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View Full Version : Stray voltage- what's yours'


jcw
09/06/2011, 09:46 AM
After feeling pain in a small cut on my finger this AM while reaching in the sump to change filter socks, I checked my 30g qt.

30g Qt(GCFI extension cord, no grounding probe)- 40V. Unbelievable. I probably could have been seriously hurt.
About 25-30 from a used Reef Octopus SSS Water Blaster pump. :mad2: About 5-10 from a used Eheim 1260. About 1-2 from Tunze ATO and a 6 month old Aqueon heater. Even turning on a MP40 increased it by 1V.
Everything I put in there the last 6 months has eventually died. Death toll at least four fish.

My 55g qt(GCFI extension cord, no grounding probe)- 15V. Most from a used Deltec HOB. :mad2:
Sucessfully QT'd a chocolate tang and currently a genicanthus angel is doing well. The angel did have a period of 3-4 days where it didn't eat well.

My 200g total water DT(GCFI outlets, no grounding probe)- 4-5V. About 1-2V from ATB sicce skimmer pump and 2 Eheim 1260 returns.
Ich near inception of the tank. But since then, everything has been fine and really doing well.



So, just wondering for those that have measured voltage in their tanks, what have you measured and have you had mysterious deaths or failure to thrive? even unusual skittishness in fish? Do you use GCFI circuits? grounding probes(measure with and without the probe plugged in)?

While I unserstand that different fish, coral, inverts will have different thresholds of tolerating voltage, I'm looking to see if there is a general number where voltage becomes detrimental to the livestock. A quick search didn't really reveal anything concrete.

Thanks.

jcw
09/06/2011, 09:49 AM
I should probably check the copper levels in that tank. :(

Iskandar
09/06/2011, 11:58 AM
Something to read on the matter:
http://angel-strike.com/aquarium/GroundingProbes.html
Citation:
"Voltage is not the problem, current is. Voltages can exist without there being any current. For example, birds sitting on a power line may be in direct contact with 10,000 volts, but they are not electrocuted. Why? Because no current is flowing through their bodies. Voltage is the “potential” or force that drives electrons through a conductor. The actual flow of electrons is the “current”. It is current that kills. Were one of the birds sitting on the power line to simultaneously touch one of the other wires on the transmission pole, a current path would be created (through the bird) and it would be electrocuted (and probably incinerated as well). So what are you doing when you add a grounding probe to your aquarium? You are providing a current path that might not already exist. Any fish between the source and the grounding probe will experience a current flowing through their bodies... not good!

Taking a volt meter and measuring a voltage in your aquarium relative to some arbitrary ground point does not indicate that there is a current flowing through the salt water (conductive medium) in your aquarium! It just means that the aquarium water is at a different potential than the ground reference point that you chose."

jcw
09/06/2011, 12:32 PM
Thanks. I've read that. And although grounding probes create current in a tank, the idea is that if you pair it with a gfci and remove the biggest electrical offenders, the resultant low level current is preferable to possible voltages.

http://www.reefs.org/library/aquarium_net/1298/1298_3.html

Something to read on the matter:
http://angel-strike.com/aquarium/GroundingProbes.html
Citation:
"Voltage is not the problem, current is. Voltages can exist without there being any current. For example, birds sitting on a power line may be in direct contact with 10,000 volts, but they are not electrocuted. Why? Because no current is flowing through their bodies. Voltage is the “potential” or force that drives electrons through a conductor. The actual flow of electrons is the “current”. It is current that kills. Were one of the birds sitting on the power line to simultaneously touch one of the other wires on the transmission pole, a current path would be created (through the bird) and it would be electrocuted (and probably incinerated as well). So what are you doing when you add a grounding probe to your aquarium? You are providing a current path that might not already exist. Any fish between the source and the grounding probe will experience a current flowing through their bodies... not good!

Taking a volt meter and measuring a voltage in your aquarium relative to some arbitrary ground point does not indicate that there is a current flowing through the salt water (conductive medium) in your aquarium! It just means that the aquarium water is at a different potential than the ground reference point that you chose."

jcw
09/07/2011, 07:14 AM
Well, and interesting development.

When I pulled the skimmer and pump, cleaned it and just for the heck of it tested it on another circuit, the meter didn't read any voltage.

I put it back in the tank and plugged it in with a long extension cord to another circuit and no voltage. In fact, no voltage from either the Eheim or the skimmer pump. What's also weird is that there is now a very slight 10mV reverse DC voltage from the tank to a copper pipe ground or the other circuit.

