter

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Who did the DB wiring for you?

Was it done from a drawing perhaps?

 

Reason I ask is I see there is a bypass switch for inv and normal feeds.

Now, when running from the inv feed, where does the inverter gets it's neutral from?

With certain inverters you have to tie the neutral output of the inv to ground, if I am not mistaken????

 

Do you still have an E/L in your DB for normal supplies, or is everything in the house now on inverter power?

It could be that there is an issue on either the geyser contactor wiring or the geyser itself. Somehow this is feeding back via the E/L?

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Ok, think I figured it out.

You have a live or neutral that is crossed before or after the E/L unit.

So what this means is you perhaps have a live from after the E/L feeding a circuit. The neutral of this circuit is then connected before the E/L unit.

It can also be the neutral.

 

The E/L unit works on sencing the diffence in current between live and neutral.

If the diff is bigger than 30mA it thinks there must be an earth fault somewhere and trips.

 

Happy hunting.

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@ Wetkit - I did the wiring myself no drawing I am afraid, I did it on the fly ;) You were spot on, it was a neutral on the wrong neutral bar

 

Problem solved, turns out the neutral conductor of the geyser was connected to the inverter neutral bar and the live conductor was connected to the council db.

Moved the neutral to the correct neutral bar and hey presto, works like it should

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Ok, so heres the next issue...

When testing today I found that I was getting 240v between live and neutral but only 170v between and 70v between earth and neutral

This was on the inverter output

Should I brigde the earth and neutral output at the inverter?

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This condition is known as a floating neutral and this is going to get complicated. Ships commonly have floating neutrals but there is some inherent danger. In a floating neutral situation very often when there is a Live-Earth fault no protection will trip as there in no return for "fault currents".   In terrestrial systems if you have a floating neutral and it should be bonded to earth. The earth wire needs to go to source but if you are operating from the battery your inverter is the source and in bypass mode grid is the source. So folk have a relay on earth activated by Eskom. The has been much discussion on this forum and mybroadband  forum as to a solution - it is not that easy.

 

I live on a farm and so my solution is relatively simple. The inverter neutral is earthed and the earth runs back to the generator and to the earth mat. So the earthing is either to the inverter or to the generator if it is running. The problem city folk have is that Eskom can be present but depending on the settings on the inverter Eskom may not be the source. Whereas with me if my generator is running it will always be the source.    

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This condition is known as a floating neutral and this is going to get complicated. Ships commonly have floating neutrals but there is some inherent danger. In a floating neutral situation very often when there is a Live-Earth fault no protection will trip as there in no return for "fault currents".   In terrestrial systems if you have a floating neutral and it should be bonded to earth. The earth wire needs to go to source but if you are operating from the battery your inverter is the source and in bypass mode grid is the source. So folk have a relay on earth activated by Eskom. The has been much discussion on this forum and mybroadband  forum as to a solution - it is not that easy.

 

I live on a farm and so my solution is relatively simple. The inverter neutral is earthed and the earth runs back to the generator and to the earth mat. So the earthing is either to the inverter or to the generator if it is running. The problem city folk have is that Eskom can be present but depending on the settings on the inverter Eskom may not be the source. Whereas with me if my generator is running it will always be the source.

Thanks Chris, I looked in up on the my broadband forum and it's left me with more questions than answers.

It seems as though I have opened a can of worms!

Is there anyone who is grid connected who managed to sort this issue out?

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What I have done is to have my whole DB on the Inverter. So the inverters go to the EL bar the same way as the rest. I hooked up a wire from the closest wall socket. Then I tested it all with a trip meter on eskom and on inverter and all is working 100%

Thanks Jaco, I will read through your post and have a look see ;)

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Ok, so when you running a battery inverter like the Axpert, there is no Neutral link between mains and inv output, when the inv is running from batteries.

Reason for the strange voltages is that the inv and mains might not be running 100% the same frequency.

 

If your house earthing is good, you should be able to tie the inv output neutral to the inv earth. Do this right at the inv output connections.

That should reference your neutral to ground.

This is the main reason why these inv cannot be supplied from an E/L unit.

If your home main breaker is an E/L unit, you might pick-up issues here.

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Spanner in the works.

It's illegal to bond the neutral to earth in any installation, can only be done by the supply authority.

I have done it on my inverter, but the ideal situation would if all inverters had automatic neutral to earth bonding when the power supply fails.

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Spanner in the works.

It's illegal to bond the neutral to earth in any installation, can only be done by the supply authority.

