I have an overhead tank, on about 50 feet rooftop. I want to construct a water level gauge showing 5 levels. The circuit should work on 220v/50Hz AC. I think, we need a six core cable up to the top of the tank from the ground.
Try not using 220V/50Hz inside or anywhere near the water tank :shock:.
Using 6 core cable is not necessary and too expensive unless you got some cable for nothing. You can have a gauge with just two wires ( like the automotive fuel tank gauges- try car wreckers)
Or you can use a gauge that uses no wire at all (pneumatic)
Klaus