7 Sep
2014
7 Sep
'14
9:05 a.m.
Tony,
On Sat, Sep 6, 2014 at 2:51 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
YEs, that is exactly what they do. If you think about it, it's tbe most
sensible thing to do.
Not to put too fine a point on it, but I +did think+ about it - and as
such, arrived at the correct functional model as outlined above.. ;-)
Honestly, I'd never really given much thought to the behavior of GFCIs.. my
vague mental model was more-or-less based on detection of anomalous
currents flowing in the ground circuit. But of course, if you think about
it (...) that would only protect against one category of fault. Once Eric
stated that GFCIs can function on two-wire circuits, it was immediately
clear that my model needed to be discarded, which forced me to re-think
matters for a moment.
So yes, detecting current differentials wrt hot & neutral is really the
best (if not the only) method to achieve the desired aims.