ECN Forum Forums General Topics of the Trade General Discussion Area ground and neutral

can someone please explain the differance between the ground and the neutral?

You might want to do a word search of the different forums here. This is a difficult question, but it has been covered before.

Good luck.

Rick Miell

The word "ground", by itself, has no meaning in a technical discussion.

Here are some valid technical terms involving the word ground, and they all have different meanings.

- grounded conductor,
- system grounding conductor,
- equipment grounding conductor,
- grounding electrode,
- grounding electrode conductor,

The neutral conductor of a system, when one exists, is the one that is intended to have a voltage such that the voltage difference between itself and each of the other conductors of the system are equal in amount, and equally displaced in phase (out of phase by the same number of degrees).

Neutral conductors only exist in polyphase (three phase) or single-phase, three-wire circuits, and are normally required to be grounded, but not all grounded conductors are "neutrals".

Ed

I'll give a simple but not quite complete answer. But since your question is pretty basic, I'll assume you're not asking for too much techeeze.

Electricity flows from the hot wire (usually black or red, although it can be lots of colors) through the lightbulb (or toaster or computer) and into the neutral wire (white or grey).

The hot and neutral wires are what are supposed to be used to carry electricy. If something goes bad, there is a ground wire to give the electricity a safe path to...ground or back to the electrical panel.

Normally, if everything's working fine. The ground wire doesn't carry any current. Ground is typically bare or green.

But the ground and neutral wires are tied together at some point back at the service entrance equipment and at the street. This keeps the neutral wire in your house and your neighbors houses at the same voltage (That is zero volts) So the neutral wire is refered to as the grounded wire but not the ground wire.

Now there are lots of times where you use two hots and no neutral (Anything that's 220Volts at home) or even three hots (but probably not in your house). And lots of other exceptions. Blah blah...don't sue me...blah blah...disclaimer...blah blah...hire an electrician...etc.

Fredster,
A Neutral, in my understanding of the term,
is a Return conductor, for an installation or a single circuit, all this means is that there is a circuit, between the incoming wire
and the voltage source.
An Earth (Ground), is used for safety purposes only, for the protection of metal bodied appliances, etc, in case a Live Wire contacts the body of the appliance, etc.
This will normally operate a fuse, to make the circuit safe.
Hope I haven't confused you.

[This message has been edited by Trumpy (edited 02-04-2003).]

Be advised that the neutral wire is not the "return" wire. While it would be simplistic to visualize current flowing in only one direction; Alternating Current changes direction 60 times a second. So in reality the neutral wire is the return wire only half of the time.

The term neutral refers to the center or (neutral) tap on the transformer. As in (Forward Neutral Reverse) on a vehicle. The transformer taps on each side of the neutral provide the two hot conductors.

The neutral is grounded at the transformer and at the service entrance in order to insure the integrety of the neutral. As some of us have found out if the neutral is compromized and there is not a back-up pathway to conduct the current that normally returns through the neutral it will return via the other hot conductor. This will result in higher voltages than normal being applied to some circuits and causing a lot of problems. By "grounding" the neutral at the transformer and at the SEP you provide an additional pathway for the current to return to the transfomer.

Grounding of appliances is a seperate topic. The grounding wire or ground inside an appliance is there to make the frame of the appliance the same (electrical potential) as the ground that one is standing on. Thus if a hot wire inside the appliance touches the frame it will short out against the frame (hopefully causing the breaker to trip) and prevent you from being an unintended pathway for the current to return to its source.

[This message has been edited by dturner (edited 02-05-2003).]

maintenanceguy:


It is my understanding that the 2002 NEC requires appliances to be grounded when connected by cord and plug?

Creighton Schwan wrote an article (Nov., 1999 Electrical Contractor Magazine)describing the differences between the grounded, grounding, and bonding conductors. He explains their uses and goes through a sizing scenario for each of these conductors. Good article. I have it copied in MS Word format if someone is interested in reading it. (dnewton@guidant.com)