>
> So I was chatting with the sparkie, as you do, and asked him why
> the damage was closer to the Active/Live connection. (you can see
> in the first picture that the damage pretty much stops where the
> element turns around, ie halfway between A and N). He couldn't
> say. He said that he asked once at college why, if the current is
> AC, that Active and Neutral aren't regarded as interchangeable.
> But the answer he got was "they just aren't"

Would it be similar to why telegraph signals (or was it something
else?) use 0V and -48V, rather than 48V and 0V - that is, because
"everything else" (air etc.) are at "true ground" = 0V? So in this
case, all the water would be more or less at ground potential
(basically neutral) while all the corrosion happens where there is a
potential difference, e.g. the "hot" side.
Though that doesn't explain why this happens at AC... you'd think any
corrosive effects in one half-period would undo themselves in the
other half-period, the way that battery terminals do...

Ah well, just a shot in the dark.
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