Quote:
Originally Posted by midgetwaiter
This is technically incorrect. What A GFCI does is detect that there is current leaving on the hot wire that is not being returned on the neutral. ie it is going to ground through you, this is when it trips. In Steve's situation the current didn't have a path to ground, the GFCI may not have stopped anything
A ground probe could also save you in the "knock the lights in" situation. If there is a device leaking current into the water the ground probe gives it a path to ground. The "save you" function of a ground probe is pretty simple, that current wants to go to ground and hopefully the probe provides a better way to do that than you do.
Talking about a ground probe "removing" stray voltage is also flawed. The assumption is that having this stray current in the tank is bad for the inhabitants but there isn't a lot of proof for it. A leaky device is giving you potential current but it's not until you get a path to ground, ie your probe, that you have current flowing through the water. Think about a bird on a power line. Touching one line, no problem but touch another line or the ground at the same time and you have a big problem. Is potential current or a completed circuit worse for fish and inverts? I don't think there is a definitive answer.
The thing that could have saved Steve's critters is both a GFCI and a ground probe. When the heater broke the current would have gone to ground rather than returning on the neutral and it should trip. This probably would have worked but I think you'd have to look far and wide to find many people that use both these devices.
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Yes, to be specific I would have prefered to say that the GFCI trips when an appliance uses electricity in a way not normally anticipated (my bad). I was being somewhat general on the point as I was trying to illustrate the difference between a surge protector and a GFCI. Some people assume a surge protector on a powerbar will protect them which, of course, is false. I also made note that I didn't know if it would have helped in that situation. My main intention was to help others protect themselves while working near saltwater.
It's interesting that this type of discussion doesn't come up more considering the amount of electrical appliances used in close proximity to an excellent conductor like saltwater. Like plumbing a tank I always try to plan for the worse case scenario.
I'm a little worried about your contention that a grounding probe is as protective as a GFCI though. If you want to bet your life using a grounding probe that might
outground you vs a GFCI that
will save you go ahead - but please put me in your will first
In the first paragraph you say a grounding probe removes stray voltage and then you say it's flawed. Do you mean that it will remove the voltage but the need for doing so is not definate? I don't know about the fish and corals but I just recently worked on a tank that was constantly giving me low voltage shocks. The reason was a non submersable heater be used as a submersable. I sure would have appreciated that probe. I don't really have an opinion on the effect on fish and corals though - don't know.
And lastly, I have both - I'm such a scaredy pants
