GFCI Powerstrip?

[HM3105]

Has anyone come across a GFCI power strip where each outlet is an independent GFCI?

 

I keep thinking that if I use a standard DJ powerstrip with a GFCI outlet, if the GFCI ever trips, it'll shut down the entire tank.

 

Has anyone ever wired 4 GFCI's together so they'll act independent of one another, sort of like making a home made power strip?

 

I appreciate everyone's help.

 

Thank you

[joy13]

If you use a GFCI outlet it will shut down anything that is wired to and from that outlet. I have had that happen and thought it was the breaker but it was the GFCi that tripped when a heater went bad. When it tripped it took out part of the kitchen and the bedroom.

[HM3105]

If you use a GFCI outlet it will shut down anything that is wired to and from that outlet. I have had that happen and thought it was the breaker but it was the GFCi that tripped when a heater went bad. When it tripped it took out part of the kitchen and the bedroom.

 

Yes exactly, I don't want it to trip while I'm out of town or something and have the entire tank shut down. I was thinking about buying 4 GFCI's and wiring them so if one tripped it wouldn't shut down the tank. I've talked to a couple of electricians about how that might work and they said it shouldn't be an issue.

[jestep]

It would be easy to wire. A GFCI has line and load terminals. The load terminals are used when you want to put multiple outlets on the same GCFI. Otherwise, just ignore those and wire each one on the line terminals.

 

Finding and mounting the box for the outlets would be the hardest part IMO. Make sure that it and the outlets are properly grounded.

[AZDesertRat]

When I built my present 100G system I had a dedicated 20A GFCI circuit installed in addition to the existing 15A GFCI circuit. I split the load between the two separate circuits so I don't lose all pumping, lighting or heaters if one or the other pops.

[Gilligan]

The have plug-in GFCI 's if you want to have them plugged into a power-strip etc.

 

Like these.

http://www.petsandponds.com/en/aquarium-supplies/c5810/p17699445.html

[Mojado]

Why do you think you need GFCI? Serious question. If you aren't around a wet wall, finding a path to ground is pretty difficult (thus precluding your need for GFCI), assuming you don't mess with a ground probe that isn't submerged.

[Gilligan]

Why do you think you need GFCI? Serious question. If you aren't around a wet wall, finding a path to ground is pretty difficult (thus precluding your need for GFCI), assuming you don't mess with a ground probe that isn't submerged.

 

All appliances are tied to ground, like your aquarium accessories.

 

In North America, the ground is tied to the neutral back at the main electrical panel. They are in effect the same thing from an electrical standpoint. So even accessories with 2 bladed plugs will give a return to ground, especially if they are damaged. (nicked wires etc.)

 

3-pronged devices with exposed metal will have this metal at ground potential.

Touching this device with one arm and faulty equipment with your other arm will create a circuit, across your chest region. It only takes a few mA to put your heart into ventricular fibrillation.

 

Therefor it is generally good practice to work with one hand only when around exposed, or unknown to be safe electrical devices.

The idea is that accidental shocks will hopefully travel current through your arm and down your leg. Your chances of living are improved this way.

 

I have only been back in the hobby for a few months and already have had 2 failed devices that leaked electricity into my tank. The return pump in one of my Spec Vs ~40 volts and a Via Aqua 50watt heater ~5 volts.

 

Don't let anybody tell you that a few stray volts in your tank is normal. There are no devices that I have encountered that induce any significant potential or current in the tank.

 

Saltwater is highly conductive, salt molecules are half the size of water and may diminish the effectiveness of things like O-rings etc when deposits form on the sealing surfaces.

 

I find having a power bar separate from my light and timer is convenient, I just hit one switch to turn off everything that is in the water while doing maintenance.

 

It is very important to have at least one GFCI upstream of all your devices. Seperate ones if you want some partial fail-safe as mentioned above, to prevent all of your equipment from shutting down.

[HM3105]

Why do you think you need GFCI? Serious question. If you aren't around a wet wall, finding a path to ground is pretty difficult (thus precluding your need for GFCI), assuming you don't mess with a ground probe that isn't submerged.

