125G Reefer
New member
Takes a MOD for anyone to open their eyes.
Is stray Current Normal?
- Thread starter caliking
- Start date
Takes a MOD for anyone to open their eyes.
iamwrasseman
New member
in respect to different people having different sensitivity to voltage that usually comes down to their sweat level in their shoes and what type of shoes they have on . when i have sneakers on and its winter i have rarely been hit by any voltage "tingling " . on a hot summer day when i have been working hard and i enter someones house and take off my sneakers with damp socks i make a much better ground and have been hit a couple of times .put my sneakers on and it goes away ,so theres something there for sure .
The MOD's experience proved to be incorrect because the OP saw a voltage > 50 with 0 current, meaning it's induced voltage and not a real equipment failure.... I'd wager that if he had the MOD's meter, it probably wouln't read 50, it'd probably read 5 or less.
It's not that the MOD's experience is wrong, it's just incomplete. Again, multimeters aren't designed for measuring induced voltages (lots of details above on why). The results are unpredictable, that's why there's so much confusion about it.
The first thing everyone says on here when someone is having a problem is that "we need more information, what are your parameters?" If you tell me that you're seeing 50V when you plug in your heater, my response is that "i need more information, what is the current?"
wholelottawater
New member
I always love this. Working in manufacturing I get the opportunity to challenge the design engineers theory all day long so I know exactly what you are saying.
I appreciate your experience and agree that faulty equipment could be found this way and many people have.
If you want to take this measurement for information purposes go ahead.
It just important to remember that all meters are different. Tanks are different all equipment and different. Many outcomes are possible so do not panic if you have nothing going wrong in your tank. IMO.
I will take it will a grain of salt just like the measurement in question.
not to beat a dead horse, but here's an example. My tank, two meters, two drastically different results.
I checked both meters via house voltage. The CenTek meter read 121.6V. The Tektronix meter read 122V.
The results on the tank are drastically different though. I'll tell you that the current on my tank reads 0, so there's no problem with the equipment.... Which meter to i trust? The $10 harbor freight cheapie that reads 5v, or the $75 tektronix meter that reads >30?
I checked both meters via house voltage. The CenTek meter read 121.6V. The Tektronix meter read 122V.
The results on the tank are drastically different though. I'll tell you that the current on my tank reads 0, so there's no problem with the equipment.... Which meter to i trust? The $10 harbor freight cheapie that reads 5v, or the $75 tektronix meter that reads >30?
125G Reefer
New member
:deadhorse::deadhorse::deadhorse::debi: Die horsy die........
Thanks for your help.. Much appreciated. :bounce2:
At least now i feel safe knowing there is no current even though there is phantom voltage.
At least now i feel safe knowing there is no current even though there is phantom voltage.
not to beat a dead horse, but here's an example. My tank, two meters, two drastically different results.
I checked both meters via house voltage. The CenTek meter read 121.6V. The Tektronix meter read 122V.
The results on the tank are drastically different though. I'll tell you that the current on my tank reads 0, so there's no problem with the equipment.... Which meter to i trust? The $10 harbor freight cheapie that reads 5v, or the $75 tektronix meter that reads >30?
Garydan - just to make sure I understand, if the current measures anything other than 0 mA then there's likely a problem (assuming, as you reasonably do, that there's no chemistry-related reason for a mA current)?
Mike31154
New member
Measuring current can be an even trickier process than voltage. Did you use only the mA range or did you try a higher range? Some meters will have a separate socket for your test lead designed for measuring current higher than mA. Also, if you don't have the correct range selected for the amount of current or voltage you're trying to measure, a digital meter will often flash some numbers & then read 0 or 1, indicating that you're not on the correct range setting.
Another point worth mentioning. In attempting to measure current you are actually causing current flow where there might otherwise be none by providing a path to ground through the meter for any voltage potential that may be present in your tank water. So if there is a 50 volt potential in your water, if you're performing the current measurement correctly, physics says you should definitely see some current.
A quick web search will show that ~65 mA through the heart can kill you, and people can feel somewhere between 1/2 and 10 milliamps, so you'll certainly know if you have more than a few milliamp without ever using the meter...
You should be able to read 0. If you don't read 0, i see two possible sources for the current. Chemical reactions, or equipment failure. Chemistry aside, the obvious cause is equipment failure. The current has to be coming from somewhere.
Do you have a problem if you read more than 0? That's really a question of how much current leaking is OK. I have no clue. I have a failed skimmer pump that reads 17 micro amp, so i know this approach worked to detect that pump. I also know that i saw no ill effects to the tank with it leaking 17 micro amp... Better safe than sorry? sure. Mostly harmless at such a small leaked current? probably.
