Grounding Probe....

[ASaleem91]

So a couple of days ago I stuck my hand into my tank and felt a shock. At first I thought that some saltwater got into a cut of my but later I looked at my finger and realized that there was no cut. My finger stung for a couple minutes after I had stuck it in my tank. I then looked at some of my corals and realized that a couple of them were closed up when usually they were completely open. So I have come up with the conclusion that there is a some amount of voltage in my tank.

 

Some members of ReefCentral have told me to go out and buy a grounding probe and be done with the problem. Others have told me that if I do stick a grounding probe into the tank that it causes and electric current because it creates a circuit which could lead to my fish getting certain diseases.

 

I was wondering if any WAMAS members have been using grounding probes and what the pros and cons might be for using grounding probes? Also do grounding probes have to be plugged into a GFCI outlet or could the be plugged into an ordinary outlet and do the same thing?

 

Thanks,

Ali

[Origami]

Are you kidding? With all that electricity going into your tank, somebody's advising you NOT to get a grounding probe? Get a grounding probe. It could save your life. It's as simple as that. And, yes, they can work with just a plain old outlet. It's really nothing more than a titanium, or non-corrosive probe, that plugs into the earth ground of an outlet to keep any electrical potential from building up in the tank.

[ErikS]

No - simple as that.

 

Probe will not save your hide, a GFCI will - that's it's design.

 

Without a grounding probe = fish like bird on a wire, no effect

 

With a grounding probe = fish grounded, like you grabbing a power line = dead stuff

 

A grounding probe is like a ban-aid on an amputation...........might save you, but it's not the right approach.

 

GFCI should & in my opinion IS mandatory for tanks.............just like code requires them in bathrooms.

 

Solution -

 

1) use a multi-meter to figure out the offending unit, REMOVE it immediately

2) DO NOT put hands in tank until #1 is complete

 

Electricity, salt water, and a saline bag (you, humans) = not a good mix, not at all.

Edited April 16, 2008 by ErikS

[rsarvis]

Erik, are you saying you don't need/want a grounding probe AT ALL? Just have GFCIs and that's all you need?

 

I was actually planning on getting a grounding probe, too, after reading others' advice on here....

 

As for the GFCIs, one of the outlets I use is connected off of a GFCI, but one still isn't, and I've been wanting to swap that out. I actually bought a couple GFCI outlets about a year ago but when I went to install, there were more wires in the existing outlet than the instructions explained how to deal with, so I didn't know what to do and ended up never installing it. I'd like to, though; I like safety.

 

Anyone care to come over to give me a lesson in electrical wiring?

 

No - simple as that.

 

Probe will not save your hide, a GFCI will - that's it's design.

 

Without a grounding probe = fish like bird on a wire, no effect

 

With a grounding probe = fish grounded, like you grabbing a power line = dead stuff

Edited April 16, 2008 by rsarvis

[YBeNormal]

Yes, I use a grounding probe and I wouldn't have a saltwater tank set up without one. Yes, providing a source to ground closes the circuit and allows electricity to flow. That's good though 'cause it will be the path of least resistance and the preferred route for the current to take--rather than through my body. I'd much rather have the fish die and me live than the other way around. Just my humble opinion...

 

No, adding a grounding probe is not the solution to your problem. It is only a safety measure. You should always track down the source of the leak and correct it as soon as it is identified. The typical source is a powerhead or a shorted light fixture.

[jwildman]

I agree ... need both. Grounding probe will do no harm and will reduce/stop stray voltage. It does NOT in any way replace a GFCI. Also you should find the offending piece of equipment and replace it.

 

I also have found that have a probe in good working order will help with PH probe. See thread called PH way up.

 

Good Luck

 

John

 

 

Yes, I use a grounding probe and I wouldn't have a saltwater tank set up without one. Yes, providing a source to ground closes the circuit and allows electricity to flow. That's good though 'cause it will be the path of least resistance and the preferred route for the current to take--rather than through my body. I'd much rather have the fish die and me live than the other way around. Just my humble opinion...

 

No, adding a grounding probe is not the solution to your problem. It is only a safety measure. You should always track down the source of the leak and correct it as soon as it is identified. The typical source is a powerhead or a shorted light fixture.

[Hilary]

Grounding probe + GFCI for me.

[flowerseller]

Grounding chiller + GFCI for me.

[BeltwayBandit]

Ahh yes one of the classic 'arguments' among reefkeepers...

 

To ground or not to ground. That is the question.

Weather it is safer for the fish or the keeper to suffer

The ping and tingle of stray voltage

Or to put safety first

And by grounding, end them. To ground, with current...

No more... and with GFCI we prevent

The heartache, and the thousand natural shocks

That stray current leads to.

 

ok... enough butchering of Shakespeare.

 

There are two separate and distinct issues with grounding probes. Unfortunately these issues often get lumped together and thus the confusion is born.

