Article 285 III tells you where you can put these TVSS. It totally depends on the type, that is, is it a type 1, 2 or 3? Type 1 supply side of service, Type 2 load side of service, Type 3 Load side of branch circuit conductors. And the connection point in type 1 or 2 would have to be UL rated for the actual termination point connection for that size and type of conductor.