 

I tend to think about things on a risk basis (I'm an accountant) so when I think about water mixing with electricity mixing with me, while the probability of something happening may be low, if it does happen the consequences are pretty high.

 

I appreciate everyone's comments on this, I think I am going to run an extra GFCI so only half the tank will shut down in the event of an accident.

[jestep]

 

I have only been back in the hobby for a few months and already have had 2 failed devices that leaked electricity into my tank. The return pump in one of my Spec Vs ~40 volts and a Via Aqua 50watt heater ~5 volts.

 

Don't let anybody tell you that a few stray volts in your tank is normal. There are no devices that I have encountered that induce any significant potential or current in the tank.

 

I don't disagree with you at all on the dangers of electricity. I was an electrician in the Navy and the stuff still scares the crap out of me. Not to mention that I get the s*** shocked out of me a few years ago by a faulty heater on a non GFCI and I grounded myself on my metal light fixture.

 

But, we've had several local members measuring ~40 - 50V being induced and not shorted into their tanks. Did equipment swaps and everything and were still getting huge voltages being induced. Testing with a good fluke multimeter.

 

The other thing I'm not quite clear on is the leaked voltage comments. It seems that a shorted piece of equipment would measure line voltage in the tank, anything else would be to be due to induction.

[Mojado]

 

Don't let anybody tell you that a few stray volts in your tank is normal. There are no devices that I have encountered that induce any significant potential or current in the tank.

I'm sure Faraday would disagree with you, little buddy.

[Mojado]

All appliances are tied to ground, like your aquarium accessories.

 

In North America, the ground is tied to the neutral back at the main electrical panel. They are in effect the same thing from an electrical standpoint. So even accessories with 2 bladed plugs will give a return to ground, especially if they are damaged. (nicked wires etc.)

 

3-pronged devices with exposed metal will have this metal at ground potential.

Touching this device with one arm and faulty equipment with your other arm will create a circuit, across your chest region. It only takes a few mA to put your heart into ventricular fibrillation.

 

Therefor it is generally good practice to work with one hand only when around exposed, or unknown to be safe electrical devices.

The idea is that accidental shocks will hopefully travel current through your arm and down your leg. Your chances of living are improved this way.

 

I have only been back in the hobby for a few months and already have had 2 failed devices that leaked electricity into my tank. The return pump in one of my Spec Vs ~40 volts and a Via Aqua 50watt heater ~5 volts.

 

Don't let anybody tell you that a few stray volts in your tank is normal. There are no devices that I have encountered that induce any significant potential or current in the tank.

 

Saltwater is highly conductive, salt molecules are half the size of water and may diminish the effectiveness of things like O-rings etc when deposits form on the sealing surfaces.

 

I find having a power bar separate from my light and timer is convenient, I just hit one switch to turn off everything that is in the water while doing maintenance.

 

It is very important to have at least one GFCI upstream of all your devices. Seperate ones if you want some partial fail-safe as mentioned above, to prevent all of your equipment from shutting down.

The reason GFCIs are used historically around wet walls or outside is that these places give you an easy path to ground (wet walls thru plumbing) and thus raise your risk of electrocution. It is actually pretty difficult to to get access to ground elsewhere in a home because of wood flooring, carpet, etc. Even concrete is a poor conductor. With concrete, you experience a shock, but nothing catastrophic.

[jestep]

The reason GFCIs are used historically around wet walls or outside is that these places give you an easy path to ground (wet walls thru plumbing) and thus raise your risk of electrocution. It is actually pretty difficult to to get access to ground elsewhere in a home because of wood flooring, carpet, etc. Even concrete is a poor conductor. With concrete, you experience a shock, but nothing catastrophic.

 

That's what happened with my heater. I felt a tingle a few times but didn't think anything of it, so it was fully shorted for a good year or two before I finally replaced my light with a hanging metal fixture. Figured it out quickly and painfully after that.

