A:Answer In the past, I installed home theatre systems for Best Buy. This wire is not "rated" for in wall use. All in wall qualified "CL" rated speaker wiring has a thicker sleeve (protective coating) inside the exterior protective coating (normally white in color) as well. The primary use of the additional protection is to prevent interference from electrical wiring. When running speaker wire in the wall, at some point it will always come near or cross with electrical wiring which can cause static or interference in the sound that emits from the speakers. In bad cases, you will hear a buzz or tone at times during quiet parts of movies, games, or shows.