Stray Voltage

[Zakk]

Crap, tested the tank today for the first time for stray voltage.  The multimeter is reading about a 7V with everything turned on(!).  There's no one culprit, each pump in turn added a little bit more current to the water. 

Anyplace in town sell good grounding probes?  I'm going to DIY something now (this might explain my upset leather), but I'd like to get a good probe, probably titanium.

I had no idea these things leaked current!

Secondly, does anyone know if GFO removes silicates?

 

[Darryl_V]

Im not a believer in grounding probes in an aquarium for the health of livestock.  A grounding probe will allow current to travel.  Its not a bad idea to couple a grounding probe with a GFI for human safety though.  Although I just rely on a GFI only and recommend everyone have at least a GFI.

The voltage you are finding is induced from the magnetic field from the pumps etc.  Unless you start seeing higher voltage which would indicate a short in some equipment, I wouldnt worry about it.  Make sure you have a GFI for personal safety and IMO the stray voltage you are seeing is not a problem.

 

[Zakk]

Im not a believer in grounding probes in an aquarium for the health of livestock.  A grounding probe will allow current to travel.  Its not a bad idea to couple a grounding probe with a GFI for human safety though.  Although I just rely on a GFI only and recommend everyone have at least a GFI.

The voltage you are finding is induced from the magnetic field from the pumps etc.  Unless you start seeing higher voltage which would indicate a short in some equipment, I wouldnt worry about it.  Make sure you have a GFI for personal safety and IMO the stray voltage you are seeing is not a problem.

Ah, okay, good to know.  Yes, the first thing I installed on the main plug for the tank was a CGFI outlet, and I test it once in a while.  An extention cord dropped in the sump once and I can say firsthand that the GFI worked instantly.  (I used to have a renovation company, I'm familiar with the dangers of electricity)  ;D

So 6V isn't really an issue? 

 

[shayneh]

Just a quick note voltage doesn't kill... it's the amperage you need to worry about. I had a friend thrown about 10feet by accidentally touching a live 6V lead on a robotic welder arm we were working on. It's funny now since he was a bit shaken but ok. A GFI is the minimum precaution we should all take to prevent any stray electricity from returning to it's maker and taking us with it.

This is just miscellaneous rambling now but does anyone know how leaking current knows where it came from and why it wouldn't just try to return to the nearest electrical generating station as opposed to it's original source?? 

 

[Darryl_V]

This is just miscellaneous rambling now but does anyone know how leaking current knows where it came from and why it wouldn't just try to return to the nearest electrical generating station as opposed to it's original source??

Hmmmm....this question doesn't make a whole lot of sense but I will give it a go.  Leaking current does not have a consciousness....so it doesn't know where it came from?  Sorry maybe I don't understand that question.

It doesn't return to "the nearest electrical generating station" because electricity takes the path of least resistance (or no path if none exists)....most likely ground.  BUT in the case of magnetically induced voltage from pumps....well it didn't even come from the generating station to begin with.

 

[Zakk]

So with a grounding probe, voltage in the tank is 0, without one, voltage is 7V.    I would think that an easy path to ground would take away all the stray voltage and make the corals happy.  Without that, it is a small amount of current always looking for a ground, no? 

I want to order a titanium ground, but of course want what's best for the tank...which is the best route, to ground or not to ground?

 

[Darryl_V]

Have you ever seen birds on high voltage lines......... unharmed.

Now add a ground to that line and you got dead birds.

Best analogy I could come up with.

BTW..... with all the pumps and such I have 27v in my sump.  Tank is doing great.

 

[shayneh]

Only flaw in that analogy is that in this scenario the potential ground is the unsuspecting aquarist that just put their hand in the tank.....and the birds/fish are still potentially fried like the ground/aquarist. LOL!

Another wrench to throw in the works is to point out that GCFI's can fail (I have replaced 2 myself in the last 5 years). I forget how many milliamps they trip at but I know it doesn't take very many more running from an arm in the tank across the chest/heart through to the floor to prove fatal or mess up the hearts electrical impulses.

 

[shayneh]

With magnetic fields created with powerheads/pumps in the water there will likely always be determinable readings but my biggest scenarios are the electrical coatings failing on the pumps altogether or a light hood bumped into the tank while mucking about. In both these instances I would gladly sacrifice my entire tanks contents as opposed to the jolt I would receive.

 

[Darryl_V]

Only flaw in that analogy is that in this scenario the potential ground is the unsuspecting aquarist that just put their hand in the tank.....and the birds/fish are still potentially fried like the ground/aquarist. LOL!

Another wrench to throw in the works is to point out that GCFI's can fail (I have replaced 2 myself in the last 5 years). I forget how many milliamps they trip at but I know it doesn't take very many more running from an arm in the tank across the chest/heart through to the floor to prove fatal or mess up the hearts electrical impulses.

You are right.  But even if you are completing the path to ground from a low resistance short, a working GFI will trip and you will not be harmed.  That is why I suggest everyone have a GFI and test it regularly.  AND for complete safety, a grounding probe is a good idea, all though not needed IF you have a proper working GFI.

BUT we are talking about the health of corals and fish....and all Im saying that these small voltages are no harm to the fish and corals.  Infact I would assume most aquariums are isolated which in case means that there is no current traveling until a path to ground is provided.

So to recap.....for safety Im saying GFI minimum, grounding probe better.  But for the aquarium inhabitants I'm saying if you have low induced voltage, they are fine without a grounding probe.  I don't know if a grounding probe would be a negative for the aquarium inhabants though, just not sure as I have never had one.

One last thing....if you have high leaking voltage or a clear short....getting rid of the problem equipment is the first step.

This is all based on my experience and opinion though...so take it for what it's worth.

 

[Zakk]

BTW..... with all the pumps and such I have 27v in my sump.  Tank is doing great.

Heh can't argue with that.  ;D

 

[Krazykarl]

So I stuck my hand in my tank again today abs wouldn't you know that tingling feeling on the tip of my rhumb was there again. Unplugged every thing one at a time but still felt it. It doesn't make sense to me. Anyone wanna help?

 

[phi delt reefer]

did you make sure this guy isnt in your sump?

 

[Blob-79]

lol...

dont you have a multimeter karl?

 

[Krazykarl]

Ya but if you could see my workshop lol. You'd understand... I can't find anything....lol.