As an additional oddity that i think is funny, when reading voltage with my failed skimmer pump plugged in, one meter reads more voltage, the other reads less.
You should be able to read 0. If you don't read 0, i see two possible sources for the current. Chemical reactions, or equipment failure. Chemistry aside, the obvious cause is equipment failure. The current has to be coming from somewhere.
Do you have a problem if you read more than 0? That's really a question of how much current leaking is OK. I have no clue. I have a failed skimmer pump that reads 17 micro amp, so i know this approach worked to detect that pump. I also know that i saw no ill effects to the tank with it leaking 17 micro amp... Better safe than sorry? sure. Mostly harmless at such a small leaked current? probably.
As an additional oddity that i think is funny, when reading voltage with my failed skimmer pump plugged in, one meter reads more voltage, the other reads less.
Last edited:
alton
Well-known member
I wrote this article back in 2006 (Sorry it is long but hopefully it helps)
Stray Voltage
Before I get started “I DO NOT RECOMMEND” to anyone to do the things I have done for my test!
With that I am covering Stray Voltage in and around your aquarium. This does not cover stray current in your tank! If you are getting a tingle when you touch your water, find out what is causing it and remove it, do not go out a buy a grounding probe thinking this will fix the problem. I recommend only using power heads and other equipment that is grounded (Has three prongs). I have never had problems with stray voltage or so I thought till last week when I checked all three of my aquariums. The reason I say that is because I am barefooted on a tile floor with my hands and arms submerged all the time with no tingle, so how could I have voltage? I have checked in the past with a meter with no voltage showing. Just recently I had made changes to my 200 gallon aquarium, but I figured no tingle no voltage right? The following is what I came up with all electrical equipment and lighting for the following tanks:
Tank #1 - 200 gallon, wet dry filter system, Mag. pump for the skimmer, Pan World 100PXX for the return. On lighting, 2 – 250 watt MH, 4 – 54w T5HO, 1 – 160 watt VHO.
Stray voltage – 14.5 volts and yes no tingle, even when I was barefooted and wet floor. Turn off the metal halides and it drops to 8.5 volts, turn off the rest of the lighting and it drops below 2 volts. For a clarification my hood is brand new, with no salt crepe or moisture and the lamps are a minimum of 8” above the water.
Tank #2 – 155 gallon, wet dry filter system, Mag. pump for the skimmer, Pan World 50PXX for the return. On lighting, 2 – 250 watt MH mounted in a 5’ Orbit light
Stray voltage – less than .5 volts with everything running. Clarification light is metal and grounded and the tank has glass tops.
Tank #3 – 29 gallon with an eclipse three filter system. The lighting consists of a 96 watt Quad PC with a 2 ½” fan from Radio Shack for cooling.
Stray voltage – 9 volts and once again no tingle. I grounded the reflector and the voltage only dropped a volt. Turn off light and voltage is below .5 volts. For clarification once again no moisture everything is dry, lamps is mounted only 3” above the water.
Solution: Installed a grounding probe into sump of tank #1 and one into the tank of #3 and voltage dropped below one volt in each.
GROUNDING PROBE – Good or Bad?
Let’s cover the bad things first:
If your service ground is bad outside it will use your tank as a ground and you will get more than a tingle. Example I got a call from a friend and he told me he was getting shocked when he put his hand in his tank. So I took a voltage reading and only 5 volts to the meter but to the hand it wasn’t very pleasing. Took out the grounding probe and voltage and shock was gone. I went to the service and added another ground rod and it took care of the problem. He left the probe out of his tank.
If you have a lightning strike near your home you have a chance of the voltage finding your way into your tank.
If you are going to install a grounding probe lets cover the basic setup for a safe operation:
Check your service for a ground rod some homes in SA do not have one. Go to where your meter is and look below your service panel or disconnect for#6 or larger wire leading into the ground. The ground rod should be buried below. If you cannot find one call an electrician to install one. If you are in soil keep the area moist especially now in dry times, this the main reason we lose our grounding. If you are in rock same thing make sure and keep the soil wet because you have less soil and solid rock does not make a good grounding substance. If you are building a new home add an additional grounding source to your ground rod by attaching a grounding conductor of #4 copper wire to a minimum of 20’ of rebar in your slab and attach it in two places and then attach it to your service panel grounding bar. To check and make sure you do not any voltage on your grounding conductors take your meter and place the probes across the grounding (green) and grounded (White) slots of several receptacles through out your house, the voltage should be 0. And then attach the probes across the ungrounded (black or red) slot and the grounding slot, and then the ungrounded slot and grounded slot. Determining which slot is which is easy. Looking at the receptacle the “U” shaped one is the grounding. The largest of the straight slots is normally the grounded with the smaller of the two being the hot or ungrounded. If you have voltage from the grounded and grounding slots (1 to 50 volts) you have poor grounding, call an electrician. If you have 120 volts then your grounded and ungrounded conductors could be reversed. (Call an electrician) Remember black or red goes on gold and white goes on silver, and of course the green or bare wire goes on the green terminal.
