[Al Skierkiewicz]

Jason,
It really depends on the speaker wire but what is of prime importance is the ability of the insulation to withstand voltage breakdown. Most wire is capable of withstanding 300 volts which we never achieve. Speaker wire is generally unrated but typical home systems running 100 watts per channel can easily peak over 80 volts P-P so the wire is able to handle that. Building inspectors following most electrical codes expect/demand that any wiring over 25 volts must be in conduit. It is for this reason, that PA amplifiers have a 25 volt output as well as a 70.7 volt output. It doesn't change the fact that higher voltages are present, but make the inspector happy. In many states, conduit is not required in residential installations. Minnesota is one of these and the wire used is a dual insulation type.