The difference between Incommunicado and Off the grid

Incommunicado as an adjective:

In a state or condition in which one is unable or unwilling to communicate.

Incommunicado as an adverb:

In a manner in which communication with outsiders is not possible, for either voluntary or involuntary reasons, especially due to confinement or reclusiveness.

Off the grid as an adjective (of a home, business, or the occupants thereof):

Not using electricity from the public electrical supply system.

Off the grid as an adjective:

Not connected to a publicly available communication system, such as the world-wide web or a mobile telephone network.

Off the grid as an adjective (idiomatic):

Isolated; in a remote location; in seclusion; not participating in some official process or system.

Off the grid as an adverb:

In or into a situation or place in which electricity from the public electricity system is not used.

Off the grid as an adverb (idiomatic):

In or into a clandestine or isolated situation or place, especially one in which public communication is curtailed.

Off the grid as an adverb (idiomatic):

Secretly; in a clandestine manner.