Rodney Kelp wrote:
Ok, For those who worry, I am NOT wiring a house like this. This is only
theoretical.
So from what you say I see that the short jumper,
There is (should be) no such jumper. Case closed.
If you see such a jumper, get your wiring reviewed by a competent
electrician before somebody gets electrocuted.
on a 3 wire outlet,
from the green case ground post to the silver white neutral post has the
same potential as the bare copper safety wire has from the green case ground
post to the neutral binding posts in the breaker box panel.. Barring all
possible disasters Is there any electrical difference that the outlet sees
where you plug things in?
If the outlet is drawing 20 amps then isn't it felt at the breaker box paned
neutral connection where the equipment ground is connected?
As a matter of fact isn't the bare copper safety wire seeing the entire
house current at that neurtal connection in the breaker box panel at the
outlet's safety ground?
I suppose that depends on what you mean by "seeing," but as you say,
it's just a theoretical question.
"w_tom" wrote in message
...
Appreciate that wire is not electrically same at both
ends. Wire is not a perfect conductor. Wire is treated as if
it was another electronic component. How much difference
exists between two ends of a wire is determined by
characteristics of the current in that wire - ie. amperes,
open circuit driving voltage, frequency, harmonics, etc. Most
of this will be well beyond the scope of this discussion.
But human safety demands that any electrical appliance be
connected as best as possible to the safety ground inside
breaker box panel (point where safety ground wires, white
neutral wire, utility neutral wire, and earth ground wire all
meet). The only wire that can make such a connection is one
that is not carrying any current - the bare ground wire. Even
though the white neutral wire also meets at that point, the
white wire has significant differences at both ends - because
white wire is carrying up to 20 amps current.
Others have provided examples of why the white wire and bare
safety ground wire are completely different wires at the wall
receptacle. Bottom line - the white wire and bare safety
ground wire are only same where both meet at the breaker box
safety ground.
You may even be able to see this difference with a digital
volt meter. When AC outlet powers a significant load (ie
toaster or steam iron), then a voltage difference should exist
between white neutral wire and bare copper safety ground wire
at that wall receptacle.
Are white neutral and bare copper safety wires properly
isolated? Breaker box GFCIs tend to trip (cut off power) when
bare copper white is shorted (connected) to white neutral wire
anywhere but inside the breaker box. Just another in a long
list of examples that demonstrate why white neutral and bare
copper safety ground wire are electrically different. Why one
wire cannot perform both functions.
Rodney Kelp wrote:
If you have a 2 wire house electrical system what's the difference
between a 3 wire system and installing a 3wire plug and jumping the
ground pin to the white return line. I see no electrical difference
between that and running a green wire all the way to the box and
connecting it to the same place as the return line ground. If you
know what I mean.
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