Electrical question

[Delphinus]

One of my skimmer pumps is leaking voltage..

Is there anything to look for in terms of seeing if the pump can be salvaged?

I'm sort of suspecting "no" but I thought I'd give the pump a once-over tomorrow nonetheless. Likely though I'm buying a replacement ...

Question #2 ... why wouldn't it have tripped the GFCI if I have a grounding probe? Is there a minimum threshold for creating a ground fault?

I realize that the skimmer being in the sump that the ground probe should also have been in the sump, but I could feel the trickle of electricity in the display so I thought it would have gone to ground and thus tripped the GFCI? The GFCI trips pretty easily in other circumstances.

Just wonderin' .. thanks

[midgetwaiter]

If you can feel it there's enough current to trip the GFCI, UL mandates a 6mA threshold. Does it trip if you put the probe in the sump? If not I'd test and replace that GFCI.

For the pump you could maybe pull the plastic off and slop some epoxy around where the cord terminates but I'd never trust it.

[sphelps]

Different GFIs have different ratings. You shouldn't be able to feel the voltage if using a ground probe, if you can feel it the probe isn't working.

It should be noted almost all submerged pumps will put some voltage in the water, but it should be very little. The problem comes from placing an electric motor in a highly conductive salt bath which can result in electromagnetic induction, which will produce a voltage source. This is different from so called "stray voltage" as it is not power leaking from the supply but rather power generated from the magnetic field within the pump.

Also measuring the voltage within the water actually tells you very little about this kind of situation, you really need to measure the current.

[Delphinus]

I seem to have misplaced my multimeter so I'm unable to measure current. Might have to just pick up a new one, I've lost it pretty good, I don't think I've used it since before I moved .... four years ago.

Anyhow it was sort of through a serendipitous sequence of events that I found it. Indeed with the grounding probe in, I can't feel the tingling in the main tank. I was just moving some things around and had the probe unplugged and noticed it. Then while trying to find it, I brushed my hand against the air intake tube of the skimmer (it's covered in salt spray) and that's when I really felt the zap-zap-zap-zap (didn't feel like a full 110 though ). I just thought it was odd that if I say, spill water on the floor and the puddle touches the return pump, the GFCI kicks off no problem. I've also managed to kick the GFCI off by strategically () spilling water during water changes (hey, I'm a klutz, what can I say. ) ... So I know the GFCI trips in other circumstances, just thought it was odd it did not in this one.

But I bet it will trip if I move the GFCI to the sump. Will try that tonight and see what comes of it. Guess it goes to show you really need ground probes in both the main tank AND the sump, if indeed it trips fine then.

[Black Phantom]

I currently run GFCI's with all my aquarium equipment but am a bit confused.
Do I need to run a ground probe in the tanks for the GFCI to do it's thing. Better yet, have I been reaching into the tank all these years thinking I'm safe when I really haven't been?

[Delphinus]

Yes, it would be better to run a grounding probe. The GFCI will trip on a ground fault which in the absence of a grounding probe in the tank means it pretty much means it can only shut off if water gets onto a plug (ie., thus connecting one of the hot or neutral wires to ground -> thus "ground fault" -> thus tripping GFCI).

Without a ground probe in the tank, a submerged electrical device may have a leakage but without a path to ground the electric potential has nowhere to go. Thus if you stick your hand in the tank and say, your foot or something connects to ground (not the "ground" as in "floor" but I mean "ground" as in "somewhere for the current to go to") then you become the ground, thus getting zapped and bypassing the GFCI. Whereas a ground probe would be a better ground than you, and thus the electrical current would go there instead.

At least that's how I understand it.

[sphelps]

I really don't like to get into this kind of discussion as everyone always seems to have various opinions and comments and no conclusion in ever resolved.

However to contradict myself I would first off never use a ground probe. Ground probes create current from stray voltage, once you have current you have danger. Saying that you're safe because the ground probe is always a better ground than yourself is false, if you come between the voltage source and ground probe you could be in a lot of trouble, much more than if the ground probe wasn't there. Secondly almost all electrical components are going to create a small amount of stray voltage, however this is harmless and will not trigger a GFI. Add a ground probe and now you've given all those components potential, meaning they have somewhere to send that voltage and sometimes will send more because of it. This results in a loss of current which can trigger a GFI. Some say great, then I'll know when something is wrong. But what happens when it triggers on that long weekend when you're out of town??

Basically argue all you want but you really shouldn't use both a grounding probe and a GFCI together. It's unnecessary and they can interfere with each other. GFCIs are designed to trigger the second current is lost, it will trigger before you're zapped, you do not need a ground probe.

[Delphinus]

I didn't think I was arguing. Not sure where you think I was, not my intent at all.

If it's better to run without probes then so be it. I gave my reasoning and the disclaimer that this was how I understood it - if the reasoning is faulty then I appreciate the gesture of being corrected. So what you're saying is a "ground fault" is an unbalance of hot and neutral? Ie., it doesn't mean there's current on the ground wire?

One point though, I would rather lose a tank on a long weekend than my life. **If** it really came down to that. But it's comforting to note that the absence of a ground probe doesn't mean you're at risk.

I just don't like being electrocuted is all.

Peace?

[Monti-Man]

I am an electrical engineer and I will tell you that a ground probe is neccessary, that is why it is built in to everything from house to idustrial sites as syncrude.
You are always better having one

[sphelps]

Originally Posted by Delphinus

I didn't think I was arguing. Not sure where you think I was, not my intent at all.
Peace?

I wasn't referring to you arguing, just that this topic always starts these kinds of arguments, so I was referring to future arguments not past ones.