Upgrade a Grid-Tied Solar PV System with battery. Solis RAI

[openspaceman]

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I cannot image that the inverter sold into mainstream the UK does not have those protections build in on the backup circuit.
In the case of power failure from what I read it immediately isolates just that one circuit so no way it can feed back to the grid.
Its not as if trying to do the whole house on UPS.

It is an anomaly which I, not being an electrician, do not fully understand but on a recent install for my daughter the electrician refused to enable the Emergency Power Supply of the inverter because of this earthing issue.

I cannot quite understand why a whole house earth (PME) cannot be installed in parallel with the earth provided by the network(known as TNS) .

The reason for the problem is that when the grid is disconnected the earth could also disappear so to use the EPS would mean there was no earth to anything connected to it. Thus there is a requirement for anything powered by the EPS to have its own earth arrangement which apparently has to be switched out when the grid is switched back on with its earth. This last bit is what I fail to understand as I cannot see why both earths cannot coexist.

There have been lengthy discussions on the point with major contributions by a lost member OldGreyBeard which may be searched

[Krill]

I am having everything fitted at the moment and they are installing an earth spike for the EPS tomorrow and that is in parallel with the grid earth.

Are you in the Midlands OSM? Happy to give you the contact details of my electrician if that would be helpful.

[openspaceman]

Thanks for the offer and reply but I am in NW Surrey but still struggling to find an electrcian to work on slightly out of the ordinary requests.

[Krill]

Thanks for the offer and reply but I am in NW Surrey but still struggling to find an electrcian to work on slightly out of the ordinary requests.

Oh well, best of luck to you!

[Tinbum]

I cannot quite understand why a whole house earth (PME) cannot be installed in parallel with the earth provided by the network(known as TNS) .

I have a feeling I read somewhere that that has actually changed recently and that you can have.

[spread-tee]

Thanks for the offer and reply but I am in NW Surrey but still struggling to find an electrcian to work on slightly out of the ordinary requests.

I know a good sparky who is based in Walton who likes a tech challenge and is very reliable, I can ask him if you wish?

I am not a sparks but I think the issue with multiple earths when using the EPS function with its own earth is that you cannot be sure the voltage is the same at both, there is no reference common to either, which AIUI can freak out the RCD devices. Don't quote me on this as this is only my take, but I do know earthing is a horribly complicated issue.

Desp

[Countrypaul]

Is there not a chance under fault conditions that the Grid supplied earth could be made live at the consumer end and therefore dangerous to someone who could be working on what should be an isolated system (isolated at the grid end)?

PS. I'm not a sparky, but it just looks like an obvious possibility to me.

[nowty]

Info here about EPS earthing arrangements.

https://electrical.theiet.org/wiring-ma ... e-systems/

[Tinbum]

An alternative view.

https://professional-electrician.com/te ... ms-niceic/

551.4.3.2.1 says;

[openspaceman]

Thanks for the offer and reply but I am in NW Surrey but still struggling to find an electrcian to work on slightly out of the ordinary requests.

I know a good sparky who is based in Walton who likes a tech challenge and is very reliable, I can ask him if you wish?

I am not a sparks but I think the issue with multiple earths when using the EPS function with its own earth is that you cannot be sure the voltage is the same at both, there is no reference common to either, which AIUI can freak out the RCD devices. Don't quote me on this as this is only my take, but I do know earthing is a horribly complicated issue.

Desp

Thanks he's only 10 miles away so I would be grateful for a number via a PM.

I am going to read Nowty's link but from my current position of ignorance I cannot see how a live to earth leak would affect an RCD by having two bonded earths.