A protective sleeve 25 has a first channel 31 in
fixed position relative to a second channel 33, each channel suitable for receiving a respective one of a pair of aircraft wiring harnesses 15a,15b to hold them apart. In use, the pair of wiring harnesses received in the channels extend between an aircraft
fixed wing (fig.2B,5), and a wing tip device (fig.2B,11) moveable between a flight configuration and a ground configuration in which the span of the wing is reduced, each harness contains conductors transmitting power and / or data to the wing tip device, such as separate high and
low voltage conductors. The sleeve is preferably formed from a single piece of a resilient fluorosilicone
polymer known as FVMQ, with circular channels either side of a 75mm thick
webbing (fig.8,18), the channel walls being at least 2mm thick. Each channel may have a slit 27,29 with closure tabs 35 extending along its underside, the sleeve may deform opening the slits for removal. The aircraft may have a pair of sleeve guides (fig.2B,19,21), respectively above and below the sleeve, to constrain sleeve movement during wing tip movement, the sleeve urged against the guides in the flight configuration.