Ok So the light fixture on my Saltwater fishtank is leaking current.
When I touch the fixture I can feel it and I can really feel it with 1 hand in the water.
Any ideas on how to fix this problem?
They sell these ground probes which I am going to get but thats taking the current from the tank....
http://www.marinedepot.com/aquarium_miscellaneous_titanium_grounding_probe.asp?CartId= maybe I should bond the fixture? I'm sure that was done at the factory but I dont know why im getting shocked.
[This message has been edited by Trick440 (edited 10-02-2006).]
Do an insulation test on it which will give you the condition of the insulation of the wiring and the fixture.
Possible a poor termination or loose strands may touch the outer exposed metal.
Bear in mind that you have a dangerous situation at the moment and do not touch it with your hand whatsoever.
Chance of electrocution is possible.
Take it out and test it or get a new one, at the moment it is dangerous !!
Its very common to feel some shocks in saltwater. Its 'Salt' water, very conductive. So I'm not worried about the shocks to much. I just want to find a cure the common problem.
But I would do an insulation test if I knew what that was. I'm hoping to cure this with an easy bond... or is that to simple.
Play the odds...
The odds are that you are dealing with capacitive coupling to the salt water.
Your ONLY solution is to drain this EMF potential to ground.
The exact same effect can be had in hot tubs with ungrounded ( pre 1962 ) wiring. Any hot tub will build up quite a potential....
But the amps should be low....
Bleed them off through a sweet ground.
The zap will be gone.
I've worked on a few saltwater aquariums and have not been shocked. I have done work for a "fish tank cleaning guy" that probably works on 30-50 different salt aquariums a week, and I know none of them shock him.
I don't think it's safe to say that it's common to recieve a shock in saltwater. You have a problem with your equipment, find the problem and get rid of it or the equipment. Also, you should put all your saltwater equipment on GFI's. I have found faulty pumps tend to trip them out, especially the cheap pumps from overseas. Check heaters as well.
You might consider getting rid of the Electric Eels too.
Joe
Har Har that was a good one Joe.
Perhaps completely isolate it with an isolation transformer????
A.D
capacitive coupling ... I like that.
I'm gonna try the ground probe I posted and then I'm going to bond the fiture to a definate ground.
And Mhulbert... you might wanna ask your fish guy, cause theres current in saltwater fish tanks all the time. With saltwater, it damn near travels through the air.... especially when you have so many watts being pulled by these fixtures.
My setup is not very large and its 2 x 250w MH at 480v (it think it was 480) after the transformer, and then 2 more transformers powering 4- 80w t5 light.. with fans, moonlights, etc, and thats just 1 fixture.
And you also don't GFCI your pumps. A tripped GFCI could easily mean a $2500 loss in corals and fish.. and thats just a moderate setups loss.. a large setup the loss would be even greater.
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).]
I've experienced similar shocks and found that metal housing on the light fixture was not properly grounded. Once grounded, the shock hazard disappeared.
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.