I have done it on my inverter, but the ideal situation would if all inverters had automatic neutral to earth bonding when the power supply fails.

 

I'm glad you've mentioned this. We've discussed this for a very long time and the discussion is still open and unresolved. The automatic bonding options can only be used on non-hybrid inverters e.g. the Axperts. Since loadshedding started in SA there were obviously thousands of Axpert inverters installed in this country and all those installations had to be COC'd - how was that done - referring to the earthing / bonding in the installations?

 

How do you need to connect / earth / bond in the case of a true hybrid installation like the Imeon and infini?

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Good point superdiy, how were COC's issued?

The issue with the grounding relay on the inverter output is that it will only bond the inverters neutral output to the inverters earth output when there is no council power.

So during a sunny day while running off of PV if eskom is available the grounding relay won't be active.

What about doing something with an earth spike and disconnecting the council earth to the inverter input? Or is this going to cause more issues than its worth?

 

All my appliances seem to be running 100% even with the floating neutral, what would happen if I just left it as is, could it cause damage or harm? I recall reading somewhere that the earth leakage and circuit breakers won't trip if you have a floating neutral.

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I'm not an expert here, but I think it depends on isolation.

 

If for example the output is completely isolated from the real ground (on which you stand with your bare feet), then there is usually no problem with a floating ground. Lots of cheaper inverters work like that.

 

Of course no circuit is ever completely isolated from real ground, the air acts as a dialectric for a large air capacitor and capacitors pass AC... but the actual path to ground will be tens of mega ohms, so close enough. Best is to measure with a milliamp meter how much actually flows.

 

If it is ground referenced in some manner, then there might be a problem I think. You now have an appliance that is grounded to the case of the inverter, but the case does not sit at 0V relative to the real ground. It might sit at 90V or so (this is what mine shows when the bonding relay is open). Now if you touch this appliance, that 90V will push a current through your body to real ground (so you get that tickley feeling). Usually this leaky ground is not capable of sourcing much current, so it's unlikely that it will kill you... but that's not how we do things :-)

 

Secondly, your ELB works on a difference in current between live and neutral. Usually it needs a difference of around 20mA. When neutral is bonded to earth, you work with a peak of 315V (230VRMS ~= 315 peak), and ohms law says a human body of around 315/0.02 = 15.75k-ohm.

 

But suppose you now have a floating ground, and it's floating at 120V relative to real ground. If the same 15k-ohm human touches a life wire now, you only have 10mA flowing through the human. Not enough to trip the breaker, but rather uncomfortable to the human in question.

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Spanner in the works.

It's illegal to bond the neutral to earth in any installation, can only be done by the supply authority.

I have done it on my inverter, but the ideal situation would if all inverters had automatic neutral to earth bonding when the power supply fails.

 

Get a Victron Multiplus. No... check that. Go see your bank manager. Get a loan. Or sell a kidney. Then get a Victron Multiplus. They come with a bonding relay that does exactly what you describe.

 

:-)

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You know, everywhere I have read over the years, trying to grasp the concepts with my limited knowledge re. isolation, earthing, bonding neutral and earth or floating earth et al, I wonder: Is the earth isolated, is it neutral, floating in space? Is the earth earthed? How, it is in a vacuum?  :P

 

And what about solar flares?

 

It inevitably boils down to a highly technical discussion, debate or worse, an argument, with no clear cut and dry answer for nincompoops like me, bar, that I will be shocked to death, my family is in danger, so you have to do this earthing thing yet I am not an electrical engineer, need an answer that I 'get'.

 

Worst is when a electrician (make that 4) cannot explain to me in 2 sentences, how earthing works when asked some daring questions, that can stand up to the scrutiny of the www's discussions. :D

 

I am so fo_ked, not?

 

So now I sit and ponder. How long did it take the engineers to figure out how to safeguard a house that I can buy anything in a shop, connect a plug to it and it works, and if I do something stupid, I still live, T&C's apply?

 

AHA, wait, T&C's apply!?

So your family is safe? Why can a baby put their fingers into a plug? Why have such large holes, for baby fingers, in wall sockets?

Why is it when you pull a plug out, you can touch the live and neutral with your fingers? Seems to me a plug has a design flaw.

 

So, it is not as safe as it could be, ne? There are flaws in this design, not?

 

Now, having poured a glass of wine, I am on a roll!!!