I'm no electrician so I can only guess that there must be some grounding issue with the outlets near the tank. Not sure why I'm measuring a DC voltage in the other circuit, though.


The HOB deltec pump is leaky a little however and needs to be replaced. I took it offline and I might be imagining things but it seems the angel is a little less skittish and swims right up to the glass when I walk by. :lmao:

Ron Reefman
09/07/2011, 07:28 AM
Something to read on the matter:
http://angel-strike.com/aquarium/GroundingProbes.html
Citation:
"Voltage is not the problem, current is. Voltages can exist without there being any current. For example, birds sitting on a power line may be in direct contact with 10,000 volts, but they are not electrocuted. Why? Because no current is flowing through their bodies. Voltage is the “potential” or force that drives electrons through a conductor. The actual flow of electrons is the “current”. It is current that kills. Were one of the birds sitting on the power line to simultaneously touch one of the other wires on the transmission pole, a current path would be created (through the bird) and it would be electrocuted (and probably incinerated as well). So what are you doing when you add a grounding probe to your aquarium? You are providing a current path that might not already exist. Any fish between the source and the grounding probe will experience a current flowing through their bodies... not good!

Taking a volt meter and measuring a voltage in your aquarium relative to some arbitrary ground point does not indicate that there is a current flowing through the salt water (conductive medium) in your aquarium! It just means that the aquarium water is at a different potential than the ground reference point that you chose."

Iskandar, great link man, thanks. I do electrical work all the time and didn't even give this a thought.

ultraxr
09/07/2011, 08:01 AM
man... that link does shed a lot of light on basic electrical fundamentals that we, people who do work on electrical gear everyday oversee.

110galreef
09/07/2011, 08:27 AM
how are you testing the stray voltage of the individual pieces? Just unplugging them.plugging them and seeing the change in the water?

jcw
09/07/2011, 10:01 AM
how are you testing the stray voltage of the individual pieces? Just unplugging them.plugging them and seeing the change in the water?

Yeah at first. Then as a final test I put the equipment in an old salt bucket filled with salt water plugged it in and tested each separately.

PoggiPJ
09/27/2011, 08:19 PM
I just did a test between my water surface and the reflector on my PC fixture. I'm getting 32VAC at 16 mA. I also have my main pump on a GFCI, which has been tripping every once in a while.

tkeracer619
09/27/2011, 08:39 PM
Reflectors should be grounded.

My tank runs mp40/60 and an external return pump w/ manifold for reactors. My heater when in the tank is not submerged. Lighting reflectors are all grounded.

The only power cord that is in the water is for my askoll skimmer pump.

voltage in my 360g = 3v from skimmer

I got a bad shock from some koralias (put me on my ***). That was all I needed to remove the cords for good. Eventually when I get some time I am going to turn my skimmer into a recirculating external and remove the last cord. The koralia brand was banned from my home and all products tossed in the trash (working and under warranty included).

ultraxr
09/27/2011, 09:37 PM
I just measured my tank's stray voltage and read 2.8 VAC.

Corded equipment in tank:
-Maxi-jet 900 (for my reactor)
-Sedra 5000 (pump for ASM G3 skimmer)
-Mag 12 (return pump)

This is the first time I measured stray voltage. Its crazy reading how high some people's are. I'll be measuring every time I place a corded piece of equipment in my system. I'm replacing my skimmer so I'll measure again after that too.

NanoReefWanabe
09/27/2011, 09:40 PM
I got a bad shock from some koralias (put me on my ***). That was all I needed to remove the cords for good. Eventually when I get some time I am going to turn my skimmer into a recirculating external and remove the last cord. The koralia brand was banned from my home and all products tossed in the trash (working and under warranty included).

arent all your pumps still in direct contact with the water through the drive shafts?

ultraxr
09/27/2011, 09:53 PM
But most/if not all pump drive shafts magnetically connected and driven.

fredg89
09/27/2011, 10:21 PM
take your multi-meter and change it from V to A or mA. As long as A and mA show 0 then your risk for electrician is 0, but I understand that stray voltage can be annoying. Kinda like when you touch someone and get a slight shock.

I'm not sure if grounding probes will cause harm or not so idk how to advise you on that.

acasp4
09/27/2011, 10:25 PM
If you have a ground probe in the tank will that totally eliminate stray voltage?

ultraxr
09/27/2011, 10:35 PM
Grounding probes can do either good or bad. It all depends where your stray voltage is coming from and if you have a good ground. Worse case, you put a grounding probe in and complete the path of current, resulting in fatal shock hazards. I suggest you locate and eliminate the cause of the stray voltage and current. Grounding probes is not a for sure fix.