Joe, the possible problem with behind-the-wall speaker cables and interconnects isn't that they might start a fire, but that if there was a fire that reached them, the PVC(polyvinyl chloride)standard jacket material would burn and release dangerous fumes. Codes vary between the U.S. and Canada and local interpretations also differ as to what's required, but various jacket materials which prevent or at least delay the noxious fumes are available.

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Enjoy the music, not the equipment.