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  • Neutral

    Can someone smart explain exactlly how voltage you can get voltage on the neaural side. I know for circuit boards it's very bad. Other than a short, it's possible to be screwed up at the street level right?

    Another question. Since the neutral and ground are tied together inside a breaker panel, do you have to run a line AND neutral to a sub panel....say garage. I think IL code says you can't run the ground back to the main panel (you need a ground rod) so why can't you do the same with the neutral.

    If you have voltage in, it has to come out, and it wants to get to ground. So it would seem a neutral is sort-of a hard wired ground.

    Eh, my brain is aching now, any help would help.

  • #2
    Re: Neutral

    Remember, all voltages are measured with reference to ground (Otherwise known as common) If there is a difference of potential (with reference to ground) then there will be a difference. So if you are reading a voltage on the neutral. Then that means there is a potential difference with the ground as a reference.

    Now for the subpanel, the ground and neutral HAVE to be run separately for the feedres, and the branch curcuit conductors from the sub panel have to remain separate as well. Mean the neutral and grounding busbarrs/ termanal bars have to be sparated in the sub.

    Also, voltage can be induced the electromagnetic field generated from the "hot' conductor, to the neutral. A principal non-contact voltage detectors operate on.


    • #3
      Re: Neutral

      The neutral conductor carries the unbalance current. Using the main service panel for an example, you read 20 amps and leg (A) and you read 15 amps on leg (B). This will indicate that the neutral conductor is carrying 5 amps of current.
      At the devices (receptacles) the neutral will carry the same amount of current as the hot conductor, provided it is connected to something and there is sufficient load to get a measurement.

      When running a feeder for any sub panel (attached structure or unattached structure) a ground conductor (wire) is required. In some instances the conduit can be used for the grounding conductor (EGC). In an attached structure a ground rod is not required, in an unattached structure at least one ground rod is required. In most jurisdictions 2 rods are required for all services and feeders.
      All feeders after the implementation of the 2008 NEC, must consist of 4 wires H-H-N-G.

      The neutral is not the ground. It is the grounded conductor. The ground is present to carry fault current, such as when you short out a circuit.
      The neutral carries current all the time when the electrical system is energized, and there is a load present.

      Current is not looking for a low path (low impedance) to ground as many people believe. It is always looking to return from where it has come. This is usually the transformer supplying the dwelling or structure.
      Licensed Electrician