Background:

The power transfer conduits are similar in nature to the magnetic constrictors of the warp core, in that they are ducts designed to use high-energy magnetic fields to carry energetic plasma from one point to another. But where the magnetic constrictors operate only across relatively short distances and require a very high degree of precision with a comparatively low energy plasma, the PTC's must carry very energetic plasma across large distances with - relatively speaking - far less finesse.

Federation starships are equipped with a separate PTC line for each nacelle, a measure that increases resistance to battle damage or other failures. Since most Starships have twin nacelles, two PTC's will typically be arranged to be symmetrical about the ship's centerline. These will proceed through the bulk of the engineering hull and along the connecting struts, if any, to the nacelles themselves.

Smaller versions of these heavy-duty systems are also used to carry power to components such as the phasers, shields, and high-energy scientific laboratories.