Earthing arrangements when installing battery storage

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Not sure which topic to put this (and other battery storage related issues), so move if required.

I would appear that the Battery Storage revolution is upon us and whether we like it or not, people are going to start fitting these. If it turns out I'm installing them, I want to make sure I'm doing it right.

I know some on here are totally against it at moment, but as I say, it will probably happen regarless of our view.

So, lets kick the questions off with earthing. In particular earthing arrangements when a backup system is installed for when the grid fails. From what I have found out so far, once the grid fails you need to have a changoover switch, whether it be manual or automatic and as part of the changeover, when the generator (in our case a battery system) is brought in the Neutral and Earth connections need to be linked.

That is pretty much as far as freely available information goes. So, my question is, what else?

If the grid Earth connection is lost (afterall backup is for in case of lost grid) then there is no connection to the mass of earth. Wouldn't be an issue if we were floating in the sky not touching earth ourselves or using services that do contact earth. My assumption would be to fire a spike in, but where? adjacent MET and connect to MET? From memory the DNO don't like you adding earth connection after a TN split, though I could be wrong. Do we need to bond the body of the battery inverter so that it is just the same potential as the other services?

I can only assume that this is same no matter what the secondary generator is, battery, diesel, water @Canoeboy.

Any info would be greatly appreciated.

 
Exactly, it has to be kept seperate, So how to provide an earth that is seperate? If you spike on generator side of changeover then no service bonds are connected thus you have circuits with different potential CPC to other services (water, gas). I guess there will be a connection via the CPC of the cable connecting generator to Cu but this is way smaller than main bonds. Am I just looking at it wrong?

 
change over switch will keep lives separate, but you cant switch an earth so any earthing arrangements would be common, so if you fit a rod for battery, then it would also act as a rod on the TN supply

you could fit a rod and ditch the DNO earth and keep TT for mains supply and TNS for battery

 
the rod will need to connect to MET, along with DNO earth if used. the 20 ohms bit is fairly common for this, and the DNO use it for the rods at their substations

 
Canoeboy said:
Common Earth Using DNO Earth and Rod the Install as well, do an Ra, Do Zs on both supplies, jobs a good un.......
That's what I have,

TNCS with localised PME,

my assessor was quite impressed with the system, 

 
Reg 444.4.6 says that an install with 2 supplies should only have 1 earth connection, this is what through me. Does it simply mean that the rod must connect to the same MET as the grid earth?

Wow, recommended that the earth electrode does not exceed 20 Ohm.....


the rod will need to connect to MET, along with DNO earth if used. the 20 ohms bit is fairly common for this, and the DNO use it for the rods at their substations


Substation_zps621510e4.jpg


 
Canoeboy said:
Common Earth Using DNO Earth and Rod the Install as well, do an Ra, Do Zs on both supplies, jobs a good un.......




Would that rod be at grid incomer connected to MET or near Battery Inverter (the generator)?

 
Would that rod be at grid incomer connected to MET or near Battery Inverter (the generator)?


Would that rod be at grid incomer connected to MET or near Battery Inverter (the generator)?
Do both,

:C

I have a rod at incomer and a rod at shed end,

You can never have too many roddings, ;)

 
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