Neutral earth bonding on backup systems.

[GCE]

There was a crowd that sat around a table and had the discussion that is how this article came about
https://ecasa.co.za/technical/neutra...ing-clarified/

Same way that there was a +/-6hr zoom meeting on Friday last week to get various manufacturers and others around a table for discussion over batteries with the view of putting out some sort of guidance which may still take awhile

[Isetech]

Either way it cant be that dangerous, otherwise the sale of these units would be halted, warning labels would be required exposing the dangers and there would be court cases.

Bottom line, just do what you think is right because at the end of the day it is not up to the electrician or installer to make the regulations.

Make sure whichever method you use, have the support of that group.

Has anyone done any tests with a meter ?

[Dylboy]

Only thing I have seen, is I had a perm neutral earth bond on the output of the inverter, I this time as a test put and inline 15Amp fuse in that perm bridge.

Went back the next day and that fuse had popped.... When I measured current at that time I was getting 9Amps when the grid was available, when the inverter went into island mode I had 0amps on the perm bond...

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[Justloadit]

Only thing I have seen, is I had a perm neutral earth bond on the output of the inverter, I this time as a test put and inline 15Amp fuse in that perm bridge.

Went back the next day and that fuse had popped.... When I measured current at that time I was getting 9Amps when the grid was available, when the inverter went into island mode I had 0amps on the perm bond...

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There should be no permanent Neutral/Earth bond on the output of the inverter if in Hybrid mode, or pass through mode, as the incoming supply would have this connection done at the transformer point.
Only when the inverter changes to Islanding mode should the Earth/Neutral bond take place, as the inverter now becomes the supply source, and for proper ELU operation, the Earth/Neutral bond now takes over.

[Dylboy]

Yes 100%, it was an install of someone else which had tripping issues and saw the perm neutral earth bond in which I did some tests on, i did then add a contactor to make and break.

Still was an interesting test and it came about a post from Isetech awhile back when he measured current on the earth so thought it would be a good test, it was quite awhile ago.

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[Derlyn]

I would hazard a guess and say you are going to be back there for a mains incoming neutral fault - Could be that there is a loose connection coming into the property and that every now and then it utilizes the inverter neutral due to the bonding

@ GCE. You are a foretune teller supreme.

Was called back on Friday for no mains power.
Main breaker faulty. ( Replaced )
After carefull inspection I noticed the telltale brownish burn mark on the neutral side of breaker.

I can only assume that the breaker was on it's way out and that there was a high impedance across the neutral contact inside.