If everything is perfect than install your grounding probe, but don’t forget about it every once in a while you will need to check for voltage. It’s just like checking your GFCI receptacles to make sure they are working properly. Just because you have one doesn’t mean you’re safe. That is why there is a test button.
Stray Voltage
Before I get started “I DO NOT RECOMMEND” to anyone to do the things I have done for my test!
With that I am covering Stray Voltage in and around your aquarium. This does not cover stray current in your tank! If you are getting a tingle when you touch your water, find out what is causing it and remove it, do not go out a buy a grounding probe thinking this will fix the problem. I recommend only using power heads and other equipment that is grounded (Has three prongs). I have never had problems with stray voltage or so I thought till last week when I checked all three of my aquariums. The reason I say that is because I am barefooted on a tile floor with my hands and arms submerged all the time with no tingle, so how could I have voltage? I have checked in the past with a meter with no voltage showing. Just recently I had made changes to my 200 gallon aquarium, but I figured no tingle no voltage right? The following is what I came up with all electrical equipment and lighting for the following tanks:
Tank #1 - 200 gallon, wet dry filter system, Mag. pump for the skimmer, Pan World 100PXX for the return. On lighting, 2 – 250 watt MH, 4 – 54w T5HO, 1 – 160 watt VHO.
Stray voltage – 14.5 volts and yes no tingle, even when I was barefooted and wet floor. Turn off the metal halides and it drops to 8.5 volts, turn off the rest of the lighting and it drops below 2 volts. For a clarification my hood is brand new, with no salt crepe or moisture and the lamps are a minimum of 8” above the water.
Tank #2 – 155 gallon, wet dry filter system, Mag. pump for the skimmer, Pan World 50PXX for the return. On lighting, 2 – 250 watt MH mounted in a 5’ Orbit light
Stray voltage – less than .5 volts with everything running. Clarification light is metal and grounded and the tank has glass tops.
Tank #3 – 29 gallon with an eclipse three filter system. The lighting consists of a 96 watt Quad PC with a 2 ½” fan from Radio Shack for cooling.
Stray voltage – 9 volts and once again no tingle. I grounded the reflector and the voltage only dropped a volt. Turn off light and voltage is below .5 volts. For clarification once again no moisture everything is dry, lamps is mounted only 3” above the water.
Solution: Installed a grounding probe into sump of tank #1 and one into the tank of #3 and voltage dropped below one volt in each.
GROUNDING PROBE – Good or Bad?
Let’s cover the bad things first:
If your service ground is bad outside it will use your tank as a ground and you will get more than a tingle. Example I got a call from a friend and he told me he was getting shocked when he put his hand in his tank. So I took a voltage reading and only 5 volts to the meter but to the hand it wasn’t very pleasing. Took out the grounding probe and voltage and shock was gone. I went to the service and added another ground rod and it took care of the problem. He left the probe out of his tank.
If you have a lightning strike near your home you have a chance of the voltage finding your way into your tank.
If you are going to install a grounding probe lets cover the basic setup for a safe operation:
Check your service for a ground rod some homes in SA do not have one. Go to where your meter is and look below your service panel or disconnect for#6 or larger wire leading into the ground. The ground rod should be buried below. If you cannot find one call an electrician to install one. If you are in soil keep the area moist especially now in dry times, this the main reason we lose our grounding. If you are in rock same thing make sure and keep the soil wet because you have less soil and solid rock does not make a good grounding substance. If you are building a new home add an additional grounding source to your ground rod by attaching a grounding conductor of #4 copper wire to a minimum of 20’ of rebar in your slab and attach it in two places and then attach it to your service panel grounding bar. To check and make sure you do not any voltage on your grounding conductors take your meter and place the probes across the grounding (green) and grounded (White) slots of several receptacles through out your house, the voltage should be 0. And then attach the probes across the ungrounded (black or red) slot and the grounding slot, and then the ungrounded slot and grounded slot. Determining which slot is which is easy. Looking at the receptacle the “U” shaped one is the grounding. The largest of the straight slots is normally the grounded with the smaller of the two being the hot or ungrounded. If you have voltage from the grounded and grounding slots (1 to 50 volts) you have poor grounding, call an electrician. If you have 120 volts then your grounded and ungrounded conductors could be reversed. (Call an electrician) Remember black or red goes on gold and white goes on silver, and of course the green or bare wire goes on the green terminal.
