A connection adapter has electrical contacts for connection to a corresponding mating contact of a terminal. The mating contacts are received in terminal domes formed from an insulating material which is configured such that the mating contacts are accessible to a contact of the connection adapter through a contact guide opening in a terminal dome. Connection adapter guides in the terminal domes are configured to interact with terminal guides to guide the connection adapter from a placement position, where it is placed onto the terminal in the correct position where the connection adapter and terminal can be fitted together, to detent position, where the connection adapter is placed and held on the terminal so that the electrical contacts of the connection adapter and the mating contacts of the terminal can be moved relative to each other to establish electrical contact.