10 | SAMLEX AMERICA INC.
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cAUtion!
PleASe note tHAt tHe Ac oUtPUt connectionS AnD tHe Dc inPUt connectionS
on tHeSe inVeRteRS ARe not connecteD (BonDeD) to tHe MetAl cHASSiS oF
tHe inVeRteR. BotH tHe inPUt AnD oUtPUt connectionS ARe iSolAteD FRoM
tHe MetAl cHASSiS AnD FRoM eAcH otHeR. SYSteM GRoUnDinG, AS ReQUiReD BY
nAtionAl / locAl electRicAl coDeS / StAnDARDS, iS tHe ReSPonSiBilitY oF tHe
USeR / SYSteM inStAlleR.
conDUctoRS FoR electRicAl PoWeR DiStRiBUtion
for single phase transmission of Ac power or dc power, two conductors are required
that will be carrying the current. These are called the “current-carrying” conductors.
A third conductor is used for grounding to prevent the build up of voltages that may
result in undue hazards to the connected equipment or persons. This is called the “non
current-carrying” conductor (will carry current only under ground fault conditions).
GRoUnDinG teRMinoloGY
the term “grounded” – indicates that one or more parts of the electrical system are con-
nected to earth, which is considered to have zero voltage or potential. In some areas,
the term “earthing” is used instead of grounding.
A “grounded conductor” – is a “current-carrying” conductor that normally carries cur-
rent and is also connected to earth. Examples are the “neutral” conductor in Ac wiring
and the negative conductor in many dc systems. A “grounded system” is a system in
which one of the current-carrying conductors is grounded.
An “equipment grounding conductor” – is a conductor that does not normally carry
current (except under fault conditions) and is also connected to earth. It is used to con-
nect the exposed metal surfaces of electrical equipment together and then to ground.
Examples are the bare copper conductor in non-metallic sheathed cable (romex
®
)
and the green, insulated conductor in power cords in portable equipment. These
equipment-grounding conductors help to prevent electric shock and allow over-current
devices to operate properly when ground faults occur. The size of this conductor should
be coordinated with the size of the over-current devices involved.
A “grounding electrode” – is the metallic device that is used to make actual contact with
the earth. other types of grounding electrodes include metal water pipes and metal
building frames.
A “grounding electrode conductor” – is the conductor between a common single
grounding point in the system and the grounding electrode.
“Bond” – refers to the connection between the “grounded conductor”, the “equip-
ment grounding” conductors and the “grounding electrode” conductor. bonding is also
used to describe connecting all of the exposed metal surfaces together to complete the
equipment- grounding conductors.
seCtIOn 4 |
AC Power Distribution & Grounding
Summary of Contents for PSE-12125A
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