If everything is perfect than install your grounding probe, but don’t forget about it every once in a while you will need to check for voltage. It’s just like checking your GFCI receptacles to make sure they are working properly. Just because you have one doesn’t mean you’re safe. That is why there is a test button.
Alton, great writeup for your experience, but the problem is that what you see for your meter does not equal what i see with my meter, and as i show above what you will see on your own tank with two different meters can be drastically different and in direct contradiction with each other. Have you tried with different meters? Being an electrician, you probably have a few different meters, have you gone through them to compare what they read? Have you tried reading current?
The problem is, volt meters are not designed to measure voltage on a floating wire and the results depend on the meter. The mystical "stray voltage" measurement isn't going to read the same for two different models of meters.
From an EE perspective, knowing how the meters work and their limitations, the only thing that makes sense is to measure current. Voltage just doesn't make sense.
The problem is, volt meters are not designed to measure voltage on a floating wire and the results depend on the meter. The mystical "stray voltage" measurement isn't going to read the same for two different models of meters.
From an EE perspective, knowing how the meters work and their limitations, the only thing that makes sense is to measure current. Voltage just doesn't make sense.
BeanAnimal
Premium Member
alton:
attempting to measure voltage in your aquarium is somewhat meaningless. What we are concerned with is current flow. Measuring a floating voltage with a handheld meter is not going to give you an accurate view of the situation and the reading will depend on numerous factors, but mostly the impedance of the meter and that of the source voltage. Measuring current however, is straight forward and will give a better picture of what is going on in the system.
That said, even the current measurements can be suspect, as the meter impedance has to compete with other ground paths (pumps shafts for example) in the tank. Remember, electricity does not take the path of least resistance, it takes all paths in proportion to their resistance.
Moving forward:
Your assessment of ground probes is fairly decent with regard to the CONS associated with them but your advice with regard to electrical service grounding has some faults (no pun) in it.
While I am not going to advise against code, I will say that numerous studies have shown that most ground rods are as good as useless at providing a true earthed connection. The connection to the cold water pipe is MUCH better, but in many cases is also as good as useless. The only ground reference that we can really count on to clear a fault is the center tap on the pole that we bond our ECG to! I still drive my two ground rods and bond to the cold water inlet, as it can't hurt to try to earth the connection....
Testing for ZERO voltage between the ECG and NEUTRAL at the receptacle can be misleading. If we do get a reading, then we still need to determine of we have a poor bond at the main panel, a fault somewhere upstream or induced voltage/current due to proximity to other fixtures. Again, meters can lie based on their input impedance and what they are connected to.
In any case you have actually overlooked the MOST IMPORTANT consideration when installing a grounding probe in an aquarium: ALL of the devices connected to the aquarium really MUST be GFCI protected. Adding the grounding probe to the aquarium introduces fault scenarios that do not exist without the probe. That is, GFCIs are important, but you should NEVER run a grounding probe WITHOUT full GFCI protection of the equipment in or around the aquarium.
The easiest example to illustrate the danger introduced by the ground probe is an aquarium with a light fixture where salt creep energizes an ungrounded reflector. There are dozens of OEM and DIY fixtures that utilize ungrounded reflectors.
In a setup without a ground probe, a person leaning into the tank and also touching the reflector will not likely get shocked, as there is no path for the current to flow. The reflector stays happily energized but is insulated from ground through the high impedence of your body and the ungrounded tank water.
In a setup with a ground probe, a person leaning into the the tank and also touching the reflector creates a path to ground from the fixture, through their body and into the tank water that is grounded. If there is a GFCI, then it will trip. If there is NOT a GFCI then shock or electrocution is immanent.
attempting to measure voltage in your aquarium is somewhat meaningless. What we are concerned with is current flow. Measuring a floating voltage with a handheld meter is not going to give you an accurate view of the situation and the reading will depend on numerous factors, but mostly the impedance of the meter and that of the source voltage. Measuring current however, is straight forward and will give a better picture of what is going on in the system.
That said, even the current measurements can be suspect, as the meter impedance has to compete with other ground paths (pumps shafts for example) in the tank. Remember, electricity does not take the path of least resistance, it takes all paths in proportion to their resistance.
