I have been getting interested in Rope Water Sensors which can detect when any part of the rope is wet and then using an Arduino to process that and generate an alert. Good for server rooms or anywhere you do not want water.
These things are made (or sold) by a lot of companies but they all include the electronics.
A quick google will show you what I mean
http://www.google.com/search?q=Rope Water Sensor
I am interested in just the cable - anyone know who makes this cable and sells it online?
I am in New Zealand but it could be imported i assume?