[Mojado]

I don't disagree with you at all on the dangers of electricity. I was an electrician in the Navy and the stuff still scares the crap out of me. Not to mention that I get the s*** shocked out of me a few years ago by a faulty heater on a non GFCI and I grounded myself on my metal light fixture.

 

But, we've had several local members measuring ~40 - 50V being induced and not shorted into their tanks. Did equipment swaps and everything and were still getting huge voltages being induced. Testing with a good fluke multimeter.

 

The other thing I'm not quite clear on is the leaked voltage comments. It seems that a shorted piece of equipment would measure line voltage in the tank, anything else would be to be due to induction.

 

Well, it depends on where the short was. If it is midway thru motor windings for a submerged pump, you'd get the water at a 60Vac. But most voltage you find in a tank is induced. Your tank is essentially a capacitor with respect to ground, a very, very small one at that. So the energy stored in the water from induced voltage is very, very small. I had someone measure it with a capacitance meter here on this forum and it measured in the picofarads (iirc).

[Mojado]

That's what happened with my heater. I felt a tingle a few times but didn't think anything of it, so it was fully shorted for a good year or two before I finally replaced my light with a hanging metal fixture. Figured it out quickly and painfully after that.

 

Ouch! Yeah, loads with metal casings have three prongs because the metal casing no longer provides isolation from the crap inside that housing. But this only protects you from being energized from crap *inside* that housing.

[Gilligan]

The reason GFCIs are used historically around wet walls or outside is that these places give you an easy path to ground (wet walls thru plumbing) and thus raise your risk of electrocution. It is actually pretty difficult to to get access to ground elsewhere in a home because of wood flooring, carpet, etc. Even concrete is a poor conductor. With concrete, you experience a shock, but nothing catastrophic.

This seems reckless, you missed the part where I mentioned that a few mA (about 30mA)across the right muscle will drop you dead. Not even a tingle.

120 VAC is particularly good at stopping your heart. (60 Hz)

 

Death has been documented to occur at 32 volts.

 

A member of the Navy was also documented killing himself with a multi-meter. He did that thing that everyone tries, to see how much resistance he could measure between his two hands. He then decided to pierce his thumbs with the probes to see how much less resistance there would be.

[Gilligan]

I'm sure Faraday would disagree with you, little buddy.

 

 

First, what are you trying to say?, second, we should learn the difference between standing in a shielded birdcage and sticking your arm into water with live wires.

 

This is a sticky subject that am simply am not going to argue on the internet about.

 

I have a virtually identical tank that I am able to do comparisons with. The voltages induced were maybe 1/10th of a volt.

That is why I worded my sentence that way, this would be about all you would expect and IMO is not significant.

 

Also I had 2 faulty devices in the tank at the same time, two live and two neutral, separated by a resistor, (saltwater) The voltage would measure different depending on the proximity of the devices to each other and the specific gravity of the water.

This takes some moderately heavy math to figure out on paper, it's not as simple as reading 120v in a tank. The tank itself has become a device, you are only measuring the voltage at one part of the circuit.

 

Maybe you care to explain how the fish instantly changed behavior with the removal of the faulty devices. I mean according to you a fish couldn't possibly be grounded!

 

My Agilent DMM is probably much more accurate then your blue-collar Fluke, when in doubt I have 100MHz 2 channel Tektronix scope I can rely on. However I only needed my $30 toolbox DMM to find this simple fault.

 

While I am not an electrician, I do have a Certificate of Mastery in Electronics and Circuits 6.002x from the Massachusetts Institute of Technology (97%) and I am a Community Teachers Assistant for the 6002.x online course.

 

One thing I learned there, is that I know absolutely nothing about electronics.

 

So I am hesitant to offer electronic advice, except when it comes to obvious safety concerns.

[jestep]

 

120 VAC is particularly good at stopping your heart. (60 Hz)

 

I always cringe when people are apathetic towards electricity. I've heard that "it's only 120" so many times it's pretty horrifying...

 

The most dangerous electricity we ever encounter just happens to be 120V/60Hz, the frequency will cause loss of muscle control, it creates enough current to stop a heart a hundred times over, but there's not enough current to blow someone off where they contact it at.

