The invention provides a method of forming a seal (62) between and around conductors (12A, 12B and 12C) of an electrical power cable (10), and has particular application as a safety measure in potentially explosive applications. The method includes passing the conductors (12A, 12B and 12C) through an opening in a body (26) so as to define a cavity within the body (26) between and around the conductors (12A, 12B and 12C); introducing an absorbent material (64) into the cavity; introducing a liquid settable material (66) into the cavity; and allowing the settable material (66) to be absorbed by the absorbent material (64) and to set thereby to seal the cavity between and around the conductors (12A, 12B and 12C).