Re: AC socket/wiring questions

firebird wrote:

My answers refer to common residential practice in the US.

1. Is the Hot wire more insulated than the neutral?

No. They have the same kind of insulation. Hot is normally black (may be red if second hot is used), neutral normally white. The safety ground wire is either uninsulated or insulated with green or green with yellow stripe.

If so, why? If the current is the same at all points in a
> circuit, the neutral wire will carry all the current coming
> in from the hot wire back to ground...
> so why have less insulation for the neutral wire?

Where have you seen less insulation on a neutral?

2. Also, why do we need a third prong when the neutral is already
connected to ground? Is the third prong only there to overcome the
hazards of faulty wiring (hot to neutral socket and neutral to hot
socket)? If so, can't the third prong be wired incorrectly as well
(albeit very rarely)?

The safety ground conductor is there to keep conductive parts of appliances at a safe potential (with respect to the Earth) in the event of leakage between the hot wire and those parts, or to blow the fuse or circuit breaker on the hot wire, in the event that the hot wire comes into contact with the exposed conductive parts of an appliance.

3. Is it true that the third prong is grounded close to the building
and the neutral is grounded far away at the power station itself? If
so, why?

No. Both are grounded at the power panel. This provides a low resistance path back to the fuse or circuit breaker in the hot to case short situation.

The neutral is also grounded outside at the distribution transformer that performs the last voltage step down to the residential voltage of 240, center tapped. The center tap is what is grounded.
.

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