Electrical connectors tend to have two components.

Power

Standard power connectors are from the XT series (XT30, XT60, XT90). The number signifies the rated voltage.

Power should ALWAYS be supplied from the female connector (socket).

XT series connectors should be made water resistant when in use externally

Forbidden Adapters

Plug-to-plug and socket-to-socket adapters are dangerous and should NOT be created.

If a circumstance requires a forbidden adapter, such adapters should be labeled as dangerous.