Moving forward:
Your assessment of ground probes is fairly decent with regard to the CONS associated with them but your advice with regard to electrical service grounding has some faults (no pun) in it.
While I am not going to advise against code, I will say that numerous studies have shown that most ground rods are as good as useless at providing a true earthed connection. The connection to the cold water pipe is MUCH better, but in many cases is also as good as useless. The only ground reference that we can really count on to clear a fault is the center tap on the pole that we bond our ECG to! I still drive my two ground rods and bond to the cold water inlet, as it can't hurt to try to earth the connection....
Testing for ZERO voltage between the ECG and NEUTRAL at the receptacle can be misleading. If we do get a reading, then we still need to determine of we have a poor bond at the main panel, a fault somewhere upstream or induced voltage/current due to proximity to other fixtures. Again, meters can lie based on their input impedance and what they are connected to.
In any case you have actually overlooked the MOST IMPORTANT consideration when installing a grounding probe in an aquarium: ALL of the devices connected to the aquarium really MUST be GFCI protected. Adding the grounding probe to the aquarium introduces fault scenarios that do not exist without the probe. That is, GFCIs are important, but you should NEVER run a grounding probe WITHOUT full GFCI protection of the equipment in or around the aquarium.
The easiest example to illustrate the danger introduced by the ground probe is an aquarium with a light fixture where salt creep energizes an ungrounded reflector. There are dozens of OEM and DIY fixtures that utilize ungrounded reflectors.
In a setup without a ground probe, a person leaning into the tank and also touching the reflector will not likely get shocked, as there is no path for the current to flow. The reflector stays happily energized but is insulated from ground through the high impedence of your body and the ungrounded tank water.
In a setup with a ground probe, a person leaning into the the tank and also touching the reflector creates a path to ground from the fixture, through their body and into the tank water that is grounded. If there is a GFCI, then it will trip. If there is NOT a GFCI then shock or electrocution is immanent.
Last edited:
BeanAnimal
Premium Member
That is exactly the point Mike! Floating voltages are hard to measure and may not be enough to induce current flow. Placing a test lead in a tank and measuring "50 volts" is rather meaningless, as we do not know if we are actually measuring "50 volts" or the meter is giving a false reading due to an impedence mismatch with the source of the voltage.
If on the other hand, we can get current to flow, then we know we have a voltage source to drive that current, and thus we have a problem.
In other words, of no current flows, there is no problem. If current flows, there is a problem.
BeanAnimal
Premium Member
What gets interesting is different peoples sensitivity to the voltage. I've had staff and students reported feeling a "tingling" sensation or shock in tanks where I've felt nothing. Typically, breaking out the old voltmeter has shown levels around 30 to 60 volts. Measured this too many times with too many different meters to be willing to chalk up my safety or anyone elses to the idea that it's just meter inaccuracy. Anyone who wants to wait till they see some nice full blown electrolysis of a major failure is welcome too, but I'll never advise it
The difference in the thresholds is due to the differenfce in body chemistry between people. Your skins resistance (and that of your internals) can change depending on diet, time of day, medication, etc. Couple that with the general fact that each of us has a slightly different threshold with regard to sensory perception and you can see what some folks feel a tingle and others feel nothing. I might also add that a cut or breach of the out layers of skin is a breack in our insulation and more than likely will result in feeling a shock where you wouldn't if there was no cut
Your observations are correct and in general expected, even to the point that if you measure a substantial VOLTAGE in the system, then there is likely a real fault and not an induced voltage. That said, testing for current flow removes any question as to the validity of the voltage reading
I got a light shock when I reached in a tank at school after putting in a powerhead.
surferboi2113
New member
Hi guys i'm interested also. Sorry to the OP if this is hijacking.
I get a small shock through a cut on my finger. Very small, but noticeable. Will my inhabitants be fine for the time being? until i have time to properly fix the issue? I wont be able to spend much time with the tank this month as i am away. if need be i can get the caretaker to change out the faulty equipment, he does the weekly water changes etc...knows a little, but not as much as i would like. i would rather do it myself when i have time.
Suggestions? anyone have the same experience? Are there any longterm affects?
Again sorry for the hijack, i can repost if need be. Cheers!
I get a small shock through a cut on my finger. Very small, but noticeable. Will my inhabitants be fine for the time being? until i have time to properly fix the issue? I wont be able to spend much time with the tank this month as i am away. if need be i can get the caretaker to change out the faulty equipment, he does the weekly water changes etc...knows a little, but not as much as i would like. i would rather do it myself when i have time.
Suggestions? anyone have the same experience? Are there any longterm affects?
Again sorry for the hijack, i can repost if need be. Cheers!
