ELECTROMAGNETIC COMPATIBILITY (EMC) - TECHNICAL REPORT - TYPE 3 - INSTALLATION AND MITIGATION GUIDELINES - EARTHING AND CABLING
International Electrotechnical Committee
FOREWORD
INTRODUCTION
1 Scope
2 Reference documents
3 Definitions
4 General EMC considerations on installation of
earthing and cabling systems
4.1 General
4.2 EMC and safety (insulation) installation
requirements
4.3 Equipment and installation ports
5 Earthing and bonding
5.1 Requirements concerning safety
5.2 Requirements concerning EMC
5.3 Design of the earthing system
6 Bonding
6.1 General
6.2 Bonding straps
6.3 Connections
6.4 Bonding of specific equipment
6.5 Procedures for users
7 Cables and wires
7.1 General
7.2 Differential and common mode circuit, transfer
impedance Zt
7.3 Set of EMC rules for cable and wire installation
7.4 Types of cables and their use with regard to
EMC
7.5 Types of parallel-earthing conductor (PEC)
7.6 Connecting and earthing of cables and parallel
earthed conductors
7.7 General routing of cables
7.8 Cable bundles
7.9 Cables serving power ports
7.10 Cables serving signal and control ports
8 Additional interference mitigation methods
8.1 Common-mode ferrite choke
8.2 Electrical separation
9 Measuring and testing methods
9.1 Earthing and bonding
9.2 Cables and installation
Figures
1 Demonstration of the fallacy of the 'equipotentiality'
concept as a universal rule
2 Schematic plan view of a typical earth electrode
3 Misconception of 'dedicated', 'independent', or
'isolated' earth electrodes
4 The concept of a single earth electrode
5 Recommended configuration for the earth electrodes
and earthing network
6 Loops involving signal cables and earthing network
7 A three-dimensional schematic of the recommended
approach for the earthing network
8 General principles for bonding of various apparatus
or systems to the earthing network
9 Simplified representation of a bonding strap
10 A more realistic representation of an installed
bonding strap
11 Typical bonding straps
12 Relative inductance of flat and round conductors
13 Relative inductance of round, flat and double
bonding straps
14 Example of protected removable connection of a bonding
strap
15 Example of optimal bonding of a shielded cable to the
enclosure
16 Schematic of interconnected chassis
17 Differential mode and common mode circuits with
bonding strips and signal cables
18 Effect of the configuration of a parallel-earthing
conductor on the transfer impedance
19 Slits in conduits and cable trays
20 Recommended configuration for cable trays with branches
21 Recommended cable positions parallel to an
H-shaped beam from the EMC point of view
22 Penetration of a shielded cable through an
enclosure wall
23 Tray with partition
24 Example of stacking for conduits or trays
25 Topology of circuits containing switches
26 Undesirable connection of a coaxial cable
27 Typical implementations of common-mode ferrite chokes
28 Limitations in the effectiveness of an isolation
transformer
29 Parasitic coupling at high frequencies
Annexes
A Examples of earthing systems and cable implementation
B Applying cable theory to enhance EMC
C Benefits of additional conductors parallel to a
cable
D Bibliography
Annex figures
A.1 Example of topology for a hybrid earthing system
A.2 EMC cabinet for the protection of sensitive
electronics
A.3 Earthing system for a drive with converter and
associated electronics
A.4 Earthing configuration for a power supply system with
associated electronics
A.5 Initial arrangement of the power and control cables
A.6 Improved design with appropriate shield connections
B.1 Unbalanced transport of signals
B.2 Behaviour of Zt as function of frequency for several
coaxial cable configurations
B.3 Unbalanced transmission system connected to earth
at one end
B.4 Balanced transmission system
B.5 Current paths in a coaxial cable
B.6 Differential-mode voltage induced by a magnetic
field in a cable with braided shield
B.7 Currents in the outer conductor of a coaxial cable
B.8 A two-lead cable perturbed by a nearby lead at
the voltage Uext
C.1 Coaxial cables with parallel-earthing conductors
C.2 A coaxial with two outer conductors
C.3 Transfer impedances in a shielded balanced pair
C.4 Example of transfer impedance for an aluminium
conduit as a function of frequency
C.5 Mutual inductance and magnetic field for a conduit or
cable tray
C.6 Insulated covers over a conduit
Gives guidelines for earthing and cabling of electrical and electronic systems and installations aimed at ensuring electromagnetic compatibility (EMC) among electrical and electronic apparatus or systems. Addresses earthing practices and with cables used in industrial, commercial and residential installations. Intended to be used by installers and users and manufacturers of sensitive electrical or electronic installations and systems, and equipment having high emission levels for degrading the overall electromagnetic (EM) environment. Mainly applicable to new installations, but may apply to extensions or modifications to existing facilities.
| Document Type | Standard |
| Status | Current |
| Publisher | International Electrotechnical Committee |
| Committee | TC 77B |
