You need to ask yourself, can you or can't you transport electricity through a metal bolt (i.e. from one end to another)? If so, I contend that the bolt can also be considered a conductor (although not an optimal one), as well as a fastener. In addition, the fact that a bolt is an invention, which has a function and a purpose, could also make it a "device".
Whether a bolt is conductive, or not, is not the issue, IMO. Rather, is the bolt's
"principal function" conductivity, or something else? I rule out "control" as a possibility (the only other criteria necessary to meet the NEC Article 100 Definition of
Device.) I submit that a bolt's principal function is fastening.
Whereas a conductor (meaning all species of conductors or cables) is also a contrived invention, which also has a function and a purpose, could also be considered a "device".
Whether a conductor is a contrived invention with function and purpose doesn't matter when weighed against the NEC Article 100 Definition of
Device. The principal function of a Conductor, Bare, Covered or Insulated (all three NEC Article 100 defined) is to
"carry electrical energy" , hence is a Device.
IMO, the NEC uses the word 'device' in contexts which could be interpreted differently, hence the disparity of opinions put forth in this thread. I think that this definition can be over analyzed, when all we need to do is review the specific issues arising from a non-universal interpretation of the word "device" and analyze it's context and application.
This gets to the interesting thing about the turn of language in the NEC. We don't use the context of the term "device", rather we use the definition, when present in Article 100. When a subsequent definition in Article 100 uses a Article 100 defined term in a definition of another term, context doesn't reign, rather the actual definition reigns.
To illustrate, look at the definition of
Connector, Pressure (Solderless) and you will see the lead is "A device. . . ." This is not an arbitrary choice of something to be understood in context, rather, "A device. . . ." removes all ambiguity by saying that a pressure connector, used as described in the definition, is, first, a
Device.
As a result of the Article 100 Definition of Pressure Connector, a bolt used to fasten a lug to a bus, that is, a terminal (lug) to a conductor (bus), the bolt, whose principal function is to fasten, becomes a Device.
A bolt merely holding the panel to the wall, however, is not a device.
