When to deal with stray voltage.

[fab]

The question asked was "when" to check. The answer is as soon you setup March electrical item, whole you are filling your tank the first time, and as add any electrical items to your system. The occasionally after that and particularly whenever you fell a tingle or a shock when you touch anything in or near your system.

First priory is electrical current. That is what you do not want. Check for current between your saltwater and an electrical ground.

Waterjockey and redfishbluefish are right. You can check voltage differences along various paths from the water, itself, to ground, water to light fixtures, water to other devices and fixtures. And check for currents through those paths. Record your results for path, current and DC voltage and AC voltage.

Then turn everything off and check all the paths again. Then turn things on, one at a time, each time measuring voltage and current for each path. At each step measure and record both voltage and current. If there is any current at all measure both AC and DC voltage.

That is a lot of measurements and a lot of notes. Best done with an assistant to write the notes.

Let us know how you fared.

 

[Dom]

Hi Dom, did you try measuring if there was any current (likely in milliamps, if any)? Say between your stand and the ground plug on your outlet?

Cheers!

Amps = Zero when testing from ground plug to stand and ground plug to tank.

 

[saltyfilmfolks]

I think you need to test it differently, at the outlet itself as one person mentioned. Getting a reading using the stand as one leg of the measurement is disconcerting. Here's my article: http://www.reefaddicts.com/content.php/45-How-to-Test-for-Stray-Electricity

Always excellent articles. The stand reading is disconcerting but with stray voltage not unusual. It probably a good time to read up , and recheck all the findings so far. Dont get over whelmed its quite easy

But I've been metering electrical devices for some time (25+)and It would surprise most on how much voltage and current is actually coming off of a microwave or your shop light in the garage, and CRT tvs were also a great EMF maker.
So for many this is the first time they have actually noticed that this is happening.

Bottom line, it happens. If all the tests, esp polarity are correct, and no system grounds have been jumped, all equipt is working properly, Its likely this is the norm for your tank.

ALL AC powered devices will give off Electro Magnetic Fields EMF. These build up and will look for a place to go. Stray Voltage.
Put the EMF in a box of salt water and things get weird.
A ground probe will sent all that current and voltage to earth/ground in a path of little resistance.
With out a probe the voltage uses you as as that path.

DC does not give off the same type EMF. And will not seek a random earth or a ground like you or build stray current. It will only seek it's self.
That's why my tanks will very soon be all DC.

No. No. No.

You will learn much more by reading and engaging with others. Follow threads. Ask questions to clarify things that were not clear in your readings. Participate in dialogs. Test your ideas on others.

You will learn far less by being only passive. Until you do the work of carefully articulating your thoughts in spoken or in written words you are untested. You will learn from these efforts as your thoughts are proven to be either correct or flat wrong or just unclear.

@fab +1 + infinity. One GREAT thing about the folks on R2R is its a conversation. Not flaming not shaming. its thought provoking.
Well said sir.

 

[Dom]

Use an outlet....if need be, with an extension cord. Ideally use the "ground" hole for the probe. If not the ground hole, the screw holding the cover plate on would work as well.

Amps = Zero from ground to stand and ground to tank.

 

[saltyfilmfolks]

FWIW poorly insulated cables(chinese powerheads), give off more emf. Cheap Powerstrips with small gauge wiring inside create resistance producing more EMF at the device.

 

[saltyfilmfolks]

Amps = Zero from ground to stand and ground to tank.

Thats soo good. Volts are what hurt, amps do damage.

 

[fab]

Current will also plate metals to other metals through conductive water, particularly through saltwater. Generally this will just cause some pitting in the donor metal, but over a long time could become quite unsightly and even affect function.

 

[fab]

My goal is 5v or less.
I'm thinking about building a new stand (wood).

Don't bother. Avoid wasteful work on a wooden stand unless you want to build it for aesthetic reasons.

Apparently you have no electrical current through the stand. The stand is not a problem. If you are really worried over this just add a 1/8 inch sheet plastic (4x8 sheets at home depot) or 1/2" plywood between tank and stand.

