Covering cables

[dingbat]

If metal capping is being used outside of the safe zones then it needs to be earthed as it's acting as an earthed metallic covering 522-06-06

No, no, no, no no! (and no again)

If you actually read 522-06-06 (soon to become 522.6.6) one of the protective measures for concealed cable is the use of "an earthed metallic covering which complies with [the requirements] for a protective conductor of the circuit concerned..."

Capping is for cable management and minor mechanical protection only.
It cannot be used as the sole means of protection outside of safe zones.
It is not intended to be earthed and anybody trying to do so is just making life hard for themselves.