Abstract: A telecommunications terminal block employs a housing having a number of separate dielectrically, isolated chambers disposed therein. Service wires to be connected to a splice cable are inserted into a chamber through openings in the housing and into a movable wire carrier member disposed within the chamber. An actuator member drives the carrier member from a first position, at which the wires are inserted, to a second position where the wires engage a contact element which electrically couples them to the splice cable. The carrier member moves within the chamber so as to allow, an electrically insulating medium within the chamber to flow around the carrier and maintain a constant volume of the medium within the chamber. Loss of insulating medium is thereby avoided during connection and reconnection of the service wires allowing improved protection from environmental factors such as moisture, chemicals and other contaminants.