Switchgear assemblies standards

The procedure for testing will be the same as that discussed for switchgear assemblies in Section 14.3.4. The impulse test voltage is applied as in Table 32.1(A) for series I and Table 32.2, for series II voltage systems with a full wave standard lightning impulse of 1.2/50 (Section 17.6.1). There should be no disruptive discharge or insulation breakdown. 

The main EC standard for low voltage switchgear assemblies is 1EC60439 which has seven parts. Part 1 covers the basic reqnirements for internal separation, compartments, barriers and partitions. It nses the IPXY notation of 1EC60529 as a basis for the ingress protection, mainly concentrating on X for access by tools, fingers, hands, small particles and dust. The minimum value of X used in... 

Switchgear and controlgear assemblies 13/345 Table 13.3 Standard insulation (impulse) levels for range II voltage systems (V , > 245 kV)... 

Circuits are controlled by switchgear which is assembled so that the circuit may be operated safely under normal conditions, isolated automatically under fault conditions, or isolated manually for safe maintenance. These requirements are met by good workmanship carried out by electrically skilled persons and the installation of approved British Standard materials such as switches, isolators, fuses or circuit-breakers (IET Regulation 131.1.1). The switchgear must also be non-combustible or housed in a non-combustible cabinet or enclosure (IET Regulation 421.1.200). The equipment belonging to the supply authority is sealed to prevent unauthorized entry, because if connection were made to... 

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