Aquarium and electrical safety

[Freenow54]

I keep apex and eb832s away from tank but the 20 amp breaker is not dedicated just to tank, but that is what the basement circuit is on. I’ve definitely used 15 amp drop cords on 20 amp breakers before?

bad practice if large load for extended time .Lots of heat generated to my mind

 

[blackgate]

According to eb832, tank currently draws between 300 to 600 watts. I can certainly change out breaker and main outlet but it would seem to still make sense to keep them 20 amp, no?

 

[Reefering1]

According to eb832, tank currently draws between 300 to 600 watts. I can certainly change out breaker and main outlet but it would seem to still make sense to keep them 20 amp, no?

If it came with 20a breaker, keep it 20a.

 

[Randy Holmes-Farley Verified Community Expert]

There is no “simple” or straightforward answer, and the explanation will probably confuse some people. Instead of giving direct advice, let me just try to explain how inverter (UPS) and portable-generator outputs differ from your utility power. Sorry, this will be long and a bit technical, there is no way around it.

Most consumer UPS units and small generators have a floating neutral.

That means the neutral isn’t tied to earth ground. Its only reference is the hot. In other words, the only place current can flow (in theory) is between the inverter’s HOT and its own derived NEUTRAL.

Think of a battery. The only place current can flow is between its two terminals. If you touch only the positive terminal, even standing in a puddle, nothing happens. A floating inverter output is basically the same idea (ignoring AC vs. DC). Its two output terminals can only (in theory) pass current between each other.

With your utility supply, the NEUTRAL is bonded (electrically connected) to EARTH GROUND at your service panel. So if you touch utility HOT while you’re grounded, current will flow from HOT through you to GROUND, partly or fully bypassing the neutral. That’s the fault path a GFCI is designed to detect.

With a floating source, touching HOT while grounded doesn’t create that path. There is no path to ground. So (in theory) you don’t get shocked.

---

“Hey Bean! That sounds great, my UPS or generator can’t shock me!”
No. It can absolutely shock you!!
If you grab HOT and NEUTRAL from the floating source, you will get shocked. You just become the load.

In a bonded system you would also get shocked if you grab hot and neutral. The difference is crucial to understand: if you are grounded, a GFCI would trip because some of the current leaks to ground. In a floating system, there is no neutral-to-ground reference at all, so the GFCI has nothing to compare and will not trip.

If you are grounded is a very important caveat. In a bonded system if you are insulated and touch hot and neutral, you also become the load and the GFCI can't help you.

So on one hand, the floating system can be called “safer” because the typical line-to-ground fault doesn’t exist. On the other hand, there is zero protection for a line-to-neutral fault, and the system is not GFCI protectable.

I leave it to you to decide if it is safer or more dangerous overall. I think many who understand these systems would argue that line-to-ground faults are more common (frayed hot wire, hand in water, feet on floor... or face against faulting fixture, hand in grounded tank) and these faults are far less likely in a floating system. They would likely point out that in a floating system, just as in a bonded system, the GFCI offers minimal protection for line-to-neutral contact and only helps in the line-to-neutral scenario if the person is also grounded.

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“Hey Bean! What is all this ‘in theory’ nonsense?”

We say “in theory” because depending on how the source is built, some tiny amount of current can leak to ground — transistor base drive, generator excitation, internal filtering, other complex faults, etc. So even in a floating system chances of ground fault are not mathematically zero and from a safety perspective you should not treat the floating output any differently.

---

"Hey Bean! What about using them anyway for when the UPS or power station is delivering mains power?"

Well that depends on how your UPS or power center is built. You MUST check the documentation. Many UPS system will pass neutral through (bonded) when on Mains Power and switch to floating when on battery. So on mains power, the GFCI behaves as expected,

However many power centers like Jakery, or Bluetti or EcoFlow derive their outputs from their inverters 100% of the time, so they are always floating.



They only care about the imbalance between hot and neutral. That part is correct.

