How to explain why No Grounding allowed??

[brother]

A question was asked about low voltage lighting, where it forbids 'Grounding of secondary circuits'. I could not really give an explanation other than just speculating, because its not too often you see the NEC forbid grounding. Does anyone know why low voltage lighting is forbidden to have grounding?

 

[Greentagger]

250.22(4) references us to 411.6(A) which it appears they are talking about bonding the neutral or grounded conductor of the transformer? It says the secondary to be separated from branch circuit through an isolation transformer. I don’t believethe intent is not to say you cannot ground or run an EGC to those lights but not to ground secondary of these transformers? Also included in 250.22(5) is secondary circuits referenced in low voltage pool lights where it references not bonding secondary of these transformers. You are required to run an EGC to these if it is required.