[Mojado]

This seems reckless, you missed the part where I mentioned that a few mA (about 30mA)across the right muscle will drop you dead. Not even a tingle.

120 VAC is particularly good at stopping your heart. (60 Hz)

 

Death has been documented to occur at 32 volts.

 

A member of the Navy was also documented killing himself with a multi-meter. He did that thing that everyone tries, to see how much resistance he could measure between his two hands. He then decided to pierce his thumbs with the probes to see how much less resistance there would be.

It is really 100-200mA for death.

Source: https://www.osha.gov/SLTC/etools/construction/electrical_incidents/eleccurrent.html

 

Internal human resistance, past the skin, is on the low side 300 ohms.

Source: http://van.physics.illinois.edu/qa/listing.php?id=6793

 

So, a little Al Jarreau (Algebra) and you get wet skin resistance of 350 ohms, dry skin of 50k ohms (300 ohms of internal human resistance << 50kohms, I ignored it).

 

So, to get shocked, you'd have:

 

120V----wet skin (350ohms)-----internal resistance (300 ohms)-----dry skin (50kohms)-------GND

 

This gives you a current of 2.4mA. This falls under the 5mA mark which results in "Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries." That's why Jestep is still with us.

 

So that's the worst realistic case, as long as you don't do anything too stupid. And that's when you touch a grounded object while touching a hot object with a wet hand. Most times, you are isolated from ground, electrically.

 

So, don't touch metal objects that are potentially grounded when you are messing with your tank. Electricity should be respected through understanding of its physics, not feared with stories of sailors killing themselves with multimeters. If you still feel that GFCI is warranted, by all means do so.. .just don't do it out of fear or ignorance. Also understand that unnoticed nuisance trips can have a catastrophic consequence to your tank.

 

Now, GFCI in the bathroom and outside are a different story. There I can see myself being exposed to 120Vac with two wet hands and a path to ground.

 

Happy Reefing.

[Mojado]

First, what are you trying to say?, second, we should learn the difference between standing in a shielded birdcage and sticking your arm into water with live wires.

I'm talking about Faraday's law of induction, not a Faraday cage.

[Gilligan]

It is really 100-200mA for death.

Source: https://www.osha.gov/SLTC/etools/construction/electrical_incidents/eleccurrent.html

 

Internal human resistance, past the skin, is on the low side 300 ohms.

Source: http://van.physics.illinois.edu/qa/listing.php?id=6793

 

So, a little Al Jarreau (Algebra) and you get wet skin resistance of 350 ohms, dry skin of 50k ohms (300 ohms of internal human resistance << 50kohms, I ignored it).

 

So, to get shocked, you'd have:

 

120V----wet skin (350ohms)-----internal resistance (300 ohms)-----dry skin (50kohms)-------GND

 

This gives you a current of 2.4mA. This falls under the 5mA mark which results in "Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries." That's why Jestep is still with us.

 

So that's the worst realistic case, as long as you don't do anything too stupid. And that's when you touch a grounded object while touching a hot object with a wet hand. Most times, you are isolated from ground, electrically.

 

So, don't touch metal objects that are potentially grounded when you are messing with your tank. Electricity should be respected through understanding of its physics, not feared with stories of sailors killing themselves with multimeters. If you still feel that GFCI is warranted, by all means do so.. .just don't do it out of fear or ignorance. Also understand that unnoticed nuisance trips can have a catastrophic consequence to your tank.

 

Now, GFCI in the bathroom and outside are a different story. There I can see myself being exposed to 120Vac with two wet hands and a path to ground.

 

Happy Reefing.

 

OK so the first link of yours I checked says, and I quote:

"Extreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible."

This is at 17mA, half the amount of current that I mentioned.

 

A 300 ohm resistor is about as low as the lowest resistors I have in my parts box. Low resistance means current will flow easily.

300 ohms is a virtual dead short when you compare to "high" value resistors of one million ohms or more.

