[time-nuts] AC Connector On HP 5061B

Chuck Harris cfharris at erols.com
Thu Oct 2 17:18:24 EDT 2008

Lux, James P wrote:

> In the U.S., depending on where the installation is (residential vs industrial), the neutral ("groundED conductor")
> is bonded (code-speak for permanently connected) to the earth ground at the service entrance panel. The safety ground
> ("groundING conductor" aka green-wire ground) runs separately from that point.

That is true on 120V 15 or 20A circuits, whether you are industrial,
or residential.

> If you have a 15A receptacle (NEMA 5-15R, for instance), there is a rule about which slot connects to neutral and
> which to line (wider is closer to earth ground, e.g. neutral).  And, on screw in light fixtures, the neutral must be
> connected to the shell (so that if some of the male thread is exposed, it's at lower voltage relative to the grounded
> fixture.
> There are lots of configurations possible (including, for instance, balanced 120V, where each side is 60V relative to
> earth ground) still using the NEMA 5-15R configuration.

To the best of my knowledge, that configuration is only found in marine applications.
NEC doesn't allow it on shore.

> And, there's a lot of stuff when you're running off an isolated power source (e.g. a generator or UPS).
> And, if you're in an industrial or office environment, fed with 3 phase power, there's all kinds of strange
> configurations possible (e.g. delta, with the midpoint of one phase winding grounded, or Wye/Star with the neutral
> bonded through a high impedance to ground).

True, but they all end up the same as the residential 120V circuit, with the
black wire hot, and the white (or grey) neutral bonded to the service panel.

-Chuck Harris

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