Dedicated power lines-getting started

Subaruguru,
The Belden 83802 is a FPLP rated cable, power-limited fire alarm plenum cable. FPLP cables are listed in NEC 760, National Electric Code:
"Conductor and cables for power-limited fire alarm circuits shall be listed for the purpose and meet the following requirements: A. Conductors are solid or stranded copper. B. Conductors in a multiconductor cable shall not be smaller than 26 AWG. Single conductors shall not be smaller than 18 AWG. C. The voltage rating shall not be marked on the cable. Voltage ratings marked on the cables may be misinterpreted to suggest that they can be used for Class 1, electric light and power applications. ..."

That seems to infer the Belden 83803/2 is NOT approved for use in normal household AC circuits. You should check with the local electrical inspector if the NEC is adopted in your area before going any further with this and advise others to do the same.

Romex NM, the typical wire used in AC circuits, is not approved in plenums because the jacket will melt creating toxic gases when the heat from a fire moves through the ducts. The teflon insulation and jacket on the plenum cable is more resistant to the heat.
Romex NM has a max voltage rating of 600v and 83803 is rated at 300v.
JPS Labs makes in-wall wire that is 600v rated like Romex NM. It is very expensive at $18/ft., but doesn't compromise the safety and is designed for what you want to do.
Power AC In-Wall cable

Oy. I don't know how you can infer that from reading this paragraph of the code. The Belden FEP dielectric is rated to 600F, and thus extremely safe for plenum use without a conduit. Its voltage rating, even at 300v (I thought it was higher), is still comfortably above the 120 it's used for.
You can even run it at 240.
The 600v issue is moot. I have seen several professional installations of 8380x that were not at all questioned re legality or hazard. 12AWG, all Teflon and copper. What's to worry? The stuff sounds GREAT, and is a couple bucks/foot.
If you're worried about an inspector not liking the 83802's twisted shield used as a bus ground, then spend the extra 50% on the 83803. End of story. $18/ft? The only stuff that I've seen that I'd like to see that perhaps REASONABLY approaches value at this cost is doubling or tripling up on the silver-coated Teflon 16AWG stuff Belden makes for a bit over $4/ft. That'd be $9/ft wholesale for 13AWG, or $13/ft for a bit bigger than 12AWG. 83802 is 1/8th the latter, and thus most reasonable for dedicated lines. Using the silver stuff might be interesting for PCs, though, eh?

From NEC Article 760:
"... The voltage rating shall not be marked on the cable. Voltage ratings marked on the cables may be misinterpreted to suggest that they can be used for Class 1, electric light and power applications. ..."

Did you really read it?
Look at a length of NM wire, it has 600v printed on the jacket. Art. 760 says printing 300v on the jacket is prohibited because it could lead to a misinterpretation of the intended use which does not include what you are proposing to use it for, power applications.

I have a definitive answer from someone who actually knows the National Electric Code and where to look in the NEC, chapter and verse. I would be glad to forward the information to anyone interested.

Double-oy! When I added a family-room to my house here in Medford the lectrical inspector insisted that I install a duplex in EVERY wall at least 18" long, INCLUDING the one between adjoining (20" apart!) bathroom and basement doors!
There it was: chapter, verse and line. Somehow he didn't question the oh-so-bright 83802 dedicated lines streaking from the breaker box across the basement ceiling. But then the former only proves he may be wrong on the latter. Sigh....

Belden tech support replied to my email and said they recommend their FPLP cable (83802, 83803, etc.) not be used for 110v power supply, from panel to receptacle. They said it is for "Control and Instrumentation" cables for Fire Alarm and Tray applications and are not designed for 110v applications.

The assistant state electrical inspector and regional offices both said an emphatic "NO" when I asked if FPLP can be used in this manner. I have now contacted three electricians, the regional and state electrical inpectors offices, and Belden tech support. They all give the same answer.

I had hoped 83803, at least, could be approved but unless it was overlooked by the local inspector it would not be, not in my state. I was told I'd have to get it all removed at whatever phase of construction it was discovered. That could prove to be a very costly mistake.