Defining the Terms
Bonding Conductor or jumper: A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.
Bonding Jumper, Main: The connection between the grounded circuit conductor and the equipment grounding conductor, or the supply-side bonding jumper, or both, at the service.
Bonding jumper, supply side: A conductor installed on the supply side of a service or within a service equipment enclosure(s), or for a separately derived system, that ensures the required electrical conductivity between metal parts required to be electrically connected.
Bonding jumper, system: The connection between the grounded circuit conductor and the supply-side bounding jumper, or the equipment grounding conductor, or both, at a separately derived system.
Ground: The earth.
Ground Fault Current Path: An electrically conductive path from the point of a ground fault on a wiring system through normally non-current-carrying conductors, grounded conductors, equipment, or the earth to the electrical supply source.
Grounding Conductor, Equipment (EGC): A conductive path(s) that is part of an effective ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both.
Grounding Electrode: A conducting object through which a direct connection to earth is established. Examples: Water Pipe, Metal in-ground support structure, ground rod, etc. found in 250.52(A)
Separately Derived System: An electrical source, other than a service, having no direct connection(s) to circuit conductors of any other electrical source other than those established by grounding and bonding connections.
Service: The conductors and equipment connecting the serving utility to the wiring system of the premises served.
Service Equipment: The necessary equipment, consisting of a circuit breaker(s) or switch(es) and fuse(s) and their accessories, connected to the serving utility and intended to constitute the main control and disconnect of the serving utility.
Three Pole Transfer Switches: Has the means to switch 3 items. See the end note.
Four Pole Transfer Switches: Has the means to switch 4 items. See the end note.
Power Inlet: Comparable to a Trystar docking station
End Note: Four pole vs Three pole is not great terminology because if one is talking about putting in a single phase 120/240-volt separately derived system, they would use a Three Pole Transfer switch. A Four Pole Switching device would give them a separately derived system for a 120/208-volt three phase separately derived system.