 

So I wonder whilst sipping some wine, why is it not as simple with solar goeters, to take a earth wire, connect it to the DB boards earth busbar, and be done? O wait, it depends on the equipment ... isolated floating neutral, with live music and all that, and solar panels, nee boet, lots of money for that 2nd rod because ... ag, I lost my train of thought.

 

So I finish the wine and go to bed, but only after touching my servers PSU, standing bare feet on the tiles, feeling that reassuring tingling of solar energy flowing through my veins.  :D  :D  :D

 

Ps. For the silent readers out there, for the other floored newbies like me, like this post if you are with me, or touch a live wire in support, feel the soothing power of 'THE Mistress'!!!  :P

 

Pss. Wait, get a Victron!

SWAMBO said no, she needs a overseas holiday, a fridge, new dress and shoes to match, a perm and facial ... cheaper than a Victron, for my project is officially over she said.

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Spanner in the works.

It's illegal to bond the neutral to earth in any installation, can only be done by the supply authority.

I have done it on my inverter, but the ideal situation would if all inverters had automatic neutral to earth bonding when the power supply fails.

 

I cannot see why this is such a big problem.

At my incomming box to the house, the neutral is bonded to earth.

So if I do it further down the line too, why the fuss?

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I cannot see why this is such a big problem.

At my incomming box to the house, the neutral is bonded to earth.

So if I do it further down the line too, why the fuss?

 

There might be more reasons, but I'll try to explain the most obvious one - bear with me.

  • In a standard installation neutral and earth is bonded before the main ELR
  • Neutral and live (current carrying) conductors are usually one size thicker than the earth conductor
  • If you make another neutral-earth bond down the line and the neutral conductor between the two bonding points fail - e.g. because it was damaged or cut or because of a bad connection somewhere, the thinner earth conductor will be carrying the current, which might be too much for the thinner cable and which might cause over-heating and / or fire etc. etc.
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You know, everywhere I have read over the years, trying to grasp the concepts with my limited knowledge re. isolation, earthing, bonding neutral and earth or floating earth et al, I wonder: Is the earth isolated, is it neutral, floating in space? Is the earth earthed? How, it is in a vacuum?  :P

 

I am tired so I hope this makes sense. It does not matter what the voltage of the earth is. Its voltage relative to you is 0V. Same as the bird sitting on HT wire. The bird is at thousands of volts but is not touching or close to something earthed and so is not conductive.

 

Worst is when a electrician (make that 4) cannot explain to me in 2 sentences, how earthing works when asked some daring questions, that can stand up to the scrutiny of the www's discussions.  :D

 

Perhaps this farmer can achieve this elusive goal. Pity you so far away since I find that a "snotklap" to the side of the head helps when one is explaining something. At least the receiver of said "snotklap" pretends that he understands and you feel good about yourself since you have managed to convey a complicated concept in simple terms and your assistant now has grasped the concept. Tomorrow you discover he hasn't a cooking clue what you were on about but at least you had the momentary belief that you had made a breakthrough. :D By the way it won't be two sentences. 

 

Initially electrical systems were ungrounded but over-voltages were a problem caused by static, surges and lightning amongst other things. The solution was to ground the system. Here is a short video to demonstrate grounded and ungrounded systems.

 

 

The problem was now there was a real danger that someone's body would be a conductive pathway via the earth back to source for stray current. This only occurs in ungrounded systems once there are two faults to ground. However, the nature of an ungrounded system is that the first fault can go unnoticed. It usually arcs adding to the over voltage dilemma.

 

Hence the ground wire which provides a highly conductive alternate pathway for stray currents NOT to ground but to source (Eskom or generator, invertor etc.). 

 

Example: My granny's toaster has lovingly been handed down from one generation to the next and the vintage cloth covered conductor is a bit old, In fact there is a place where the insulation is broken and the neutral wire makes contact with the metal case of the toaster. As my missus pushes down the handle to toast  a slice of bread the whole toaster's metal case and handle is energised. Since the toasters has an earth wire the pathway back to source via the wire is in milliohms. My missus has just woken up and is barefoot on the tiled floor but her body's resistance is 10 000 ohms. The bulk of the current flows in the earth wire. There is a massive difference between current flow in the live and neutral and the EL breaker trips almost instantaneously. If she is lucky she will not even feel that tingling feeling.

 

If you want to understand grounding/earthing/bonding etc. Visit Mike Holt's Youtube page.

 

Here is a little titbit

 

 

Edit: Having been on the forum since 2013 you hardly pass as a newbie TTT. You are definitely an "ou man".

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