Electrical penetrator connector

An electrical penetrator connector has a fixed coupler pin unit 1 which incorporates a pin 4 having a conductive element 6. A reciprocatable component 7 includes a housing 12 defining a bore 13 into which the pin may be inserted. Within the bore is a retractable shuttle pin 22. A chamber contains dielectric fluid. A flow path 33, 34 for the dielectric fluid is configured to move the fluid past a contact 15 in the bore 13 which is to touch the contact 6 on the pin 4. The dielectric fluid circulates round the flow path every time the pin 4 is inserted into and removed from the bore. The connector may be used underwater.