Page 198 - Electrical Safety of Low Voltage Systems

CHAPTER11

Earth Electrodes,

Protective

Conductors, and

Equipotential

Bonding Conductors

The heating of a conductor depends upon its
resistance and the square of the current passing
through it. james p. joule

11.1 Introduction
Earth electrodes, protective conductors (PE), and equipotential bond-
ing conductors, both main (MEB) and supplementary (SB), are the
fundamental components of the earthing arrangements. A failure in
any of these elements can compromise the electrical safety of the in-
stallation as well as its functionality. Earthing arrangements, in fact,
may be used for both functional reasons (e.g., system grounding) and
safety purposes (e.g., grounding of ECPs in TT systems, bonding of
ECPs in TN systems).
Figure 11.1 summarizes the roles of the aforementioned elements
in the earthing arrangements.

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