dhindry Posted July 9, 2005 Report Share Posted July 9, 2005 Uh oh whats gone wrong??? Being electrically concious of all my salt water and power I check all my electrical equipment in the tank weekly. Using my multimeter I measure the potential difference between the tank water and earth. Up untill yesterday it was below 1volt AC. I added rowaphos yesterday which is as I understand an Iron based product. As I am using a fluadized filter a little leaked into the tank causing the tank to go cloudy and a little orange. This evening I put my hand in the sump to move somthing and put my other hand on the stainless steel sink next to it. An Electric shock was the result. I measured the potential difference between the the tank and earth and it is now approx 60 volts AC!!!! The next step was to remove each electrical device one at a time to see what was the cause Each device is only contributing approx 11volts each. More so for the pumps. So I can't blame just one device for doing this. My thoughts are now.... Is the iron in the rowaphos that is suspended in the tank acting like a transformer around the AC devices inturn causing ac current to flow???? Has anyone else have this happen to them? Will earthing the tank/sump stop this problem???? Thanks Daniel Quote Link to comment Share on other sites More sharing options...
chimera Posted July 9, 2005 Report Share Posted July 9, 2005 that'd be one for layton to answer i think! Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 Interesting. Don't know if i'll be too much help. I'd say it is unlikely that the iron is acting as a transformer. You would still need another coil to complete the magnetic circuit, I would have thought your hand is unlikely to have a high enough inductance. Also the permeability of the water would be low. So more than likely it is some sort of leakage current. Grounding will help, of course it seems unusual that the problem starts after adding rowa. But i can't see any reason why rowa would cause this. Anyone have any ideas? Leakage current is usually caused by faulty equipment, which has not necessarily failed. Heaters which have a little water in them, pumps where water has seeped thorough a crack in the epoxy potting. Layton Quote Link to comment Share on other sites More sharing options...
Fay Posted July 9, 2005 Report Share Posted July 9, 2005 Yep had a nice big shocking experience when I had a faulty heater in the sump put my hand up to adjust the light on the wall over the sump to see what I was doing and wam!!!!!!!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 9, 2005 Author Report Share Posted July 9, 2005 Adding a grounding probe might not work in this situation. I would think it would trip the rcd's I have as the fault current is now running straight to ground. At the moment say the tank is sitting at a potential of approx 70volts. Everything in the tank is at this potential. Adding a ground probe would then take this current away but everything in the current path now becomes a conductor. I would have thought this would cause damage to any fish that swam between the leaking device and the ground probe. Daniel Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 It is possible that adding a grounding probe will trip the RCD. What type of power heads and pumps are you using, any air pumps? Any sign of condensation or water in your heater? I would try and isolate what is causing the problem. But a grounding probe will at least stop the electric shocks. Layton Quote Link to comment Share on other sites More sharing options...
Kermit Posted July 9, 2005 Report Share Posted July 9, 2005 Hmm you want to check what your current is to as current is the killer not voltage. Layton you might know off the top of your head, whats the level of voltage were it penetraites the skin i have a figure of 50 volts, but this may not apply in water as humidity effects the value and being in water. Robert Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 9, 2005 Author Report Share Posted July 9, 2005 This is only happening in my sump. Current doesn't seem to make it back to the main tank. In the sump there are two heaters, both look fine, no condensation that I can see. One small powerhead attached to the skimmer as this sits in the sump. And one laguna UP6 as the return pump. When I turn all the devices off at the wall, the voltage dissapears. If I have everything running and then unplug one at a time, I can't Identify which one is the culprit as they all seem to be leaking I just ran a little test and grounded the tank via a 100k resistor. This dropped the voltage in the tank to around 30 volts AC. I think my voltmeter may have a via high impedence. But this still shows that their is a voltage there. There has to be a current as I felt it when I touched it. Quote Link to comment Share on other sites More sharing options...