But the key point (and why this gets confusing) is that a downstream GFCI can only see an imbalance if the system has a neutral-to-ground reference. On a bonded system, a line-to-ground fault creates that imbalance and the GFCI trips. On a floating UPS/generator output, there is no reference, so there’s no imbalance, so it won't typically trip. But back to the "in theory" part, as depending on how the device is built, there could be enough leakage current for it to trip.

The end...

Excellent description that makes perfect sense and points out the risks of battery backup. Thanks so much for the detailed response.

It also points out why using all low voltage devices on a battery backup is a huge plus.

I think that point needs to be made more strongly across reef2reef.

 

[DexterKarin]

Excellent description that makes perfect sense and points out the risks of battery backup. Thanks so much for the detailed response.

It also points out why using all low voltage devices on a battery backup is a huge plus.

I think that point needs to be made more strongly across reef2reef.

To this point, and going back to electrical kindergarten, how do you figure out what is low voltage and what is high? Is this something that is spected for each piece of equipment. What am I looking for? And what is the number associated with low and what is high?

Sorry, my head spins with this.

 

[Paul B]

In the electrical trade low voltage is anything under 100 volts, But in the hobby low voltage is normally about 24 volts or lower and usually also DC.

This low voltage won't shock you and DC won't induce any electricity in your tank water. Everything except heaters can be bought low voltage.

I don't know of a low voltage heater yet.

 

[RobertK]

If you have a ground probe plugged into a GFCI outlet, and the GFCI outlet trips off, is the ground probe still grounded?

It depends on whether the GFI itself is grounded. If it is on a 2 wire system, with no ground, then no, it is not grounded. But I'm sure Bean could add a lot to that.

Thank you. I should have asked "If you have a ground probe plugged into a properly grounded GFCI outlet..."

Also, about arc faults, I had an electrician out to the house yesterday to install another GFCI outlet on a separate circuit for the aquarium for redundancy. I asked him about installing arc fault breakers and he recommended against it. He said they are required on new construction but they trip frequently and are a nuisance.

 

[Freenow54]

No one asked so I will considering the fact that most of our Equipment is two prong how does the GFI protect us? Also what is the function of the wider spade on some.

 

[Freenow54]

Thank you. I should have asked "If you have a ground probe plugged into a properly grounded GFCI outlet..."

Also, about arc faults, I had an electrician out to the house yesterday to install another GFCI outlet on a separate circuit for the aquarium for redundancy. I asked him about installing arc fault breakers and he recommended against it. He said they are required on new construction but they trip frequently and are a nuisance.

If they are functioning against unseen issues in the wiring that can cause fires , than how can they be called a nuisance ? Aluminium wiring comes to mind as one example. Question for the two gurus

 

[Freenow54]

If it came with 20a breaker, keep it 20a.

If my mind is in the game the breaker only protects the line. If the wiring is the proper Gauge for the entire circuit than that's what it should be. I only asked if the circuit was dedicated to the Aquarium.

 

[Freenow54]

I keep apex and eb832s away from tank but the 20 amp breaker is not dedicated just to tank, but that is what the basement circuit is on. I’ve definitely used 15 amp drop cords on 20 amp breakers before?

Risky due to the size ie amperage draw of the load I would think

 

[Paul B]

Thank you. I should have asked "If you have a ground probe plugged into a properly grounded GFCI outlet..."

Yes, the ground will still be connected.

Thank you. I should have asked "If you have a ground probe plugged into a properly grounded GFCI outlet..."

Also, about arc faults, I had an electrician out to the house yesterday to install another GFCI outlet on a separate circuit for the aquarium for redundancy. I asked him about installing arc fault breakers and he recommended against it. He said they are required on new construction but they trip frequently and are a nuisance.

I don't think you need an arc fault. I never use them.

Also what is the function of the wider spade on some.

Thats a polarized plug. It is so you don't plug the thing in with the improper polarity. Some devices, if they fail, will have the shell or body of the device connected to the neutral side of the circuit so it is safer as the neutral is connected to the ground in your panel. You don't want the outer shell of the appliance to ever be connected to the hot wire in a circuit. That polarized plug prevents that.

