Ya, most jurisdictions want the fire-rated jacket in the walls. In my area (Northern California) I haven't come across an AHJ who gave a rat's patoot about speaker wire rating.

Call your local permitting office and ask to speak to an inspector - they will tell ya. Good Luck!

You'll find that using conventional speaker wire isn't a good idea when running wires through walls because the insulation on most speaker wire will break down over time. CL2 and CL3 wire is easier to pull, and has 2 layers of insulation that mitigate against breakdown over time.

I think you may required.

Tigerninety, I'm also in Montgomery County and facing the same issue. Did you discover any rules/guidelines?

I use 14 ga building wire; do you think that might be a problem in some jurisdictions?

The quickest way to find out is call the building permit office for the city or county where you live.

Note, on the last question, if it's not specifically addressed in the codes, things like this are often at the discretion of the inspector. Of course if the office tells you it's OK and you document that (write down a name and date) and the inspector rejects it, you can explain that you asked first.

Most jurisdictions follow the National Electric Code on this. CL2/CL3 is required to prevent propagation of fire throughout the wall, non rated wire will act as a wick and spread fire.