For several years and in several jurisdictions we have been installing residential hot tubs on decks as follows (all have passed inspections):
6-3 RX thru the house to a panel mounted on the exterior wall (as per 680-25c Ex3). From that point it's piped with the insulated ground.
Last week one of the jurisdictions (where we had never installed one) said that under 680-25d the tub contained a panel board and needed the insulated ground all the way back to the main service (i.e. pipe the whole thing). We maintained that the tub is a factory sealed and approved unit and 680-25c Ex3 could be applied. Well it wasn't worth the fight so we did it his way but the customer paid a premium. What's your opinion?