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AC POWER DISTRIBUTION AND GROUNDING
CAUTION!
PLEASE NOTE THAT THE DC INPUT CONNECTIONS ON THIS
INVERTER ARE NOT CONNECTED (BONDED) TO THE METAL
CHASSIS OF THE INVERTER. BOTH THE INPUT AND OUTPUT
CONNECTIONS ARE ISOLATED 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
connected 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
current 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
connect 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 “equipment
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.