 

There are two different sources of electric potential in your tank. Yes two. The first, is stray current from an improperly grounded or short circuited piece of equipment. If your equipment has a 3 prong plug, then it is likely that a short in the equipment will cause your GFCI to trip without a grounding probe. If you have any two prong (i.e. ungrounded) items, it is unlikely that your GFCI will trip without grounding the tank. I have been shocked by a tank, protected by GFCI, but ungrounded. It is entirely possible. In this scenario, grounding a tank should be a no brainer. If/when a piece of equipment shorts out there will be a momentary current from the equipment to the grounding probe. This will introduce an imbalance on the hot and neutral legs that your GFCI will detect and it will trip offline. We are talking less than a second here that current will flow through some portion of your tank. IMO that brief instant is not worth the risk of running a system ungrounded.

 

The second source of electric potential is not so clear cut. (and IMO the source of most of the confusion surrounding the issue). This involves induced voltages. I'm not going to go into the theory, but suffice it to say salt water is a good conductor of electricity and having electrical equipment in and around it can create an induced voltage. It is this stray voltage, that when left alone merely raises the electric potential of the tank, yet when a ground probe is introduced it will cause some minute (see link below to see how minute) amount of current to 'flow' through the tank. This is the current that the anti-ground probe folks are using to justify their opposition. I found the following paper on reefs.org that should throw cold water on this particular urban legend. As you will see, the induced current is so tiny (on the order of 10^-9) it truly can be considered trivial.

 

So, there you have it. That is my take on the issue.

 

BB

 

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

 

PS: please, no one post that horrible website from Georgia Tech on this subject. That paper has to be one of the worst articles I have ever read on this particular subject.

[YBeNormal]

Good explanation and I agree with your thoughts on the Georgia Tech article as well.

[ErikS]

I bet you'd be surprised that I agree with BB..............to a point of divergence.

 

I am not "anti-grounding probe", more along the lines it's unnecessary, and without a GFCI it can be dangerous.

 

They are often touted as a solution by those whose knowledge of electricity is at best limited - like the guys installing Arc Fault Breaker & can't tell you why or the difference between them & a GFCI.

 

You'll note in the OP's statement -

 

Also do grounding probes have to be plugged into a GFCI outlet or could the be plugged into an ordinary outlet and do the same thing?

 

This leads me to believe they do not use a GFCI outlet(s) - using a grounding probe in this circumstance can lead to trouble, at the very best it would be a band-aid solution. Yes, it could make the OP the 2nd best path to ground.............anyone think that's ideal?

 

Where BB & I diverge is whether or not a completed circuit is good or bad in a fish tank. I would agree given the devices we place in the tank it's almost impossible NOT to have some induced voltage in the tank. It just doesn't make any sense - all the components are there. There must be some present, even heavily shielded I think some would still be present. We know for a fact that even massive amounts of "potential" current aren't harmful to wildlife or humans (think clamping on to extremely high voltage lines)...............what we can argue is how harmful are small amounts of actual current to tank inhabitants. Given 60ma across the heart is likely fatal to a human...........what's fatal or bothersome to a fish? I'm not an Ichtyologist = I have no idea. I have seen a reaction to it by measuring the potential current in my tank - connect the circuit fish go a bit wild.............is it harmful? Can't say, max potential I've ever seen in my tank is about 47mv - pretty minor. So which is worse - the feeling from potential current or the actual current? I don't know, I asked but the fish didn't answer (when they do I'll post).

 

So why not use a grounding probe? Simple - what does it get you? Nothing, nada, zip, zero, zilch, bubkiss. If you have a properly functioning GFCI (which I view as mandatory) the probe is fairly redundant, it offers nothing.

 

1) how do you know the probe is even functioning? How did you test it? Just because you have a spoke connected to a grounded outlet means little. And if it did work when installed - how do you test it? How often? Corrosion & other factors can cause it to be useless

 

2) A properly functioning GFCI will protect you from death or injury. It's easy to test, push the button. Functionality is critical - that's why it has the button. Easy to test & keeps you alive - what more do you want?

 

Yes, you can get a shock even when protected by a GFCI............but that's the design. Working properly it will trip in milliseconds = it will trip before you are injured. Will you feel it? Maybe, but you'll be able to talk about it.

 

Like many things in this hobby...............it's your call, call the ball.

[Origami]

GFCI's are residual current devices, or RCD's. They essentially work by detecting a current imbalance between the two legs of a circuit. By shunting the residual current from a leaky (or faulty) device into a grounded (not neutral) line, you are more likely to trip a GFCI.

