Will bare copper wire corrode in water?


Old 11-13-13, 01:17 AM
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Will bare copper wire corrode in water?

I have a small electrical circuit that measures water level in a tank. The circuit is powered by 12V battery and it uses 4 wires which are positioned at 4 different levels inside the water tank, (empty, quarter full, half full, three quarters full and completely full).

I am using spare cat5 networking cable which I have lying around. It has eight strands of wire 2 stands will be used to power the circuit and 4 will be used for measuring water level. Each wire is a single strand of copper (24AWG).

I am just wondering if the exposed copper wire in water is a good idea. I know that copper does not rust, but I am just wondering if it will last or would I be better off using a stainless steel tip at the end of the wire.
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Old 11-13-13, 04:00 AM
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It depends on what the liquid is and what it contains, mineral wise. Copper will oxidize and over time will cause your readings to go whacky. Keeping them clean could insure good readings. of course you could use a waterproof proximity switch to do the same thing without the exposure to the elements, but I don't know what your plan is.
Old 11-14-13, 10:23 AM
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The tank contains just plain tap water. I don't know how a proximity switch, could be used to read different levels of water in the tank on the other hand, the water level circuit is simple and I got it cheap, so I am going ahead with it.

I plan to insert a PVC pipe in the water tank. The bottom endof the pipe will be sealed, the top end will be open. It will be weighed down with a brass weight so that it doesn't float to the top. The wire will be inserted from the top and will make contact with the water through four small pinholes at various levels. The pinholes will be sealed with silicone so that only the electrode is in contact with the water.

If copper oxidizes, then I plan to use stainless steel tips soldered to the copper electrode, so that only the stainless steel tip makes contact with the water.

Will this work for the long term?
Old 11-14-13, 06:53 PM
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Since copper does oxidize you should plan to use stainless steel tips soldered to the copper electrode.
Old 11-14-13, 07:00 PM
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Water is a very poor conductive. Tap water may not have enough impurities to conduct electricity.

Last edited by ray2047; 11-15-13 at 08:45 AM.
Old 11-15-13, 08:31 AM
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Oxidized copper(tarnish) is still a good conductor. Perhaps even better than stainless, which is a poor conductor.

Silver is the best conductor and silver tarnish is almost as good. Perhaps you could tin the copper with silver solder.

Last edited by Glennsparky; 11-15-13 at 08:54 AM.

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