This could be the next major headline in the nation’s newspapers, and it could be you that dies.
I’m talking about placing your hands in your aquarium and getting electrocuted. All because you failed to install $15 worth of equipment. Not only you, but the $1,000 you spent on livestock over the past year would be fried too. Besides laying dead next to your tank, your aquarium will turn into black soup within hours. Both you and your aquarium will smell pretty bad.
Aquarium water needs to be grounded. Saltwater is about as conductive as copper wires, and any stray voltage needs to be sent to ground where it will do no harm. Stray voltages are generated from lots of things. When a powerhead or pump motor spins it creates a magnetic field that induces AC voltages in the water. Likewise, ballasts that drive your light bulbs located within a few feet of the tank generate tremendous amounts of stray voltage. I’ve measured stray voltages as high as 46 volts in ungrounded aquariums. While this alone won’t kill you, you will get quite a jolt the minute you touch the water. Lots of research has been done that indicates stray voltages cause LLE (Lateral Line Erosion) in marine fishes, Hole-in-the-Head disease in fresh water fish, and bleach spots in SPS corals.
While stray voltages won’t kill you, equipment malfunctions will. Take any standard glass aquarium heater. Due to its age (are you still using that heater you bought in 1998?) or impacts over its lifetime, or a myriad of other failure mechanisms, heaters will develop hairline cracks in their glass casing. When this happens, minute drops of saltwater is forced into the heater. This is because even at a depth of 6-inches, water exerts pressure on an air-filled heater, forcing water through the tiny crack. Eventually, enough moisture gets in where the hot side of the AC line is conducting current to the neutral side. A ground probe won’t save you. While some current will be diverted to ground, current is freely flowing inside the heater, perhaps several amps and charging the surrounding water. When you put your hand in the tank, you present a better ground path and the current goes through you. Your spouse will either find you dead or dying in front of your precious aquarium.
You need to eliminate yourself from ever being part of the ground loop, and the easiest and cheapest way to do this is to install a GFCI (Ground Fault Circuit Interrupt) outlet. These sell for about $10 at Home Depot. You can buy the kind that replaces your existing wall outlet or ones that are built-in to an extension cord. Either one works. The point is,
An aquarium ground probe won’t protect you from electrocution. You must have BOTH a ground probe and a GFCI.
Here’s a real life story. A few months ago I woke up to find one of my tanks, a 20 gallon setup, dark and quiet. It had lost power. I checked the powerstrip and the pilot light was off but it was plugged into the wall. I quickly realized that the GFCI Outlet had tripped. I pushed the reset button on the outlet to restore power and it wouldn’t stay in. I figured the GFCI outlet had crapped out. I ran an extension cord over to the tank from a regular (non-GFCI) outlet and plugged the powerstrip in. Viola! The lights came on, the pumps started up, and everything was fine.
Being an electrical engineer, I was very curious about the defective GFCI outlet. I plugged everything back in to the GFCI and then started unplugging each cord one at a time. When I got to a Maxi-Jet 1200, the GFCI stopped tripping. I plugged the Maxi-Jet back in and sure enough, it tripped again and killed the power. I grabbed my voltmeter and put one probe in the water and the other to ground. I plugged the tank back in and read 114 volts. Holy shit- If I had put my hands in the tank, I wouldn’t be writing this at all. Or maybe doing so from the intensive care ward. No doubt that I would have been electrocuted if it wasn’t for that GFCI outlet.
I figure that the powerhead must have gotten a crack in its epoxy coating, or perhaps it was there from day 1 and it took 6 months for seawater to slowly leak in. Whatever the reason, the ground probe alone would not have prevented my demise. As long as the current flow through the ground probe stays below 15 amps, the service panel breaker in your house will never trip. And all it takes is 100 milliamps (1/10th of an amp) to stop your heart. No matter what the odds, is your life worth a $20 powerhead?
I don’t know how else to convince you how important this is to do. You need to do it TODAY. If you don’t give a shit about yourself, don’t take a risk electrocuting one of your kids or your spouse. Install a GFCI and a ground probe on EVERY tank in your house no matter how small. If you don’t, the next time you put your hands in your tank may be the last.
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By: Aquarist Found Dead - Saltwater and Reef Aquarium Forums - Reef Builders Forum on November 6, 2007
at 3:22 pm
UH WOW… well i do not want to place myself or my family in the line of danger when it is ultimately up to me and how I have the tanks set-up!! Furthermore..I usually buy used equipment… I have thought of the electricity side before…but not to the extent of placing the outlet you mentioned and the grounding of the tank????
so…question… how does one Ground a Tank?
I can do the electrical outlet… but not sure on how to ground a tank.. a response would be great!!!!
By: reyes flores on February 12, 2008
at 1:13 pm
You can buy ground probes for around $10US in just about any fish store. One end goes in the tank, the other connects to the ground lug on any outlet.
