Wiring advice/help needed (voltage in tank)

[Wildechild_01]

Originally Posted by Vancity

So im getting the feeling that the grounding probe does absolutely nothing to protect the fish corals and other tank inhabitants from harm, it only prevents me from getting zapped (to a certain extent).

By George I think he's got it. Based on my personal results so far the article in the next quote i say put the ground probe in... extra safe for you, minimal extra risk to tank inhabitants.

Originally Posted by Vancity

Just had a read through this, Voltage in the aquarium it was at the bottom of the page that Wildechild posted.
Something I found very interesting (as my head almost exploded from technicalities) was the part about bizarre powerhead measurements half way down the page. The plastic housing of his powerhead induces voltage, this has nothing to from what I can tell that there's anything physically or visually wrong with pump or wiring (well maybe internally) but nothing noted. It appears to be the same phenomenon that has been taking place with all my equipment. Sure, I can check the new'ish skimmer for signs of issues, but highly doubt I will find anything visibly wrong, therefore the pump of the skimmer is now leaking voltage by way of "some cause".

Find the answer and I'll call you genius! Or a good Googler

Yeah that is a bit of a brain melter of an article, but good.

The question with the power heads is a result of magnetic induction...

When the powerhead impeller spins or the impeller in your skimmer or return pump spins it is caused by magnetic fields. The electricity flows into the device which causes magnetic fields to grow and shrink along with the AC power. To keep it simple 120v AV power cycles from 120v down to -120v and back 60 times per second. This rise and fall in the electricity flowing is what causes the magnetic fields to grow and shrink. These magnetic fields are what make the impeller (spinning part) of the pump spin. These magnetic fields often travel farther that the equipment regardless of what the equipment is made of.

When we generate electricity we do it the other way around... we physically spin magnets close to coils of wire and the interaction of the magnetic fields moving across the wire cause electricity to be generated.

This happens anytime a magnetic field crosses something capable of conducting electricity. Including the salt water in your tank.

The motors in your tank are not leaking electricity. The magnetic fields moving through the water are creating it. With multiple pumps and magnetic fields a lot of power can potentially be created.

With no ground probe there is zero risk to the fish... yes we are generating a voltage but there is nowhere for it to go so no power actually flow anywhere (current) so nothing gets shocked. The danger is that now we can build up some more voltage or Potential for power to flow... my tank was at 80V when i got home.. it changes based on the speed of my powerheads. When you touch the water now the electricity stored in the tank has somewhere to go by going through you. You get shocked.

Electricity is lazy and will always take the easiest way out to ground. So if you properly install the ground probe that will ALWAYS be the easiest way for it to go and most of it will go that way... like water washing away dirt before wearing away rocks.

The downside to the probe is now that electricity being CREATED in your tank has somewhere to go so there will always be some electricity flowing through the tank. Since it is flowing electricity that can harm things electrical theory tells us this could harm your fish, the results in the article, and my own results agree, show such small ammounts of power flow that the risk to the inhabitants is actually quite minimal.

The article also points out that even with the ground probe in place, IF a cord became damaged dangerous amounts of available power will be present in the tank. This is the reason for using a GFCI. If the power leak was big enough it could eventually trip a breaker but that would be a pretty serious short and probably kill your tank. The GFCI will trip as soon as it sees some of the power it sends out not come back, at amounts small enough that no one gets hurt. The down side to the GFCI is that sometimes for no good reason pumps and motors will make them trip and now your tank has turned off. So no perfect solution.

Okay that last paragraph got slightly off topic, but still related topic???? Anyway great article you linked even if tough to get through. Google Electromagnetic Induction if my explanation on that didn't make sense, there are even some okay you tube vids about it.

POI - My Skimmer and Return pump seem to both generate around the 20V mark in my tank. My lights negligible (LED with drivers not in the housing) and my MP40's (no electrical components physically in the water) start to have an effect around 50% speed which makes sense as amount of interaction between water and magnetic fields increases as they spin faster.