Connectorised Penetrators
In recent decades there has been a shift towards modular platform builds to increase manufacturing flexibility. This approach sometimes calls for connectorised penetrators.
If the connectorisation is inside the hull, it can make maintenance and replacement very much easier and cheaper but operational preference is to have the connectors external to the pressure hull.

Regardless, the reliability of the harness is dependent on the sealing of the connector to the cable as well as the effectiveness of the mating parts.
High quality thermoplastic mouldings
SMI has worked with a number of manufacturers of penetrators and connectors, optimising the performance of each by terminating cables with thermoplastic mouldings that deliver connector extended life. Mouldings can also be used to bring multiple cables to the rear of a connector in a way that traditional end bells and boots cannot.