BS EN IEC 60305:2021 pdf free.Insulators for overhead lines with a nominal voltage above 1 000 V – Ceramic or glass insulator units for AC systems – Characteristics of insulator units of the cap and pin type.
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4 Mechanical characteristics, dimensions and types
String insulator units of the cap and pin type are standardized by the following specified characteristics:
— Specified electromechanical or mechanical failing load (SFL) according to IEC 60383-1;
— maximum nominal diameter of the insulating part;
— nominal spacing;
— minimum nominal creepage distance;
— standard coupling.
The corresponding values are indicated in Table 1, Table 2, Table 3, Table 4 and Table 5.
NOTE 1 The lollowing points merit attention for insulators for use in polluted areas;
a) even If the creepage distance is the same, the withstand voltage characteristics may change with shed shape of the insulators:
b) even if the string length Is the same, the withstand voltage characteristics may decrease with increasing insulator strength due to the lower efficiency of creepage distance for a larger average diameter,
NOTE 2 IEC 60815 gives details on the important parameters of shed profiles fur antipollution insulator5.
5 Designation and marking with respect to shed profile
Insulators are designated in Table 1, Table 2, Table 3. Table 4 and Table 5 by the letter U followed by a number indicating the specified electromechanical or mechanical failing load in kilonewtons.
The letter B or C which follows specifies a ball and socket or clevis and tongue, respectively. The following letter S or L. if present, specifies a short or long spacing.
The letter P. D, V. or T present for anti-fog proflle, “aerodynamics profile, two-alternating profile, or NthreealternatingN profile, as shown in Figure 1, Figure 2, Figure 3,Figure 4 and Figure 5, respectively.
IEC 60383-1 specifies that insulators shall be marked with the specified electromechanical or mechanical failing load. This load may be indicated by using the first part of the designation given in the first column of Table 1, Table 2, Table 3, Table 4 and Table 5: For instance, the insulator may be marked U 160 for the units U 160 BS, U 160 BL and U 160 BLP.BS EN IEC 60305 pdf free download.