electric shocks!

[mat692]

I get a electric shock (only a tingle) whenever I have my hand in my sump and arm againts my metal stand my last setup this was caused by a cracked heater but this time useig a multimeter Ive tested for Voltage in the water earthed through the stand and with everything unplugged tested for power which came up with nothing and tryed testing with each individual item pluged in by them selves ---everything gave a Voltage reading , all items coming to 75V even the air pump which is only connected to the water by air hose gave a reading.

ANY IDEAS??

maybe faulty extension cord or multi boxes????

[davidb]

it could just be static from the stand. Often when I go to work in the mornings at the museum I have to touch all the metal display lids with a piece if wood or something to ground it. I don't know the science behind it as I am a biologist not a physicist but it seems to stop me getting zapped when I'm feeding the fish :lol: :lol:

[richms]

All electrical equipment will have some leakage to the chassis. Mainly stuff with switching powersupplys like dvd players, vcr's, laptop computers etc - if you measure these with a sensitive digital multimeter its not uncommon to get over 100 volts, yet you cant feel anything because the impedance between the power and the chassis is so high that not enough current flows to even feel. Heaters can capacitivly couple mains to the water quite well simply because of the amount of live metal in them seperated only by a thin piece of glass.

More of an issue is the current you will get to earth from the tank. Get an old analog meter and measure the voltage, it shouldnt show anything, then try to measure the current with a digital meter, you will probarbly find a few miliamps if you are able to feel it. Any more and you would be tripping your RCD in most cases.

If you dont have an rcd, go buy one before you stick your hand in the tank again, they are only $17 at bunnings for an arlec plugin one.