Neutral vs. Ground

[Rico]

What is really the difference between neutral and ground.
I have noticed that the neutral wire that comes in from the utility pole is connected to the neutral tie in the main breaker panel. The Neutral Tie is however insulated from the metal panel box itself. The ground wires all connect to a metal screw that is screwed into the panel box and is uninsulated.

Now the 6 ft copper ground rod that is beneath the meter box on the outside of my house, does not seem to be connected to anything other than the glavanized Meter Box and the glavanized Main Power Switch Box for the house, which is next to the Meter Box.

Since the Neutral Line supplying the house comes from a utitlity pole where it is connected to a large ground wire that is buried in the ground next to the pole, what is the point of having in effect...two ground circuits?

Can any of the Theory Specialists shed any light on the reasoning behind having Ground and Neutral, when Neutral is grounded?

[kactuskid]

Here's a link that should give you the details:

http://experts.about.com/q/1734/3561110.htm

[Rico]

Excellent link. Thanks Kactuskid.

What I've gathered from the material is that Ground supplies a second route to ground should an appliance have an internal short that would electrify any metal housings.

Neutral does not do this as it is insulated from the appliance's (or panel's) metal housing.

Essentially, a ground wire is a second route to ground should something go wrong with external metal parts.

[kactuskid]

Your neutral and ground will be bonded together in your main panel, but they will be separate in your sub panel. Here's a few more links that fill in with more info:

http://www.faqs.org/faqs/electrical-wiring/part1/section-15.html

http://www.epanorama.net/documents/groundloop/neutral_ground_separate.html

http://members.tripod.com/~masterslic/FAQ-2/18.html

[HayZee518]

The new code coming out in 2005 (NEC 2005) talks about changing nomenclature. Grounding from 2005 out is now going to be bonded, bonding conductor. In your panel you have a lead going to a water pipe ground. This is your primary grounding path. A secondary grounding path is provided by a driven ground rod. Essentially all water piping and possibly gas piping is all bonded together forming a grounded loop. IF the ground at the transformer or crib line is broken or sheared off there IS a possibility that 220 would flow into one line creating a hazard. Your ground at the panel, water pipe and driven ground eliminate this problem and causes the primary fuse to blow. The transformer connections are X1, X0 and X3. X1 & X3 form the two 120 volt leads, the X0 is the center tap which is normally grounded. The primary is H1 and H2. H2 goes to a ground and H1 connects to the high side of the 4160 line that runs atop the pole through a primary fuse cut-out.