This Standard applies to air-break switches, air-break disconnectors, air-break switch-disconnectors ana fuse-com bination units to be used in distribution circuits and mctor cir cuits the rated voltage of which does not exceed 1 000 V a. c. or 1 200 V d. c.
Motes \.— Depending on its design, a switch (or disconnector) can be referred to as "rotary switch (disconnector)', "camoperated switch (disconnector)", 'knife-switch (disconnector)", etc.
2.—If they are not manually operated, switches and dis connectors may have to comply with additional re quirements.
Any fuses incorporated shall conform to the requirements laid down in the relevant Pakistan Standard.
This Standard does not apply to equipment coming within the scope of Pakistan Standards on "Circuit-breakers", "Con tactors","Motor Starters" and "Control switches", however, when switches and fuse-combination units coming into the scope of this Standard are normally used to start, accelerate and/or stop a motor, they shall also comply with the additional requirements given in Appendix C
(1) PS : 1532 Circuit-breakers.
(2) IEC : 158-1—Contactors.
(3) IEC : 292-1——Motor starters.
(4) PS : 1300 and 1301 Control switches.
This Standard does not include the additional requirements necessary for electrical apparatus for explosive gas atmospheres.
Notes 3.— In this Standard, the word" switch"also applies to the apparatus referred to in French as "commu-tateurs",intended to modify the connections between several circuits, and inter alia to substitute a part of a circuit for another.
4.—As a general rule, in the rest of this Standard, switches, disconnectors, switch-disconnectors and fuse-com bination units will be referred to as "equipment".
1.2 Object :
The object of this Standard is to state :
(i) the characteristics of the equipment ;
(2) the conditions with which the equipment must comply with reference to :
(a) operation and behaviour in normal service,
(b) operation and behaviour in case of specified ab normal conditions, e. g. short-circuit ;
(c) dielectric properties ;
PS 1531-1982 history
1982PS 1531-1982 SPECIFICATION FOR LOW-VOLTAGE AIR-BREAK SWITCHES, AIR-BREAK DISCONNECTORS. AIR-BREAK SWITCH-DISCONNECTORS AND FUSE-COMBINATION UNITS