 

You can also shunt the residual current with your body, provided you can provide a path to ground, and trip the GFCI that way. If you don't provide that path, it's as Erik says: You're like a bird on a wire. However, if you're feeling a tingle, you're not a bird on a wire - you're just a wire. Possibly a high impedance wire, but a wire nonetheless. It's a sign that something's amiss. And it doesn't take a whole lot to set your heart into fibrillation (provided the current crosses your heart). That level is only on the order of 40-50 milliamps. A working GFCI will trip before this level as well.

 

Thus a GFCI is your first line of defense in both of these situations. Personally, I'd prefer the former because I don't have to be there to provide the alternate path to trip the GFCI.

 

Alternately, you can use a grounding probe without a GFCI but, in the event of a faulty device, it does create a relatively high-capacity path to ground for current to flow - and current will flow in that case. Current in and of itself, however, is not a problem. It's when it passes through living tissue that it causes trouble. Given the choice of a low impedance path to ground (the grounding probe) and the higher impedance path to ground (your body), the majority of current will pass take the path through the probe. However, this doesn't mean that you'll feel nothing. I see two possible effects here that the body provides: First, there's an alternate path to ground through your body - say from you hand through your feet; Second, there's a parallel path to the grounding probe (across the hand in the water). The first is the dangerous path; the second is the inconvenient path. Use of a grounding probe mitigates the risk of the first path by introducing the second path. Thus, I still believe that a grounding probe has safety value without a GFCI, if only as a back up to a failed GFCI. Mind you, I'm less concerned about the fishes than I am the reefkeeper in this situation. This is why the NEC (National Electrical Code) calls for grounding in so many situations, including metal ladders for swimming pools, cold water pipes (copper) in your home, metal surfaces within 6' of pools, etc.

 

That said, though, I agree that a grounding probe used in conjunction with a GFCI is the best way to go. It is, by the way, the way I have my tanks set up.

Edited April 16, 2008 by Origami2547

[BeltwayBandit]

Just to clarify, I would NEVER put a grounding probe on a non GFCI protected system. If I had a non-GFCI system I would make darn sure that I am insulated from ground before reaching into the tank.

 

I bet you'd be surprised that I agree with BB..............to a point of divergence.

 

 

Actually, I'm not surprised at all.

 

 

So why not use a grounding probe? Simple - what does it get you? Nothing, nada, zip, zero, zilch, bubkiss. If you have a properly functioning GFCI (which I view as mandatory) the probe is fairly redundant, it offers nothing.

 

1) how do you know the probe is even functioning? How did you test it? Just because you have a spoke connected to a grounded outlet means little. And if it did work when installed - how do you test it? How often? Corrosion & other factors can cause it to be useless

 

It is very simple to periodically test it with a multimeter. Pull the probe out of the water, touch hot with one lead of your multimeter, touch the probe with the other. If your GFCI trips, it works. Pretty quick and simple and you have just tested both the probe and the GFCI.

 

2) A properly functioning GFCI will protect you from death or injury. It's easy to test, push the button. Functionality is critical - that's why it has the button. Easy to test & keeps you alive - what more do you want?

 

I prefer to not make myself the path to ground in order to get the GFCI to work. And, I prefer not to jeopardize my health on a single point of failure system. What happens if the GFCI doesn't work? Well your heirs will have a nice lawsuit against the manufacturer, your still dead.

 

Yes, you can get a shock even when protected by a GFCI............but that's the design. Working properly it will trip in milliseconds = it will trip before you are injured. Will you feel it? Maybe, but you'll be able to talk about it.

 

Like many things in this hobby...............it's your call, call the ball.

 

It is a fundamental tenant of electrical safety to design a system that attempts to eliminate any possible interactions between humans and electricity to the extent possible. A grounding probe does that, with your philosophy you are OK with making yourself the grounding probe. A competent electrical engineer would not design a system that required a human ground in order to go to a safe mode.

[yauger]

what meter can I use to find out if there is a current running in my water? and how do I find out what equipment is the culprit? How does someone with no electrical experience perform these tasks?

[ErikS]

Just to clarify, I would NEVER put a grounding probe on a non GFCI protected system.

Which is exactly what you'll often see in threads - no real reasoning "add a grounding probe".............because someone told them to Which is the type of information the OP seemed to be getting, not how to really solve/address the issue.

 

It is a fundamental tenant of electrical safety to design a system that attempts to eliminate any possible interactions between humans and electricity to the extent possible. A grounding probe does that, with your philosophy you are OK with making yourself the grounding probe. A competent electrical engineer would not design a system that required a human ground in order to go to a safe mode.

Yep, but that's exactly how they set up the standards for home wiring - you're the grounding probe. Much less an issue with newer insulated devices, but still in the event of contact who's the probe?

 

And given this design was allowed to go forward I tend to lose a bit of faith in the engineers (DE MH socket) -

 

 

Maybe we should start a poll - last time we tested our GFCI's? (me = 3-10-2008, I'm overdue).

