Grounding Probes Worth It?

saltyfilmfolks · Dec 4, 2017

ontop27 said:
Wouldnt it travel the path of least resistance?

Brew and I are friends and both work with Electricity.

Yes it would. But if there is no path where would it go? It doesn't. So the probe provides that path.

ksed · Dec 4, 2017

@Brew12 @revhtree I think GFI and grounding probes should have their own sticky thread. This way many can refer back to the thread and also possibly a life saving thread. Just a suggestion.

DSC reef · Dec 4, 2017

I believe there's a sticky under general reef discussion

Daltrey · Dec 4, 2017

I use that same one and also two gfci outlets on two separate 20 amp breakers that I installed myself and then checked for proper ground.

Also I'm no electrician but my dad is and I learned from him.

rkpetersen · Dec 4, 2017

I'm using a high resistance grounding probe. I wanted to protect myself from possible electrocution, but I also did not want my GFCI opening unexpectedly, particularly if I'm away from home, when there's no immediate danger to the aquarium or the house. My system is highly automated but aA 1 watt or larger 1000 ohm resistor placed in the cord of the grounding probe can help keep minor failures and induction from tripping the GFCI, while allowing the probe to continue to provide protection against dangerous current as it remains the path of least resistance. It also reduces any voltage gradient effecting the tank as the voltage drop now occurs in the resistor.

Brew12 · Dec 4, 2017

ksed said:
@Brew12 @revhtree I think GFI and grounding probes should have their own sticky thread. This way many can refer back to the thread and also possibly a life saving thread. Just a suggestion.

Glad you found it useful

DSC reef said:
I believe there's a sticky under general reef discussion

There is. You can find it here.
https://www.reef2reef.com/threads/using-ground-probes-in-aquariums.270479/

Brew12 · Dec 4, 2017

rkpetersen said:
I'm using a high resistance grounding probe. I wanted to protect myself from possible electrocution, but I also did not want my GFCI opening unexpectedly, particularly if I'm away from home, when there's no immediate danger to the aquarium or the house. My system is highly automated but aA 1 watt or larger 1000 ohm resistor placed in the cord of the grounding probe can help keep minor failures and induction from tripping the GFCI, while allowing the probe to continue to provide protection against dangerous current as it remains the path of least resistance. It also reduces any voltage gradient effecting the tank as the voltage drop now occurs in the resistor.

That is an interesting concept but I wonder how much value it has. Induced voltages won't trip a properly functioning GFCI. Inductive kick from ballasts can, but the ground probe isn't involved with that.

Since a GFCI trips at 5mA it will only prevent a GFCI from tripping if the fault location drops less than 5 volts. So nothing wrong with doing it, but I wouldn't recommend anyone not comfortable doing wiring work from trying it.

rkpetersen · Dec 4, 2017

Brew12 said:
Since a GFCI trips at 5mA it will only prevent a GFCI from tripping if the fault location drops less than 5 volts.

Exactly. One could definitely adjust the size of the resistor for different voltage cutoffs. But I'm fine with 5 volts. It's just a safeguard against possible small random events. Any larger electrical issues, I want to identify and fix.

Your idea of having multiple separate GFCIs is a good one, but difficult to achieve if you also want to have your system on a UPS.

Brew12 · Dec 4, 2017

rkpetersen said:
One could definitely adjust the size of the resistor down to, say, 500 ohms for 10 volt cutoff, 250 ohms for 20 volt cutoff, etc. But I'm fine with 5 volts.

Other direction... more resistance for higher voltages. But your point stands, it is very adjustable with easy math.

rkpetersen said:
our idea of having multiple separate GFCIs is a good one, but difficult to achieve if you also want to have your system on a UPS.

It isn't even going to be practical with my new tank. Since I used MP40's as my primary flow I didn't have them on a GFCI. I'm going to be using gyres and installing 6 gfci's isn't going to happen. Instead, I'll use 2 GFCI's and try to split my loads between them. I'll put one light fixture on each so I know one has tripped by the fact a light is off. A UPS makes it even more challenging.

rkpetersen · Dec 4, 2017

Brew12 said:
Other direction... more resistance for higher voltages. But your point stands, it is very adjustable with easy math.