If you have an older two prong plug like for Christmas lights or something that is plastic and not much shock hazzard, it doesn't matter which way the thing is plugged in. But for like a blender, refrigerator, stove or metal power tool, the manufacturer wants you to connect it to a polarized outlet so that larger prong will not allow you to plug it in backwards.

Don't try to defeat that by grinding down that plug so it fits anywhere. (Like I often do for Christmas lights)

 

[Paul B]

No one asked so I will considering the fact that most of our Equipment is two prong how does the GFI protect us?

You just have to move to the US.

 

[BeanAnimal]

No one asked so I will considering the fact that most of our Equipment is two prong how does the GFI protect us? Also what is the function of the wider spade on some.

The GCI looks for an imbalance of current between hot and neutral. Even though it is called a "Ground Fault Circuit Interrupter" it really has nothing to do with "ground". It doesn't know where current leaks, it just knows that all of the current sent out of the Hot terminal did not come back on the Neutral terminal, and when it detects that imbalance it trips.

If they are functioning against unseen issues in the wiring that can cause fires , than how can they be called a nuisance ? Aluminium wiring comes to mind as one example. Question for the two gurus

The "nuisance" is when they trip due to false positive. Large brushed AC motors (vacuum cleaners), ballasts, poorly filtered switch mode power supplies, and many other things that cause rhythmic frequency spikes can look like an arc fault to the AFCI.

 

[Paul B]

If they are functioning against unseen issues in the wiring that can cause fires , than how can they be called a nuisance ?

Nuisance tripping is when there is no real danger, like if the power company has a slight dip in their electric service, or if it is very damp, or if a heavy appliance turns on and there is a large current draw even on another circuit. Many things will trip a GFI. I don't use them on my outdoor outlets even though they are code. The people who write the code are not electricians.

 

[BeanAnimal]

You don't want the outer shell of the appliance to ever be connected to the hot wire in a circuit. That polarized plug prevents that.

Somebody forget to tell Leo Fender that...

Nothing like fingers on a guitar string and lips against a metal mic shield attached to a different amp with reverse polarity.

 

[Freenow54]

Yes, the ground will still be connected.


I don't think you need an arc fault. I never use them.


Thats a polarized plug. It is so you don't plug the thing in with the improper polarity. Some devices, if they fail, will have the shell or body of the device connected to the neutral side of the circuit so it is safer as the neutral is connected to the ground in your panel. You don't want the outer shell of the appliance to ever be connected to the hot wire in a circuit. That polarized plug prevents that.

If you have an older two prong plug like for Christmas lights or something that is plastic and not much shock hazzard, it doesn't matter which way the thing is plugged in. But for like a blender, refrigerator, stove or metal power tool, the manufacturer wants you to connect it to a polarized outlet so that larger prong will not allow you to plug it in backwards.

Don't try to defeat that by grinding down that plug so it fits anywhere. (Like I often do for Christmas lights)

Never I thought so But better to ask did not know about using the shell. As to outdoor Christmas lights I cut them off and use mar rets and what I call sap tape . So with that in mind how does the GFI protect you ?

 

[Freenow54]

Nuisance tripping is when there is no real danger, like if the power company has a slight dip in their electric service, or if it is very damp, or if a heavy appliance turns on and there is a large current draw even on another circuit. Many things will trip a GFI. I don't use them on my outdoor outlets even though they are code. The people who write the code are not electricians.

He was talking about ARC protectors so what about them ?

 

[Freenow54]

You just have to move to the US.

I come there quite often to teach Donny how to improve his short Golf Game. Besides it seems that the medical profession there want to replace all your parts to turn you into an obedient robot

 

[RobertK]

He was talking about ARC protectors so what about them ?

The electrician said they false trip frequently. He strongly advised against them. He said they only use them on new construction because that is the current building code, and he joked about taking them out after passing inspection.

He also thought that aquarium water pumps would likely trip them when they were cycled on and off - does anyone know if that is true?