Switchgear assemblies power frequencies

Verification of dielectric properties, limited to power frequency voltage withstand test. This test is neither mandatory nor recommended, but may be required if a modification is carried out in the switchgear assembly at site. 

Insulation levels, power frequency and impulse withstand voltages for metal-enclosed switchgear assemblies... 

Wet test While an indoor type switchgear assembly requires only a dry power frequency voltage withstand test, the outdoor type switchgear assembly also needs a wet test under wet conditions to check the external insulation. For the test procedure refer to lEC 60060-1. 

Field tests Power frequency withstand test on the primary windings (for un-grounded VTs). The value of the test voltage and the test procedure, is almost the same as that for a switchgear assembly (Section 14.5). 

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