Kermit Posted July 9, 2005 Report Share Posted July 9, 2005 That calculates to 0.3mA of current through the rersistor your RCD will be rated at either 10 or 30 mA more likely 30mA for domestic unless you have an operating theatre and do open wound surgery . What does the voltage and current do for each individual device in the sump? Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 Try gounding the tank through the multimeter and the resistor (in series) with the multimeter set to AC current. What reading do you get? 100mA is considered the leathal current. Of course it is possible that the pumps and heaters are all leaking current. Try physically removing the heaters from the sump and see if the problem is still there. What type of pump is connected to the skimmer? Layton Quote Link to comment Share on other sites More sharing options...
Alan Posted July 9, 2005 Report Share Posted July 9, 2005 A bird can sit on a 24000 volt line and sing happily. Alan 104 Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 9, 2005 Author Report Share Posted July 9, 2005 I have just found this item http://avdil.gtri.gatech.edu/RCM/RCM/Aquarium/GroundingProbes.html It explains some interesting things to consider. Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 ...until it touches the other line :lol: The voltage is not the problem. It's the current that flows when you put your hand in. It is also a sign of pending equipment failure, which can have other consequences for the tank. Layton Quote Link to comment Share on other sites More sharing options...
Faran Posted July 9, 2005 Report Share Posted July 9, 2005 Yeah; of course, it's not grounded. But if a possum accidentally touches two of those same 24000volt lines at the same time... well, I'm sure you've seen a line-BBQed possum at least once in your life. Not a pretty sight. Quote Link to comment Share on other sites More sharing options...
Kermit Posted July 9, 2005 Report Share Posted July 9, 2005 Yeah cos it touches two lines when a bird sitting on a line only sits on one thus not completing the circuit for current to flow. Quote Link to comment Share on other sites More sharing options...
Alan Posted July 9, 2005 Report Share Posted July 9, 2005 I saw a sparrow once that saw a bug it wanted on the other line. wooops. No feet No beak, Dead birdie. Also saw a possum do that too. Thrown done from a line contact, and as I went for my knife to scalp it, it took off. One lucky beastie, and I missed out on my 2/6d. Alan 104 Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 9, 2005 Author Report Share Posted July 9, 2005 Ok Total AC Current flowing is about 1.2mA So I have no idea why I got a belt off it yesterday. I shall keep an eye on it and see what happens over time. Thanks Daniel Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 You'll still feel it at a couple of mA, it just won't kill you. I would still try to find out what causing it it could cause major problems in the future. What brand of pump is running the skimmer? Is it a venturi skimmer? Layton Quote Link to comment Share on other sites More sharing options...
Kermit Posted July 9, 2005 Report Share Posted July 9, 2005 You'll still get a shock off of 1.2mA its just not likely to kill you. Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 9, 2005 Author Report Share Posted July 9, 2005 Skimmer pump is a no brand, it came with the skimmer but doesn't say a name on it. It doesn't matter what device is on as the current is pretty constant for each device. I would be curious to see if others have measured their tanks to see if there is any stray voltages floating around so to speak. Yes the skimmer is a venturi type. I wonder if it is more like a build up of static that bit me ?????? All the water rushing through the plastic pipes etc. Daniel Quote Link to comment Share on other sites More sharing options...
lduncan Posted July 9, 2005 Report Share Posted July 9, 2005 It's not static elec if the current flows continuously when grounded. Quote Link to comment Share on other sites More sharing options...
Ira Posted July 10, 2005 Report Share Posted July 10, 2005 My tank it seems to be more of a total of everything in the tank, not just one device. And I only really notice it if I put my hand in the tank and have a scrape or something so the current gets a bit shorter path to a nerve, I guess. Quote Link to comment Share on other sites More sharing options...
dhindry Posted July 10, 2005 Author Report Share Posted July 10, 2005 Now that you mention that Ira, the hand I had in the tank has a decent scratch on it Maybe thats why I felt it this time. Quote Link to comment Share on other sites More sharing options...
cracker Posted July 11, 2005 Report Share Posted July 11, 2005 Souns like one dodgy peice of equipment to me. You will need to individually remove each peice completely away from the tank until the current stops. I'd say one thing is leaking current. Probably from what Layton said, seepage into epoxy or similar, Could be anything submerged. Quote Link to comment Share on other sites More sharing options...
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