ECN Forum Forums General Topics of the Trade General Discussion Area Saltwater fish tank, help with current leak

An insulation test is done with an insulation tester,

I take it that you are not an electrician, because electrical codes have mandatory insulation testing on electrical cables and new or repaired electrical appliances.

It is basically a instrument which supplies a dc test voltage ( 250, 500 OR 1000 VOLTS ) at low capacity and will give a reading in ohms, ( kilo, mega or giga ohms ) so you can determine how good the insulation of a cable or appliance is with respect to earth, or cores in a multicore cable.

I take my masters the beginning of next yr. and Its not mandatory in MI cause I passed my J mans and am studying gor the masters and have never heard if it.

The easiest fix is to put a 3 wire cord on it with an EGC connected to any metal parts. While you have it open examine the whole thing for a manufacturing screw up that is causing your "leak".

Sorry Trick but Rodalco is right.

Lets put it this way. If I understand you right you have two heaters at 250 watts / 480 volts so they will draw current of aprox 0.5amp each.

Now this may not appear to be much but if you can feel electricity you must be drawing 10mA or more to feel it. It only takes 50mA to stop your heart beating.
Voltage, it takes 50 volts to overcome the resitance of your skin and you are stepping up the Electromotive Force up to 480v so now the 0.5amps isnt looking so inocent now.

When I think back to my school days (1970s) I used to breed tropical fish. Fresh water but never had this problem. However we used to connect the heaters pumps etc to 5amp connector strip so I was you I would go over my setup with a fine toothcombe untill I found the fault.

Try using a volt meter tie one end to ground and dip the other end in the water see if you get reading. Then switch off pumps, heaters lights one at time till the voltage is gone.
Then you will know which item is faulty.

Just out of curiosity where is the fishtank located what type of floor is it standing on?

The fish tank is on carpet with wood floor underneath... and its not 2 250w heaters its 2 250w metal halides.

It doesn't happen all the time.

And I can tell you this I have been in over a dozen fish stores, and I use to test with my fingers if there was current. You could feel current in almost all the stores if you had a small cut on your finger...

but I'll check the fixture... it only happened when there was alot of water splashing around.. and it was with 1 hand in the tank and the other on the fixture.

[This message has been edited by Trick440 (edited 10-03-2006).]

Well Trick, if GFCIs can't be used, I would want to know how much current was flowing through my grounding electrode. Do whatever you can to minimize the leakage. Quantify it, then put it through a pick up coil, sensitive relay, or other means to sense an increase beyond a safe value. If you can't trip it, alarm it. Think of how much it would cost those fish to replace you if you got juiced. Plus, it would probably place an insurmountable guilt trip on the eels.
joe

Your experience sounds dangerous and familiar. I've experienced similar shocks and found that metal housing on the light fixture was not properly grounded. Once grounded, the shock hazard disappeared.

I think one reason you have not been electrocuted when you test the system by dipping your hand in the water while touching the light fixture may be that the water in the tank is not grounded and all you feel is a slight tingle. If the water were grounded, the situation could be more serious.

My brother is a salt tank guru and he said be careful your sump isn't faulted. He seems to think it is more likely the current is coming from somewhere like that, charging the water and seeking ground through the fixture housing.

But the best way tell is to stick a probe of your tester in the water, and a probe on the frame and turn things off until it goes away.

[This message has been edited by Jps1006 (edited 10-04-2006).]

That didn't fix the problem...it only hid it.
Don

Don, that is true of everything that is grounded and trips a GFCI. You are making it safer but only by heating up the ground wire.
At a certain point the breaker trips and you have to fix it anyway. I will include refrigerators and sump pumps in this category. We know the GFCI trip is a bad thing for the food (or flooded basement) but it is still indicating a real ground fault.