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Posted By Topic: Multiple earths

mattsullivan
Aug 07 2019 18:36

We have an off grid power supply with a 48 volt battery set, some solar, and a windmill. I am about to add another solar array, but I am unsure what to do with earthing.
The house currently has one ground rod, but the electrician did not tie neutral to the earth bus bar. I cannot recall what his reasoning was as this was 12 years ago.

At my shed where the inverter and batteries are stored he drove another earth stake, and the shed equipment is tied to that. My question(s) are -

1/ should i drive another earth stake at the new solar array, or tie this array into the shed stake?

2/should I tie the earth and neutral at the house?

I am also intending to get one or two of these
http://www.indepower.co.nz/files/FW-SP-datasheet.pdf

Any advice appreciated.
Matt


   

dlink
Aug 07 2019 18:51

you would need to earth the frame of the array, not the d.c. itself from the array. i assume your batteries have the negative tied to earth ?
Might pay to get a electrician involved who does abit of solar of grid system.
   

AlecK
Aug 08 2019 08:35

The answers are in AS/NZS 5033, which your array will be required to comply with under electricity regulations.

And if the open-circuit array voltage is above 120 V, installation requires an electrician.
   

mattsullivan
Aug 08 2019 20:24

Thanks Aleck k. Can you send me a copy of the standard?
Thanks,
Matt
   

DougP
Aug 08 2019 22:45

You can buy the standards from here.


https://www.standards.govt.nz/
   

mattsullivan
Aug 09 2019 07:20

Yeah I realise that. Problem is there are hundreds of standards, and I do a lot of things. If I have to buy one every time I want to do something, I will spend about $1,500/year on them. The fact that people are excluded from the standards they are supposed to comply with is frankly ridiculous.
   

AlecK
Aug 09 2019 09:17

Anyone with current practising licence for electrical work can access it free (or rather, paid for by their licence fees).
So if you have a POL, you don't need to buy. (And if you don't, you're not who this website is aimed at)

Actually I agree that Standards that have been cited such that they are de-facto law should be at least subsidised by Govt; on grounds that the primary benefit of having eg electrical installations consistently safe is the public, rather than the practitioners who are required to follow the Standards. But they're not.

So don't expect those of us who've paid to pass on the info for free. That would be breaking the copyright laws; but it would also be commercial suicide. Same for the hard-earned knowledge & experience tradespeople have - knowing stuff is how we make our living.