Hi there,

I'm looking at having a 5kv LuxPower inverter installed - and from the two contractors I've spoken to, I need to have the backup power's DB board installed my garage near the inverter, due to space issues near my actual DB board (not enough).
They plan to have our lights and plugs running on the inverter, leaving the stove and geyser off.

From my understanding, they need to run a flat twin-earth cable from the inverter through my roof to the main db board, then run another flat twin-earth cable back from the DB board to the one in the garage (bringing those lights and plugs back), so that the inverter will be the 'master' of those items.

On the one quote, I see it's been quoted as 4mm wire needed.

I want to go up into my ceiling and run a neat 6mm flat twin-earth in my own time (not connected), so that one end is out by the garage, and the other end is available by the DB board for them to use... my roof space is really small, and I enjoy being up there (weird, I know).

I just don't know how many I need to run.

On the DB board, it's 3 'switches'... one for lights, two for plugs. Is that enough to go onto one cable? Plus the other one for the inverter?

So two x 6mm cables... should I run three just because? Or is two enough? Do they need to be inserted into any kind of tubing?

 

Sorry if this is confusing.

TLDR; I want to save my contractor some time (and try avoid them going into my ceiling because it's super cramped), and laying the flat earth cables myself (not connecting them).

The Earth conductor has to be able to dissipate all the energy in case of a fault.
So the earth conductor should be at least the same size or larger in mm sqr. as your current carrying conductors.
The earth cable must be able to handle a short circuit to earth without the potential of the earthed (metal) parts exceeding "touch" voltage as per SANS 10142-1