You're too fast! I noticed shortly after posting.

Biglurr54 · Dec 4, 2017

Interesting. I'm planning a large tank install and was going to do 2 20a gfci circuits. I understand how the ground probe would cause one gfci to trip but would the grounding probe be as effective on the circuit that it is not plugged into? I need to add a grounding probe for my tank after reading this. I think back to all the years of no gfci and no grounding probe. Just Russian roulette because of tight budgets.

skiergd011013 · Dec 4, 2017

I have this exact same one. That, and everything plugged into gfci. I also always look and make sure fish are swimming before i put my hand in a fish tank. Im paranoid about electricity.

Brew12 · Dec 5, 2017

Biglurr54 said:
Interesting. I'm planning a large tank install and was going to do 2 20a gfci circuits. I understand how the ground probe would cause one gfci to trip but would the grounding probe be as effective on the circuit that it is not plugged into? I need to add a grounding probe for my tank after reading this. I think back to all the years of no gfci and no grounding probe. Just Russian roulette because of tight budgets.

It doesn't matter where the ground probe plugs in. All of your house grounds should be tied together. A GFCI does not look at ground current, it only compares the hot to the neutral. As long as some current from the GFCI goes to any ground it should trip.

skiergd011013 said:
I have this exact same one. That, and everything plugged into gfci. I also always look and make sure fish are swimming before i put my hand in a fish tank. Im paranoid about electricity.

You can stop looking at your fish

Unless your tank gets so hot that they start cooking or the failed equipment leaches a lot of toxins the fish won't show more than irritation.

Biglurr54 · Dec 5, 2017

Thank you for the explanation. That makes sense. How are gfci and probes playing with apex? Have there been any issues.

Daltrey · Dec 5, 2017

Brew12 said:
Other direction... more resistance for higher voltages. But your point stands, it is very adjustable with easy math.

It isn't even going to be practical with my new tank. Since I used MP40's as my primary flow I didn't have them on a GFCI. I'm going to be using gyres and installing 6 gfci's isn't going to happen. Instead, I'll use 2 GFCI's and try to split my loads between them. I'll put one light fixture on each so I know one has tripped by the fact a light is off. A UPS makes it even more challenging.

I bought my gfci’s at lowes and they have a siren built in. It is loud like a smoke alarm and I can hear it across the house. My powerheads I have hooked up to a deep cycle marine battery as backup that would last at least a week. I have two seperate gfci each on their own 20 amp circuit. Each have a seperate heater and powerhead.

Brew12 · Dec 5, 2017

Biglurr54 said:
Thank you for the explanation. That makes sense. How are gfci and probes playing with apex? Have there been any issues.

Some people have seen improvement on the conductivity and ORP probes but I haven't heard of anything negative. I use them with my Apex.

Brew12 · Dec 5, 2017

Daltrey said:
I bought my gfci’s at lowes and they have a siren built in. It is loud like a smoke alarm and I can hear it across the house. My powerheads I have hooked up to a deep cycle marine battery as backup that would last at least a week. I have two seperate gfci each on their own 20 amp circuit. Each have a seperate heater and powerhead.

I need to look into that for the new system I'm building! Haven't seen those yet!

Daltrey · Dec 5, 2017

Brew12 said:
I need to look into that for the new system I'm building! Haven't seen those yet!

These are the ones I use

https://www.homedepot.com/p/Leviton...-Audible-Trip-Alert-White-GFTA1-0KW/206280966

Don Lidtke · Dec 5, 2017

I use them plugged into a GFCI. I would rather pop a breaker than shock myself. I am not a fan of 110 VAC biting me!

RamsReef · Dec 5, 2017

Brew12 said:
That is an interesting concept but I wonder how much value it has. Induced voltages won't trip a properly functioning GFCI. Inductive kick from ballasts can, but the ground probe isn't involved with that.

Since a GFCI trips at 5mA it will only prevent a GFCI from tripping if the fault location drops less than 5 volts. So nothing wrong with doing it, but I wouldn't recommend anyone not comfortable doing wiring work from trying it.

You put a 5ver on? I thought you would have lived life and grabbed some of those 30mA equipment ones *wink*