2 core + earth or 3 core + earth wire?

[Wrath of Khan]

Anyone know why a 3 core + earth has 2 earths?
I hope I haven't just bought the wrong cable but can I run a 2 core + earth surfix cable from an inverter to an isolator?

 

[Düber]

I would hazard that you have a cable for 3 phase things.

If you are using it for single phase you get to choose the earth.


/lets himself out.

 

[thehuman]

Anyone know why a 3 core + earth has 2 earths?
I hope I haven't just bought the wrong cable but can I run a 2 core + earth surfix cable from an inverter to an isolator?

Picture of cable with color codes showing please.