A question to my learned friends.

We wish to place some lights on a very long fence, the connection between lights is made using silicon cabtyre wire, to handle the elements. The lights are connected to the secondary of an isolating transformer, and the isolating transformer is connected to the DB box, does the light circuit require to have a COC?

Under the same scenario as above, the isolating transformer is swopped out to a low voltage AC transformer, what are the requirements for the secondary light circuit?