Most all ground probes are made of titanium so they will never rust.
By: joejaworski on February 12, 2008
at 1:57 pm
Ummm… I’ve had 2-3 heaters go bad in the tank and I always found out by touching the water. The electricity wasn’t a big jolt… rather a vaguely unpleasant tingle. Now I have fresh water tanks and the heaters were not all that large. I found your article while searching to see what stray electricity would do to my fish. They’ve never seemed distressed or harmed when I found and replaced broken heaters.
Is the risk life threatening because you have salt water tanks? Was it negligible because my heaters were small and the water was fresh? Will the voltage damage my fish?
I’m fixing to get a 180 gal tank with the accompanying larger electrical devices to run it. So I’m a bit concerned about this now.
It’s my understanding that a GFCI outlet shuts the current off only after the current has run thru a person’s body. Like, it’s can’t prevent you from being shocked, but it will shut it off to stop the voltage and minimize the damage. Is this right?
How can I stop a broken heater from damaging my fish (if indeed, it will do that)? How can I find out that it is broken without touching the water? In my recent experiences with broken heaters the light, Emperor pump, and heater were all plugged into an outlet strip (with a fuse) and everything else on the strip continued to work. I had to unplug things and keep testing to see which one was putting electricity in the water. Is there a device to hang on the tank that will monitor any stray electricity in the water?
By: TJ on March 27, 2008
at 1:30 pm
TJ,
Getting any electrical jolt is bad news for your heart. If you only got a small jolt from touching the water in a tank with a bad heater, you may have been wearing a pair of Nike’s (rubber soles). In bare feet, the shock would be much worse.
Stray voltage does pose health risks to your fish. LLE (lateral line disease) is caused by stray voltage. Excessive “spooking” (where fish dart around frequently as if they are scared) is caused by stray voltage. No one knows the long term effects of spooking, but anything that adds this much stress to your fish can’t be good.
The risk is life threatening in both fresh and saltwater. Saltwater is worse, because it is 10 times more conductive.
How a GFCI outlet works is that it monitors power on the ground lug of the AC outlet. There should never be any power flowing to ground. If any voltage is detected on the ground lug, it is called a voltage fault. The GFCI outlet responds within 1/1000th of second when it detects a fault. This is so fast that you won’t feel a thing, but technically you are right- you do get shocked but it is so short it doesn’t hurt you. But GFCI’s won’t work unless the aquarium water is grounded. Hence, the reason for using a ground probe.
If you have a broken heater and the heater is plugged into a GFCI outlet AND the tank water has a ground probe in it, then the power will go out before you even put your hands in the tank. The GFCI is monitoring for faults 24/7, so as soon as the heater cracks or goes bad, it pops the outlet off.
A fuse, a power strip with a circuit breaker, or a surge-protected power strip doesn’t do anything because these devices don’t care whether the voltage returns to ground or through your hands and feet.
A simple way to check for stray voltage is to use a multimeter from Radio Shack. Set the meter to read AC voltage, then touch the black probe to the ground lug on an outlet and place the tip of the red probe into the water. If you have stray voltage, you will be able to measure it
By: joejaworski on March 27, 2008
at 5:05 pm
Thanks for the responses, Joe. Your blog entry raised my interest enough so that I’ve been reading other stuff on aquariums and electricity this afternoon. One person in a forum, said that a grounding probe without a GFCI will kill your fish. He said fish in a tank with electricity, are like birds on a high voltage wire. The current is all around them, but they don’t know it because they aren’t grounded. I.e., once you put a grounding probe in the tank, the fish are being shocked. That is, unless the GFCI shuts off the current. Thought I’d add this little bit of info that I discovered. I’m off to buy a GFCI extension cord and grounding probe tomorrow. Thanks for your taking time to post how this works.
By: TJ on March 27, 2008
at 6:24 pm
FYI, The “birds on the a power line” is not a good analogy because air does not conduct electricity like water.
By: joejaworski on March 28, 2008
at 6:00 am
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By: Alexwebmaster on March 3, 2009
at 6:41 am
Sir,
Nice article – I recently discovered my tank has 40 volts and purchased a ground probe. I understand the principle of a GFCI but my situation is different…
I have a large UPS system and all my aquarium stuff (everything) is plugged into this UPS. So a GFI on the wall wont help; circuit (GFI) will trip but the UPS will still provide power until batteries are dead.
Suggestions?
By: John on September 23, 2009
at 3:09 pm
Despite popular belief, a computer UPS does not have galvanic isolation from either ground or the neutral wire of the outlet. Both a GFCI outlet and a ground probe would work the same with a UPS.
However, if the AC power is out and the tank is running on batteries, the GFCI is not in the loop anymore and there is the possibility of shock (especially if the GFCI tripped in the first place and the rest of your house has power.).
By: joejaworski on September 23, 2009
at 4:32 pm