I have a stainless steel stand with the plywood on top and the sheet plastic on top of the plywood. I use the plastic to help separate the tank and wood from each other as a moisture mitigation step, not for electrical insulation.

 

[Dom]

Don't bother. Avoid wasteful work on a wooden stand unless you want to build it for aesthetic reasons.

Apparently you have no electrical current through the stand. The stand is not a problem. If you are really worried over this just add a 1/8 inch sheet plastic (4x8 sheets at home depot) or 1/2" plywood between tank and stand.

I have a stainless steel stand with the plywood on top and the sheet plastic on top of the plywood. I use the plastic to help separate the tank and wood from each other as a moisture mitigation step, not for electrical insulation.

I'd have to empty out the whole tank and remove it to put down plywood.

 

[Dom]

Update

I've installed a titanium grounding rod. Volts = Zero. While this solves the voltage issue in the tank, it is still disturbing that all of this equipment is putting out so much into the tank.

What will be interesting to see is if my corals and nems start coming back

 

[saltyfilmfolks]

it is still disturbing that all of this equipment is putting out so much into the tank.

Make you want to meter a BIG tank..... Or a big CRT TV, if you have one laying around.
FWIW Im going DC.

 

[Dom]

Im going DC.

Ya know; I think that's a great idea. My primary circulating pump is about 6 years old. After this experience, I'm thinking it may be time to start replacing the worn out equipment. I'm going to research DC pumps.

 

[redfishbluefish]

A grounding probe alone is not the solution. With the probe you now have current....and that's a problem. You need to identify the source of the voltage and take care of it. A small amount of induced voltage is OK.

 

[Dom]

A grounding probe alone is not the solution. With the probe you now have current....and that's a problem. You need to identify the source of the voltage and take care of it. A small amount of induced voltage is OK.

Well; the source is equipment required to run the tank. I have a brand new power head that's putting in about 4 volts. Whats the answer? By nature, this stuff puts voltage in the tank. I'm going to take current readings.

 

[saltyfilmfolks]

A grounding probe alone is not the solution. With the probe you now have current....and that's a problem. You need to identify the source of the voltage and take care of it. A small amount of induced voltage is OK.

where does yours run. I havent really tested in a couple months. Sabeafell says his is 32v. no probe

 

[redfishbluefish]

Well; the source is equipment required to run the tank. I have a brand new power head that's putting in about 4 volts. Whats the answer? By nature, this stuff puts voltage in the tank. I'm going to take current readings.

I'm curious how you measure current in a fish tank?

I haven't read all posts, but I thought you had high voltage......4 volts is OK, with the majority likely coming from induced voltage....that is a magnet spinning in a field, acting like a mini-generator.

 

[redfishbluefish]

where does yours run. I havent really tested in a couple months. Sabeafell says his is 32v. no probe

I don't use grounding probes.....but if you do, they need to be used in conjunction with a ground fault....and that's the problem, because they trip too easily, now leaving your tank without flow (or whatever else is on that circuit.) And you know that's going to happen when you're not home.

 

[melev]

Well; the source is equipment required to run the tank. I have a brand new power head that's putting in about 4 volts. Whats the answer? By nature, this stuff puts voltage in the tank. I'm going to take current readings.

I provided you with an article on page one showing how to test everything one by one. This has nothing to do with your stand, and no I would definitely not take the tank down to add a sheet of wood for the purpose of insulating against electricity. However, putting a sheet of plywood between my steel stand and my glass aquarium is what the manufacturer told me to do. Plywood has a little give, where steel does not.

 

[Russ265]

this is why i dont do grounding rods...

you can jump up on an open cable of electricity and not feel a thing.

you ground yourself.... well. its lights out

 

[Dom]

I'm curious how you measure current in a fish tank?

I haven't read all posts, but I thought you had high voltage......4 volts is OK, with the majority likely coming from induced voltage....that is a magnet spinning in a field, acting like a mini-generator.

Without the grounding probe, I had around 45v! Now its zero with the probe installed. EVERYTHING running in the tank totals that 45v.

I'm going to figure out to check current.