BS EN 60156:1996

Introduction
1 Scope
2 Normative references
3 Electrical apparatus
3.1 Voltage regulator
3.2 Step-up transformer
3.3 Current-limiting resistors
3.4 Switching system
3.5 Measuring device
4 Test assembly
4.1 Test cell
4.2 Electrodes
4.3 Stirring (optional)
5 Preparation of electrodes
6 Test assembly preparation
7 Sampling
7.1 Sample containers
7.2 Sampling techniques
8 Condition of the sample
9 Test procedure
9.1 Sample preparation
9.2 Filling of the cell
9.3 Application of voltage
10 Report
11 Test data dispersion
Figures
Annex
ZA (normative) Normative references to international
      publications with their corresponding European
      publications

The test method applies to all types of insulating liquids of nominal viscosity up to 350 mm²s$u-¹ at 40°C. It is appropriate both for acceptance testing on unused liquids at the time of their delivery and for establishing the condition of samples taken in monitoring and maintenance of equipment.

This International Standard specifies the method for determining the dielectric breakdown voltage of insulating liquids at power frequency. The test portion, contained in a specified apparatus, is subjected to an increasing a.c. electrical field by means of a constant rate of voltage rise until breakdown occurs.

The method applies to all types of insulating liquids of nominal viscosity up to 350 mm² s^–1 at 40 °C. It is appropriate both for acceptance testing on unused liquids at the time of their delivery and for establishing the condition of samples taken in monitoring and maintenance of equipment.