Abstract: The assembly comprises an insulating housing having concentric arrays of terminal receiving cavities extending between a rear face and a front face of the housing. Terminal latching lances extends from an intermediate face of the housing between the front and rear faces. Each cavity is in the form of an open channel between the intermediate face and the front face. The channels of one array of cavities open towards the channels of the other array of cavities and vice versa. A terminal locking insulating insert is insertable into the housing to maintain the latching lances in locking engagement with terminals and to complete the channels so that each cavity is tubular throughout.