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GFCI outlet + aquariums

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I was wondering if any of you have used GFCI outlets with your aquariums.  An aquarium seems to be the definition of why you would want a GFCI outlet, several things plugging into a wall outlet that are above an in the water, and then you stick your arm in the water frequently without even thinking twice about it.  I've never seen any home user have a GFCI outlet on their aquarium, nor have I had one for the past 30-40 years of aquariums.

I'm debating about swapping out the outlet behind my aquarium with a GFCI outlet, and I was wondering if anyone else has done that?

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I have not done this for the aquarium, but a GFCI outlet is always a good idea anywhere water is involved.

Having experienced a current leak on the outdoor pond, all of my outdoor fixtures are GFCI protected.

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I can’t imagine having an aquarium not plugged in to a GCFI outlet and not having grounding probes in it.

Both are important.

you don’t necessarily need to have the outlet changed. You can opt for a GFCI cord that plug into your exiting outlet and plugging the aquarium in to the GFCI.


The GFCI will constantly monitor the electricity going out the hot and returning through the neutral. If as little as 6 milliamps is detected not coming back thenit is going to ground by another route.  That route may be through your body if your arm is in the tank.  The GFCI is designed to trip off within a tenth of a second.


so why do I put a ground probe in my tanks?  To provide an alternative route to ground for any voltage potential in the tank.  This will allow the GCFI to trip before I put my arm in the tank and complete the route to ground….


And, when I do my first Saturday of the month cleaning, I trip the GFCI test button to make sure it trips and everything shuts off and then reset it.  This is important both in letting you know it is working and to provide movement to the trip mechanism to prevent it from fusing in the energized position…


And I have all devices with wires entering the tank on a single power strip so I can shut it off before sticking my arm in the tank…. And my heaters are controlled by inkbird controllers to minimize the time those cords are energized…


I am a former Paramedic, and was formerly ABYC certified Marine electrician and taught a  boat electrical course at Wooden Boat School in Brooklin Maine.


If you think you dont need a GFCI outlet or ground plug or to turn off power before putting your hands in, well,  good on you….  Just remember Murphy gets bored and is a tricky fella..

Edited by Pepere
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I have a. Titanium grounding probe which is attached by suction cup to the back glass near the aquarium heater.

They are as cheap as 12.00,  GFCI outlet is around 20.00. Cheap insurance..

Edited by Pepere
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Yes. That is the exact unit I use.


it is important to ensure the outlet you plug it into truly has a ground and the ground is connected.


in homes where prior homeowners have fiddled with the wiring strange things can be done sometimes..

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Also, I'm wondering how a GFCI would interact with a KASA power strip.  It seems like it isn't recommended: https://www.tp-link.com/us/support/faq/2441/


Q: Can a HS300 be plugged into a power strip, another surge protector or an uninterruptible power supply (UPS)?

A:  No. The HS300 power strip must be directly plugged into a grounded outlet to work.


Q: Can I use a surge protector with a GFCI (ground fault circuit interrupter) outlet?

A: No. Incompatible electronics within the GFCI and the surge protector can cause either to trip. GFCI outlets are placed in potentially wet locations such as sinks, bathrooms and garages. Surge protectors should be used in wet or potentially wet locations.


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On 8/20/2023 at 8:59 PM, Galabar said:

Maybe a dumb question, but does the grounding probe plug into a non-GFCI outlet or the same GFCI outlet as the rest of the tank?

The grounding probe simply needs to be connected to a good ground.  It can be the GFCI outlet or another one.  When a GFCI trips it cuts of the power to the hot conducter but does not break continuity to the ground.

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On 8/20/2023 at 9:09 PM, Galabar said:

Also, I'm wondering how a GFCI would interact with a KASA power strip. 

It appears Kasa is recommending  not to use them together.  I use standard power strips without surge protection.

I much prefer GFCI protection over surge protection for aquarium components.

