It all depends on the cable type. BMS 13-13 (used in 707/720, amonst others) could crack lengthwise.
BMS 13-51 and other thin-walled cables can also lose the outer coating without losing the integrity of the inner insulator (which is copper coloured - the uninitiated are unaware that most aircraft cable is nickel plated copper).
The inherent risks associated with Kapton are well known.
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Bus429 - the pilot's pal!