🚀 go-pugleaf

>Ground and neutral are exactly the same thing.  If you were to trace the
>wires back to your breaker box, you would find bare wires (ground) and white
>wires (neutral) both connected to a grounding strip.  The hot wire's potential
>varies from ~170V above ground to ~170V below ground.  The two wires that come
>from the pole are both hot, BUT, the sine waves are 180 degrees out of phase
>with one another, so when one is at +170, the other is at -170, and if you
>connect something to those two, you will have a 340V sine wave.  (values are
>peak, not RMS...RMS would be about 120 and 240).

Well, they're the "same thing" before you have any current, but they're
definitely NOT the same thing from that point on.

The difference is that the "white wire" neutral is the *intended* return
path for current on the circuit; as such, it is always, at any outlet on
the branch, at some potential above ground due to the effect of such
current and the resistance of the neutral wire (E=IR, right?).  It is
NOT "guaranteed" to be at zero volts.  The "green wire" ground, though,
normally carries no return current, and so is always at a lower potential -
zero, unless some current is flowing in the ground wire due to a fault
condition.  The idea to to give the lowest possible potential on the
"ground" wire in the event that a fault does occur, and so requires this
wire to carry return current.

>MY QUESTION is, if you don't have 3-wire connections in your house, why
>can't you connect the white wire to the ground lug and conuit/boxes, etc???

See why now?  You DON'T want the ground wire to normally be carrying return
current, or else it would be at some potential above "ground "at the outlet.


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
myers@fc.hp.com                          |  sentient life-form on this planet.