The power transfer quality is a big deal for the efficiency. However, the connector would be effected under humid enviorment. Meanwhile, you would need the waterproof connector.
The waterproof connector is improved due to the developement of technology. The wires not only could be assemble on the land, it might even be barried under the sea; then the waterproof connector becomes more important in this situation.
The power transfer rate could be effected in many ways, but most time it's due to the wire and waterproof connector. If you have paid so much for the precious and valuable equipments, just take the little parts like waterproof connector as important as other instrument. That will surely reduce the time and money for maintenance.