Not good: Salt water has turned the copper cable into green powder. There is certainly no current flowing here.
They work behind the scenes and can cause annoyance: cables. If they are not in order, there is even a risk of fire on board. The overview in PDF download
The on-board electrical system on most ships could probably be described as an overgrown structure. This and that is added and there is always some kind of jamming going on. Cable cross-sections? Connections? Well, it'll be fine. That can lead to problems.
This is because copper cables are by no means resistant to ageing. And if their cross-section decreases with age, the resistance increases - as does the temperature, which can ultimately even lead to a fire, as this process is not stopped by the circuit fuse, which is designed for the original cross-section of the cable.
