Ground Probe

[Sherri]

So I bought a ground probe a while ago but have never put it in. I thought it was supposed to go into a GFCI outlet but it is designed to go into a regular outlet. It has a loop on the end that you put under the center screw in a regular outlet. What should I do? There is no screw in a GFCI and I assume you are supposed to plug it into the GFCI ... suggestions?

 

[cujo6984]

just pull the wall plate off and put it on the screw under there

 

[RayD]

I bought one a long time ago and never hooked it up. Is it really necessary?
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[Sherri]

You will find as many people who will say it is necessary as not. I have had it for a long time too and finally decided to do it. The basement has concrete floors which can be dangerous. The argument against has to do with the fact that what you are doing is making it worse by completing the circuit with the ground probe. That is why I guess you want it to go through the GFCI....

 

[cujo6984]

im not 100% positive on this but if you do complete the circuit. with the ground not through the GFCI as long as the source is running through the GFCI it should trip

 

[Sherri]

The only thing that does not go through the GFCI is the lights. I am also not sure if one will do it for the whole system? Or does there need to be something in both DT's and tanks in the basement? I mean my whole system has 6 tanks -- 2 display tanks and then four in the basement. If I am going to do this I should do it the right way. With the external pumps one is the CL and just goes up to the display and the other, the return pump pumps up -- so a ground probe downstairs will not do much for the DTs.

Also, if I am simply putting it in the screw in the middle, does that just ground it on the same ground as the rest of the wires? Sorry -- not an electrician.

 

[cujo6984]

i think you will only need one probe because if you think about it everything is connected by water even if they are in separate tanks

 

[Sherri]

That is what I thought but then I read somewhere where someone was putting in multiples. I only bought one which is all that I thought I would need. But here's a thought. IF some stray voltage is coming from one of the big external pumps, and the water flow has it going through the DT before it gets to the tank with the ground probe in it -- wouldn't the current then follow the flow of the water? So while I might not have stray voltage, what I do have is a current that flows through the DTs? Or does it go the shortest distance even if it is against the flow of the water?

 

[cujo6984]

i dont think flow really makes a difference

 

[Sherri]

I finally got a chance to ask hubbie -- said you are right -- flow is irrelevant -- goes the shortest distance -- so one is enough.

 

[Dragon2115]

Distance and flow have nothing to do with it. Electricity will follow the path of least resistance. That's what the grounding probe does, create a path that has less resistance than you do.

A GFI measures the amount of current that goes into a load (pump, light, etc) and compares it to how much comes back out. If the difference is too great it means that there is a leakage path and the GFI trips. It is quite possible to charge the water in the tank to a substancial voltage and if there is nowhere for it to go it won't trip the GFI. If you happen to be grounded (standing barefoot on concrete for example) then you can still get quite a jolt before the GFI has a chance to trip. The plus is that it'll be quick and you won't stay connected to the mains for long. However if you have a ground probe installed, and it's a good idea to have one near any submerged piece of equipment so that if there is a malfunction and something couples to the water the path to ground doesn't go through the entire tank, as soon as there is leakage current the GFI will trip. By using both GFI and ground probes faults are detected right away.

 

[emabie]

That is what I thought but then I read somewhere where someone was putting in multiples. I only bought one which is all that I thought I would need. But here's a thought. IF some stray voltage is coming from one of the big external pumps, and the water flow has it going through the DT before it gets to the tank with the ground probe in it -- wouldn't the current then follow the flow of the water? So while I might not have stray voltage, what I do have is a current that flows through the DTs? Or does it go the shortest distance even if it is against the flow of the water?

You are correct about the electricity taking the shortest route. However, I think you still need one in each display and in the sumps. When everything is turned on and running the one probe could cover the whole set up.

When you turn off a return pump you break the circuit from the sump to the display by stopping the flow of water.. It's during tank maintenance that you typically turn off your return pump and put your hands into the water. So this could potentially cause a shock with just one ground probe. Specifically if you put your hand in the tank that has the voltage leak and the ground probe is in the other tank that no longer has flow connecting it to the one with your hand and the leaky current.