Abstract: The long term water intrusion resistance of cable splice systems that use a gelable encapsulant that is pressurized prior to geletion can be improved by providing pressurization means that maintain the pressure on the cured encapsulant above a given pressure p.sub.2 >p.sub.o, where p.sub.o is the ambient pressure. Absent such pressurization means, the pressure on the encapsulant typically decreases with time due to creep or relaxation of nominally rigid components, e.g., a polymeric closure around the encapsulated splice, or varies due to differential thermal contraction. The pressurization means comprises one or more energy storage elements, e.g., an elastic member such as a spring, or a volume of compressed gas.