It's also all too common for TN-S supplies to become de facto TT with an uncertain earthing arrangement due to the cable clamp on the sheath of the PILC deteriorating, or just not being fitted in the first place. Many sparks I know of won't tighten the clamp because 'it's not our responsibility and that cable is scary old'. Fair enough. I've had a few like that. I install a MET, bring all my bonding/earthing to there, then contact the DNO to replace the earth. Never had them turn me down.
It's also all too common for TN-S supplies to become de facto TT with an uncertain earthing arrangement due to the cable clamp on the sheath of the PILC deteriorating, or just not being fitted in the first place. Many sparks I know of won't tighten the clamp because 'it's not our responsibility and that cable is scary old'. Fair enough. I've had a few like that. I install a MET, bring all my bonding/earthing to there, then contact the DNO to replace the earth. Never had them turn me down.
