My Alpine Sprite caravan is a year old and kept on a caravan site in an old railway cutting secure storage area when not in use in the summer and all winter from Nov until Mar. During it's first service by a reputable caravan dealer from where it was bought, it was discovered that "vermin" had eaten through some external wiring (which goes internally from the water heater on the offside, then runs out, externally underneath the caravan and re-enters the caravan half way along the nearside). The dealer says that the problem is very unusual and probably a "one off" but I'm keen to ensure that I don't have the same problem (and expense) again. Does anyone know of a non-toxic substance that can be painted on the external wiring or a way of enclosing the wires to make them "nibble proof"?