A gas-insulated cable having a plurality of lengths connected end to end, each length containing three conductors with the ends of the conductors of a length having respective metal endpieces engaging in respective cylindrical terminal metal portions of the corresponding conductors of the adjacent length, the terminal portions being provided with respective internal contacts co-operating with the endpieces, wherein a respective insulating sleeve of length substantially equal to twice its diameter is disposed around each of the endpieces and between the endpiece and the inside wall of the terminal portion.