ZEC-503 insulating oil dielectric strength tester is a high-precision, fully digital industrial instrument. It adopts large-capacity single-chip microcomputer control, which is stable and reliable. The instrument is equipped with temperature and humidity and clock display functions, and is equipped with ground alarm function to remind customers to pay attention to safety. The instrument program has GB1986, GB2002 two national standard methods and custom operation, which can meet the needs of different users. The instrument oil cup adopts special glass once cast molding, which eliminates the occurrence of oil leakage and other interference phenomena. The instrument's unique high-pressure end sampling design makes the test values more accurate and reliable.