 

And we all have our "limits", sadly I rarely check the potential current in the tank.........most often only when I add new equipment - should do it with the GFCI test.

 

And on the funny side even after years I STILL don't really enjoy having both hands in the tank - I much prefer only one at a time.

 

what meter can I use to find out if there is a current running in my water? and how do I find out what equipment is the culprit? How does someone with no electrical experience perform these tasks?

Multi-meter. Red in tank, black to ground - ideal is 0. Likely you will get a mv (milli-volt) reading. On a GFCI circuit if the voltage isn't small it will/should cause the GFCI to trip (see BB's post on testing) To identify the offender you simply remove all devices & return them to service one by one until you find the one that causes the problem.

Edited April 16, 2008 by ErikS

[BeltwayBandit]

 

Just to clarify, I would NEVER put a grounding probe on a non GFCI protected system.

 

Which is exactly what you'll often see in threads - no real reasoning "add a grounding probe".............because someone told them to Which is the type of information the OP seemed to be getting, not how to really solve/address the issue.

 

When taken in conjunction with the rest of the thread, I didn't feel it was necessary to reiterate the reason why. A ground probe on a non-GFCI protected tank will provide a path to ground for stray current. In the event of equipment failure this will set up a live circuit through the tank. This will likely not be enough to trip the circuit breaker for the system. Thus, the aquarist has no indication that there is a problem in the tank and can get a shock when they touch the water. Again, my basic philosophy is human conduit for electrical current = bad. You have not eliminated this possibility with just a grounding probe. Not to mention the damage you could do to the critters in your tank by having a significant current flowing through the tank, as opposed to the insignificant current created by induced voltages.

 

lol.gif Yep, but that's exactly how they set up the standards for home wiring - you're the grounding probe. Much less an issue with newer insulated devices, but still in the event of contact who's the probe?

 

There is also the concept of risk analysis in play here. In the normal household the risk of exposure to current from an ungrounded circuit is significantly less than when you add highly conductive saltwater or any water to the mix. Thats why code requires GFCI protection for wet/damp areas like kitchens, bathrooms and outdoors. When the risk potential increases the level of protection required increases. Our tanks are definitely wet locations and require increased protection. Given the nature of the system (electrical components immersed in the liquid medium) it can be argued that it requires greater protection than just a GFCI. Hence, the recommendation to utilize a grounding probe, to ensure that the GFCI will trip immediately upon the creation of a potentially hazardous situation.

[vaironman]

to follow up on scott's process of elimination test, if you have multiple powerstrips, then turn off all.

 

Turn on one by one powerstrip to find out which one contains the culprit and further down the process of elimination with plug-in one by one.

 

It usually is a powerhead is about to go bad as someone has mentioned.

Edited April 16, 2008 by vaironman

[BeltwayBandit]

 

It usually is a powerhead is about to go bad as someone has mentioned.

 

Heaters are also another 'usual suspect' with leaky current.

[yauger]

Heaters are also another 'usual suspect' with leaky current.

 

 

gotcha!

[SnowHeart]

As someone in the process of buying all the various thinks to setup a money pit... I mean saltwater tank... this thread is VERY helpful in explaining the ins and outs of grounding. Just ordered a GFCI outlet and a grounding probe. Now... if only I can install the outlet without killing myself.

[flowerseller]

Just ordered a GFCI outlet and a grounding probe. Now... if only I can install the outlet without killing myself.

Some chickens actually turn the breaker off before attempting to install a GFCI. I'm a chicken.

Make sure you put the load wires on load and line wires on line.

Doesn't have the same effect if you don't.

[SnowHeart]

Thanks flowerseller. I actually have installed ceiling fans in our new home so I'm not completely ignorant as to working with electricity (although, with one of the fans that turned into an extended project I did at one point forget to turn the power off and had an interesting arc of electricity and smell of ozone in the air... learned my lesson good). As long as the wires aren't all futzed up, I should be able to figure it out... If not, well, can always hire an electrician.

[YBeNormal]

I had a pump at one time that would trip the GFCI when I plugged it in but ONLY if I also had a grounding probe installed. Unplug the grounding probe and plug in the pump and everything appeared to be fine. Plug in the grounding probe and the GFCI would trip. Necessary or not, I will continue to use a grounding probe on my tank.

[BeltwayBandit]

Some chickens actually turn the breaker off before attempting to install a GFCI. I'm a chicken.

Make sure you put the load wires on load and line wires on line.

Doesn't have the same effect if you don't.

 

 

A GFCI, by operation, monitors current on the hot and neutral leg. By code, when they trip they open both legs, so you can't accidentally wire them backwards.

[flowerseller]

A GFCI, by operation, monitors current on the hot and neutral leg. By code, when they trip they open both legs, so you can't accidentally wire them backwards.

 

Never said you could wire them backwards, I implied you can wire them incorrectly.