Using ground probes in aquariums

[jasonrusso]

Why isn't absolutely necessary to plug the grounding probe into the GFCI?

It isn't necessary, but it's recommended. A circuit breaker lets 15 amps flow through the circuit, it doesn't care where it is going. A GFCI monitors what comes out of the power and what returns through the neutral. If they aren't equal, it shuts the circuit down in milliseconds. In a perfect world, nothing should be going through the ground. That's why you should have a GFCI, the ground probe may be working, but if it is a small voltage leak (like a cracked pump housing) the breaker won't detect it. The GFCI will.

 

[jgvergo]

There is nothing wrong with the use of portable GFCI's. In fact, I like the idea of using them for individual loads. These are fantastic when used in conjunction with grounding probes.

A grounding probe and a GFCI protect you in two completely different and independent ways. I have both. It's probably overkill, but it's better than being killed

 

[RamsReef]

I have a Reef Keeper Elite and whenever I have the USB plugged into my computer, the Reefkeeper sensors are all irratic, i.e. Salinity probe giving way off readings...as soon as I unplug the USB, everything is fine. I've heard it is because of stray voltage. Will the grounding probe help with this?!

https://www.amazon.com/gp/aw/s/ref=is_s_ss_i_0_10?k=usb+ground+loop+isolator&sprefix=usb+ground

Try one of these friend

 

[RamsReef]

A grounding probe and a GFCI protect you in two completely different and independent ways. I have both. It's probably overkill, but it's better than being killed

Not really,
Gp alone you would need a pretty solid fault in tank to load cct up to 12-13 amps to start to trip.
GFCI alone you would need to complete the alternative ground path before it would work, (probably would tingle a bit) but your fish could be frying and breaker would just laugh.

Together is where this combo really works.

 

[Brew12]

Why isn't absolutely necessary to plug the grounding probe into the GFCI?

If your house is wired correctly, all of your grounds are tied together without interruption. They then connect to a ground rod driven into the earth next to your house. From the standpoint of electricity, the grounds are effectively all the same so it doesn't matter which one you use.

A GFCI monitors what comes out of the power and what returns through the neutral. If they aren't equal, it shuts the circuit down in milliseconds. In a perfect world, nothing should be going through the ground.

This explains the rest. A GFCI doesn't monitor it's own ground. So it is a good practice, but far from necessary. I have 4 GFCI receptacles in my system, so my ground probe does not plug into them.

 

[jasonrusso]

This explains the rest. A GFCI doesn't monitor it's own ground. So it is a good practice, but far from necessary. I have 4 GFCI receptacles in my system, so my ground probe does not plug into them.

That's good if the GFCI is in series and shuts the whole circuit down. I don't wire them that way. I only want the GFCI to shut down that one outlet without disturbing the other things on the circuit. I can't have my kegerator lose power and spoil my beer.

 

[Brew12]

That's good if the GFCI is in series and shuts the whole circuit down. I don't wire them that way. I only want the GFCI to shut down that one outlet without disturbing the other things on the circuit. I can't have my kegerator lose power and spoil my beer.

I have 4 GFCI that are wired in parallel, with each controlled by it's own separate outlet from an APEX EB8. This way I can have a GFCI trip to take out 1 heater (which happened this week) but my backup heater, skimmer, and return pump all kept working normally.

There is never a reason to wire GFCI in series since a single GFCI receptacle can be wired to protect every downstream receptacle.

 

[jgvergo]

Not really,
Gp alone you would need a pretty solid fault in tank to load cct up to 12-13 amps to start to trip.
GFCI alone you would need to complete the alternative ground path before it would work, (probably would tingle a bit) but your fish could be frying and breaker would just laugh.

Together is where this combo really works.

I don't understand what you are saying. The ground probe protects you by offering a path to ground that has less resistance than a human is likely to have. The current flows through the ground probe instead of the person. It may (or may not) trip a breaker but in either case, it protects the person. A GFCI instantly breaks the circuit if a fault occurs. What is cct?

 

[Brew12]

I don't understand what you are saying. The ground probe protects you by offering a path to ground that has less resistance than a human is likely to have. The current flows through the ground probe instead of the person. It may (or may not) trip a breaker but in either case, it protects the person. A GFCI instantly breaks the circuit if a fault occurs. What is cct?

I believe he used cct as shorthand for a circuit.

A GFCI may not break the circuit if the fault occurs within the aquarium. The glass or acrylic of the aquarium acts like an insulator preventing a ground path. As soon as you stick your hand in the tank, you provide the ground path and the GFCI will trip. Salt creep can also create a nice ground path.
This is why a GFCI and ground probe make such a nice combination. Either will make the tank safe for a person. The two used together compliment each other and make each other work more effectively.

 

[RamsReef]

Yes, was on phone on plane, had limited amount of care to type out a better response. Brews got it.