 

I said that it takes around 30mA across the heart to cause fibrillation and it does. Your link is basically saying you might not die, as most of current may travel your leg(s)

 

Your link states "Ventricular fibrillation (uneven, uncoordinated pumping of the heart.) Muscular contraction and nerve damage begins to occur. Death is likely."

This means that you don't have to give a path directly across your heart, it can kill you with just your hand and leg.

 

Do you have any concept of how little difference there is between 30mA and 100mA when you are talking about electrical outlets that deliver 15,000mA to 20,000mA?

 

By the way 120VAC / 300 ohms is 0.4 = 400ma!

 

I can google for an answer I want to hear too, look see "A domestic power supply voltage (110 or 230 V), 50 or 60 Hz alternating current (AC) through the chest for a fraction of a second may induce ventricular fibrillation at currents as low as 30 mA.^[5] With direct current (DC), 300 to 500 mA is required"

http://en.wikipedia.org/wiki/Electric_shock#Ventricular_fibrillation

 

Why is your kitchen and bathroom more dangerous then another rooms?

Because of the close proximity of the electrical outlet to the grounded tank of water you put your hands in. Sound familiar?

 

As far as all of this "don't do anything too stupid" and "just don't do it out of fear or ignorance", well guess what most of the population is "ignorant" about electricity, including yourself. Ignorant does not have to be a derogatory statement, it's just that people intentionally choose to ignore things, or just don't care.

 

The idea of electrical safety is to make it safe for all.

A six year old kid is not going to listen or always remember "So, don't touch metal objects that are potentially grounded when you are messing with your tank."

 

Anyhow I don't care that much about what you do, it's other people reading your posts, along with reading about stray voltage on aquarium websites, that is concerning.

 

With respect.

[Mojado]

By the way 120VAC / 300 ohms is 0.4 = 400ma!

 

You're not understanding the concept. Why are you dividing by 300 ohms? That's the internal resistance of the human body. You still have to get thru the skin, little buddy.

 

Oh, and 300 ohms is not a "virtual dead short". Wow! Your average 60W light bulb has less resistance than a 300 ohm resistor...and you don't short out your house when you turn on your light switch. That is not a "virtual dead short".

 

uA across the heart will kill you, but unless you open someone's chest up and run probes across the heart, you don't have to worry about. You look at the conditions that apply to the situation we are talking about. This is what I did above. My calculation of less than 5ma is valid and consistent to what we're talking about.

[Gilligan]

You're not understanding the concept. Why are you dividing by 300 ohms? That's the internal resistance of the human body. You still have to get thru the skin, little buddy.

 

Oh, and 300 ohms is not a "virtual dead short". Wow! Your average 60W light bulb has less resistance than a 300 ohm resistor...and you don't short out your house when you turn on your light switch. That is not a "virtual dead short".

 

uA across the heart will kill you, but unless you open someone's chest up and run probes across the heart, you don't have to worry about. You look at the conditions that apply to the situation we are talking about. This is what I did above. My calculation of less than 5ma is valid and consistent to what we're talking about.

 

I am using ohms law based on the 300 ohm number you quoted, remember chances are your hands will be wet in the tank.

A 60w incandesent light-bulb cannot be measures cold. It's resistance changes as it heats up. This is why your light bulb usually burns out when you first turn it on. Fuses and breakers have a small delay to deal with this. They even make slo-blo fuses to not pop right away because of devices like this.

This is why we use dim-bulb testers when experimenting with electronics.

So which resistance are you using to your advantage again?

 

You don't have to open someones chest to send current through the heart. Hand to hand voltage potential will suffice. Even hand to foot has no guarantee that it won't cross the heart. Picture how sparks or lightning travels.

 

Everybody is different composition-ally. Your arm is a resistor, therefore the diameter and length are directly tied to resistance. Men are generally more conductive then women.

 

The situation you stating is more comparable to a 50 watt bulb. I can't fathom how you regard that kind of power as safe.

 

Any how I feel I have stated a reasonable case for safety.

Feel free take quotes of me out of context in order to get the last word. I can take it.