Stray Voltage

[2ras]

FYI,

Once the skin is pierced, It only takes a few tens of mA to kill a person.
The skin resistance may vary from 1000 ohms for wet skin to over 500,000 ohms for dry skin.
However, once the skin is broken through, the body presents no more than 500 ohms resistance to the current.

So be careful when measuring with any open wounds in the water.

(from someone else who works with electrical circuits...)

Ray

 

[dugg]

Funny you would bring that up lol. I had noticed that on one hand that has a cut on it, the shock is far more noticeable. On my other hand with no cuts, i barely feel it if at all. I thought that was the salt hitting the cut.

 

[dugg]

Ok, ground probe installed. I took a reading using the outlet as a ground before and after installing the probe. The before reading was 36 .45 volts, and the reading after installing the probe is now 0.31 volts. I would say it was a good investment, we will see if i get any difference in the reef, or just piece of mind. Piece of mind is enough for me, $16.99 versus death by electrocution, you do the math .

 

[Radcat]

Sounds like a good investment.

 

[eddybabyhd]

but isnt acrylic inert? Isnt it a very very poor conductor? how would the current get into the stand?

 

[Russ Braaten]

"The before reading was 36 .45 volts, and the reading after installing the probe is now 0.31 volts. "

Dugg

That is because all the voltage is running through the ground. You have completed a circuit through your fishies. Lucky, right now you don't really have a stray voltage problem but if your pump or heater were to have a voltage leak into the tank it will glow without the lights on.

 

[eddybabyhd]

thats what i am wondering, how can current cause any harm by itself. I would see if you added a ground causing more problems. That is completing the circuit as trav said.

Electricians chime in here anytime, as i am confused on the science part of this

 

[dugg]

Here is a good reason for grounding your tank if the shock don't bother you. Fish have a sensory organ called the lateral line complex. With this organ the fish can detect pressure changes in the immediate vicinity, from the movement of currents or from other fish. It is also used for navigation, finding food and avoiding predators. In most fish this lateral line complex can also detect or sense electrical charges in the water. If you have any stray voltage in the water it can overwhelm this organ, much like living in a deafening noise environment. This will cause stress, and among other things, suppress the immune system making your fish more venerable to natural bacteria and parasites which occur in every tank.

 

[eddybabyhd]

thats my point, how can the animals be affected by this current if they are not grounded

 

[dugg]

Another thing to consider is, almost all of the electrical equipment is in the sump, so the probe is taking all of the current out from the sump, and preventing it from ever reaching the display and the fish.

 

[Russ Braaten]

Gugg, you are not listening and your theory is totally wrong. Current is the movement of electrons. It is not like you remove them and make them safe. The grounding actually CAUSES the electricity. Reread the thread where others write and ignore your responses. Then you will get a basic understanding of how electricity works.

Sorry for sounding tough but you are pushing and ignoring what people are telling you. Some of us may even have an elecrtical education.

 

[poke75]

could it be that it is the extra charge (all the little extra electrons in the water) that the critters are not used to? In the wild, they are at the same potential as the earth. In our tanks they are at whatever potential (charge) that we make it with our pumps, heaters and such.

The ground probe is designed to keep the potential the same as where the critters would prefer to be (the ocean).

You are correct that if there were current flow through the fish themselves that they would die quickly (I assume, I have never tried this). I also assume that the water is a better conductor than is a critter.

These are just my thoughts, keep it going, this is kinda fun.

 

[SoonerFan732]

When you add a ground probe to the tank you ensure that you have a current flowing through your saltwater (conductor) if there is a potential difference between something in the tank the ground probe. Of course you will read a very small potential because the saltwater is now grounded when using the probe, but it doesn't stop current from flowing through the water but rather completes the path for current. As long as you don't complete a path to ground there is no current flow.

You should measure the current flowing through that grounding probe to see how much current you are drawing through your fish tank now

 

[Russ Braaten]

No, Steve, It doesn't work quite like that. Hahaha

SoonerFan, maybe we should bring some wire, a rubber mat and an electrical fence transformer to a meeting and do some electrical education. heehaw!

 

[poke75]

Teach me Russ,

What kind of charge is present in ocean water?

How many free electrons are floating around down there in a given amount of water?

Is the ground probe just to protect us two legged critters from ourselves?

 

[poke75]

Just had a brain fart in the shower,

How bout this, AC -Alternating current- Charging the tank water and discharging the tank water every .01666667 seconds.
Does that mean there should be however much current flow in that amount of time or untill the water is fully charged to its capacatance?

If it were DC, the voltage might not bother them, but since it is AC?

 

[poke75]

After reading that, I will try and reword it tomorrow when I am rested and things are clearer in my foggy mind.

Just had a mid term test tonight.

 

[poke75]

Lets see if this sounds better.

The voltage we introduce is AC, so doesn't the current come in and go out at 60 Hz?

So, does it help to place a ground probe in there?

I would think Possibly- IF: the current flows easier through the water than it does a critter.

Instead of charging and discharging the water 60 times a second, the current should flow from the faulty equipment, around all the higher resistance critters and into the ground probe.

It would be interesting to test this.

Steve

 

[chris4693]

I still think there is no potential difference in the water so the fish would feel nothing, unless you took a straight AC wire and used a aligator clip to attach it to your fishes tail creating a difference it would feel.

The REAL problem is faulty equipment, or equipment with faulty wireing.

If any current is present the the flow of electrons would be the least resistant path. (Water in this case)

 

[Matrexz]

If this is the case why do so many people talk about grounding probes being necessary to help prevent lateral line problems for the fish????