Chapter A General rules of electrical installation design

G - Sizing and protection of conductors
Fig. G10 : Examples of methods of installation (part of table 52-3 of IEC 60364-5-52) (continued on next page)
2 Practical method for determining
the smallest allowable crosssectional
area of circuit conductors
Examples of wiring systems and reference methods of
installations
An illustration of some of the many different wiring systems and methods of
installation is provided in Figure G10.
Several reference methods are defined (with code letters A to G), grouping
installation methods having the same characteristics relative to the current-carrying
capacities of the wiring systems.
Item No. Methods of installation Description Reference method of
installation to be used to
obtain current-carrying
capacity
1 Insulated conductors or single-core
cables in conduit in a thermally
insulated wall
A1
Room
2 Multi-core cables in conduit in a A2
thermally insulated wall
4 Insulated conductors or single-core B1
cables in conduit on a wooden, or
masonry wall or spaced less than
0,3 x conduit diameter from it
5 Multi-core cable in conduit on a B2
wooden, or mansonry wall or spaced
less than 0,3 x conduit diameter
from it
20 Single-core or multi-core cables: C
- fixed on, or sapced less than 0.3 x cable
diameter from a wooden wall
30 On unperforated tray C
0.3 De
0.3 De
Room
Schneider Electric - Electrical installation guide 2008
G9
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