Connectors are ingenious devices. There are proprietary connecters as well as generic ones. The proprietary connecters are used in instances where only specific connections can be made to specific sockets. For example, an iPad has a proprietary connector to it from the cradle to the computer. The computer end is a generic USB connector but the one that engages the iPad is proprietary. This is a safety issue as well as a performance issue. The designers do not want any connecters coming into contact with the iPad that may spoil it.
Most proprietary connectors serve a singular purpose and is used to protect the device as well as a form of barrier to entry to protect their intellectual property. The connectors serve as a way to link two systems together for any number of purposes. It is possible to connect a speaker to an amplifier via a connector. It is also possible to connect a server rack to another rack using connectors. Anytime two nodes need to be paralleled, a connector is used. Connector technology is very specific. It needs the impulses or data that to specifically travel as though there was no interruption. For this to happen the connection must be formed and in full contact. It is possible that if the connection was loose and the connector was bridging a connection carrying electrons, it is possible that electrons could accumulate then jump forming an arc and an overload. This is when a loose connection causes arc faulting.
Arc-faulting is when connectors are worn and loose and the two points do not make full contact but intermittent contact. The arcing can generate tremendous heat, just as an arc welder does.