JDG4-0.5 series voltage transformers are dry type insulation, two coils, in house installation and single phase. Adapted to 50/60Hz, rated voltage 0.5kV low voltage power system, as voltage and power metering and relay protection. Marks on the terminals as A and N for primary, a and n for secondary. When the primary is live, the secondary coli cannot have short circuit, or that the transformer will be burnt.