On 8/20/2023 at 9:15 PM, Galabar said:

One more thing, besides the KASA issue, would this work (in an office with fish tanks):


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GFCI outlets can be subject to nuisance trips due to combination of capacitance and inductance and also dc voltage flowing on the line bein misidentified.  

conductors can carry both dc current and AC at the same time.


I had a tenant with a Tesla that I had an outside 20 amp 120 outlet installed for.  It would allow her to top up mileage overnight for her daily use.  Recharges the car at rate of 3-4 miles per hour of charge.  The GFCI was nuisance tripping so we changed the outlet same brand with similar trip frequency.


testing her car there was no discernible ground fault acroos either terminal with the ground.


Changing to a different brand GFCI resolved it.  My next course of action would have been to wrap feed wire before outlet in a ferrite coil…

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Remember, you don't need to use a GFCI on the actual outlet you plug your aquarium stuff into. It's enough to have a single GFCI in the circuit AHEAD of the aquarium plugs. For my "fish office" I have wiring coming from the breaker box in the garage to the front doorbell, and then the first outlet in my office. That one I put a GFCI on, and everything else after it in the circuit in my office and the kid's room (same line) is then protected.

I'd also call out that everyone should be doing this. It's crazy to me that people don't. There's a reason that in many places GFCI is required in bathrooms and outside. Water and electricity can kill, and no hobby is worth that.

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On 8/21/2023 at 2:19 PM, Maximus said:

don't know how the behavior will change if you use a plug-in vs. a normal outlet like I did. It might not apply to downstream outlets in the same way

A plug in GFCI will not protect downstream receptacles.


a wired in GFCI outlet canbe wired either to protect downstream receptacles or not.

if you test a GFCI receptacle and trip it and downstream receptacles have power, they are not protected.

Not all GFCI outlets will have a connected ground either…. They can be used in older houses for romex that does not have a ground conducter and then legally you can replace the two slot outlets downstream with grounded outelts so long as a little sticker saying GFCI lrotected outlet, no equipment ground is placed on the outlet plate.  Those stickers do not stay put for many years..,

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On 8/22/2023 at 7:01 PM, Pepere said:

This particular unit will trip off when the power goes out.  You will need to manually reset it after the power comes back on.

In our case, that is a deal breaker. When we are away from home, we need power to be restored automatically. Assuming we find one that does this, I have questions of my own.

We have small UPS' on our aquarium equipment, currently connected to non-gfci outlets. Some equipment are connected to wifi or zwave controllers, that are then plugged into the battery backup on the ups.

Will it be sufficient to plug the ups into a gfci strip or plug? Or...

wall (non-gfci) outlet - ups - controller - gfci plug - aquarium appliance


wall (non-gfci) outlet - ups - gfci plug - controller - aquarium appliance


Edited by HelplessNewbie
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On 8/22/2023 at 7:38 PM, HelplessNewbie said:

Will it be sufficient to plug the ups into a gfci strip or plug? 

Imagine if you plug the UPS into the GFCI.  And for some reason the GFCI trips.  The UPS then makes electricity off of your stored battery power…  what then will protect you from a ground fault?  It has to have GFCI after the UPS.   And it has to be a GFCI device that is rated to work with the UPS or inverter.  You need to check the documentation with the inverter UPS unit.    There are GFCI outlets that do not trip properly with certain inverters… and a UPS is in essence a battery, a battery charger, an inverter, and a relay…

I am not sure if all plug in GFCI units are designed to trip when power is lost.  I know actual wired in GFCI outlets do not do this.  

It is possible this is a recent code requirement.  I was certified and active as ABYC marine electrician about 15 years ago and do not keep up on changes in the residential code.


In my circumstance, I have a wired in GFCI outlet at the first outlet in a series that protects all downstream outlets.  I do not run an uninterruptible power supply.  I live on a main road in my town and outages are rare and prioritized for repair quickly as it is near a lot of businesses and residential units…. By and large the power company prioritizes repairs that turn the power back on to a lot of customers at once…  Most outages I see last less than an hour.


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