> But as a physics teacher he probably has heard about galvanization, oxidation and similar chemical things.. I hope. As the post says > I learned two things

> But as a physics teacher he probably has heard about galvanization, oxidation and similar chemical things.. I hope. As the post says > I learned two things [...] (2) GFIs only trip off when in bodies of water that are grounded. They won’t work in an aquarium sitting on a lab table, or in a plastic laundry sink with plastic drainpipes, or in a plastic shower with plastic drainpipes. I'm neither an electrician nor a physics teacher but I knew that these devices looking for ground leakage work only when the electricity leaks to ground (I guess that's what GFI refers to; I know them as aardlekschakelaar, literally: earth leak switch). That's also why I find it so weird that this teacher describes the functioning as "detects that current is leaking out some other route than expected": it's not like electrons have routing labels you can match against an itinerary. It can very well flow through your body before returning via the normal return wire. Rather, the device detects electricity coming through the ground wire, and so it stands to reason that you need to close the circuit into that ground for it to observe the fault... Why else do all electrical devices with a metal case or a metal structure have these metal bits connected to ground, if not so that most shorts will lead to the circuit being closed towards ground? Anyone who ever took anything electrical apart has seen these extra cables -- I did last week while cleaning the dehumidifier for example. I applaud careful experimentation as they did with the hairdryer and, presumably, the toaster (using it on a protected circuit, observing if it works correctly, etc.). But there are also quite a few sentences in this post where my eyebrows moved