Grounding my light controller box

Hey,

So my friend that has alot of experience with light boxes told me not worry about grounding the box from the marked ground point, just plug in the timer cable and that will be enough to ground the box.

The controller has not been plumbed into power yet but I thought I'd get some second opinions.
Based in Australia on 240v.

Do you have a continuity tester ? If so test from the earth lug to the earth pin on the box powerpoint . This will confirm if the box is connected internally .
And secondly theres no guarantee that the power point in your house has an earth at it.
And being that i know what that box is you should run a 6mm earth wire to it from the main earthing system if theres a fault the earth in the flex cable isnt heavy enough or at least a 4mm earth. The lug is there for a reason.
Plus if you remove the plug from the wall disconnecting the "earth" the power is still on an unearthed box