I wish to place 2 inch diameter low voltage lights in a coffered ceiling I am finishing up.  I know that all 120 volt wiring must terminate in an electrical box if there is a wire connection or termination.  Is that also the case with 12 volt wiring if the transformer is installed in the living space?  If I punch 2 inch diameter holes in the ceiling drywall and install the lights using the friction fit provisions of the lights, then there will have to be wiring spices in the attic between joists.  Is this allowable?

Thanks much

Dennis