DIYbanter - View Single Post - Grounding--ground wire

Joseph Meehan

wrote:
On Feb 20, 9:42 am, "Pop`" wrote:
Joseph Meehan wrote:
Herb and Eneva wrote:
Will someone please explain the difference between the grounding
wire---white, and the grounded wire---green, in a circut? They both
go to the same busbar.

When everything is working as intended, the white wire carries
current and the green-cooper does not.

Correct

The only time the white is

not carrying current is when nothing on the pair of circuits is on
or when there is identical load on both legs of the circuit.

Wrong. When all is off, the white wire sits at ground potential.
When all is on, it still sits at ground potential + any tiny
voltages created by the resistance of the wire and depending on the
length of the wire.

In short the without a fault the white can kill you the green
can't.

Wrong. When all is OK, the white wire has zero or very nearly zero
volts potential.

If the green fails it can damage equipment on that circuit as it
may suddenly get 240V rather than the expected 120V.

Only if it were damaged at or outside the main panel.

You can't safely eliminate either one as they both perform
critical duties and can not be shared legally or safely.

True, but your reasoning is all Phhhttt! Please return to studying.

Pop`

Are you saying that if I grab a white wire in a household circuit and
stick my feet in a bathtub of water , that I will be perfectly fine
because both the wire and my feet are at the same potential ???

Maybe I misunderstood you ?

No, in an ideal world that would be true, the problem is we don't live
in an ideal world. The difference would be that if you cut the white wires
and held one in each hand in an unbalanced load situation you would have
current flowing thought you. If you held the the end connected to the load
and stuck your feet in the tube you could be in trouble. Doing the same
with a properly connected copper ground wires would be safe.

All the above assumes everything is working as it should and Murphy is
not applying his law to you at that time.

--
Joseph Meehan

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