Has this been run past a 'leco? The earth should be longer/arranged as suchso if something does get pulled, the earth will still be connected which allows the circuit breaker to trip should the active touch something metal. If the earth comes off then someone touching it could well become the ground.
Thanks Wiggman - good call. While I can't see the strain relief (metal cable gland) failing, I can certainly see the merit in making it as safe as possible.
Those cable braids compromise the IP seal on the cable gland allowing liquid to enter. I would gather the braid and cable tie it up before it enters the gland - not as pretty but that's what it is.
Note that their other metal boxes have a thicker lid/walls and do not allow enough of the element thread to pass through. Note this was nearly three years ago... so the supplied stocks may have different specs.