 

[That Reefer Man]

So i took a multimeter (verified correct setting by testing wall outlet, got 120v), so i used it to test the water, its saying its like 50-60 volts in the water, then when i add the probe it goes up to like 90... is there a reason for this? why is my probe increasing the volts in the water? isnt it supposed to go down to 0? How would i check to make sure my outlet has ground hooked up?

thanks in advance,

 

[Brew12]

So i took a multimeter (verified correct setting by testing wall outlet, got 120v), so i used it to test the water, its saying its like 50-60 volts in the water, then when i add the probe it goes up to like 90... is there a reason for this? why is my probe increasing the volts in the water? isnt it supposed to go down to 0? How would i check to make sure my outlet has ground hooked up?

thanks in advance,

This is a potentially dangerous situation.

Check to see if your meter is auto ranging. Is it possible that it is reading 90 mV and not 90V?

To verify your ground is hooked up at the outlet, just pull the cover plate and make sure that 3 wires were run to the outlet.

 

[jasonrusso]

Do a continuity test. Put one lead in the ground socket, and one lead on the ground probe. It should be zero.

 

[jasonrusso]

Do a continuity test. Put one lead in the ground socket, and one lead on the ground probe. It should be zero.

Better yet, put it in a ground socket on another outlet. You will still get a zero resistance even if the outlet is not properly grounded if you test the same outlet.

 

[That Reefer Man]

thanks for the quick reply.. my multimeter is a "Velleman DVM890F" and i have it on the 200 V~ setting, as i mentioned im getting 120.0 or so from the wall and like 50.0 - 60.o in the tank without the probe in..

i took the cover to the outlet off, there are multiple wires going into the back and it looks to have the ground wire hooked up to the screw on the side that says GR

not really sure where to go from here....i just bought 2 ground probes new on amazon last week and now they seem to only increase the V in the tank...

thanks again,

 

[That Reefer Man]

wait, am i supposed to test the voltage in the water by placing a probe in the water and a probe in a ground in the outlet, or do i use the neutral side of the outlet?
I am now getting readings of 30 - 40 v without probe and it reads 0.0 with the probe now, but thats when testing it from a ground instead of neutral

am i supposed to leave the probe plugged in all the time even when im working on the tank?

 

[Brew12]

wait, am i supposed to test the voltage in the water by placing a probe in the water and a probe in a ground in the outlet, or do i use the neutral side of the outlet?
I am now getting readings of 30 - 40 v without probe and it reads 0.0 with the probe now, but thats when testing it from a ground instead of neutral

am i supposed to leave the probe plugged in all the time even when im working on the tank?

In reality you can test to either the neutral or the ground. They should be tied together in your electrical panel or the supply transformer and read identical. I always prefer to use the ground prong since I find it easier to get good contact with my test probe.

When you are working on your tank is the most important time to have it installed. It won't protect you if it is not in the water with you. I take mine out every few months to wipe it down but otherwise it stays in all of the time.

 

[Bebow]

Good thread! Electricity + water = danger. Over the last 6 or 7 years I've had 3 Hydor power heads leak voltage into my tank, fortunately I use the Finnex metal cased heaters which grounds the outer case directly to ground just like a ground probe. The GFCI tripped saving my but! Then it was just a matter of tracking down the bad power head.
Always, always use a GFCI! Some of mine are wired in and some are plugin. The plugin ones are so easy and add a few extra outlets.

 

[GK3]

thanks for the quick reply.. my multimeter is a "Velleman DVM890F" and i have it on the 200 V~ setting, as i mentioned im getting 120.0 or so from the wall and like 50.0 - 60.o in the tank without the probe in..

i took the cover to the outlet off, there are multiple wires going into the back and it looks to have the ground wire hooked up to the screw on the side that says GR

not really sure where to go from here....i just bought 2 ground probes new on amazon last week and now they seem to only increase the V in the tank...

thanks again,

There is no way you are getting 50-60 V in the water. If you touched the water it would shock the crap out of you. The resistance of wet human skin is approximately 1000 ohms. That means if you stuck your finger in the water and grounded yourself, you'd get hit with 50mA. Your on the edge of almost causing muscle contraction. So either you never stick your hands in your tank or something is wrong with the multimeter or the way the measurements are being interpreted.

There are 4 plugs on the bottom of your voltmeter. You have black in COM, which one is the red wire plugged into?

Also - if you aren't familiar with and used to working with electricity, I'd be careful when unscrewing and poking around behind your walls. 120VAC won't just hurt, it can kill you. Be careful.

 

[That Reefer Man]

Hello and thanks @GK3 for the response,
yes the black is in the COM one and the red is to the right of it in the V(ohm)Hz port. is that correct?

I have added grounding probe and GFCI to my tank now, getting a reading of 0.0 now

thanks again,