2002 NEC 230.94 exception No. 2 allows "high impedance shunt circuits" to be connected directly ahead of the main. Would a TVSS unit be considered a "high impedance shunt circuit"?
No. If it is installed ahead of the service disconnect, it is called a surge protector covered by artcle 285 I think, do not have code book handy. Somebody correct me if I am wrong about the article reference
