Verification of measuring instruments and measurement standards is an activity of assessing and certifying metrological technical characteristics of measuring instruments according to metrological technical requirements.
The measuring instruments of group 2 must be tested initially before being put into use, periodically during use, and after repair. Group 1 measuring instruments are tested voluntarily at the request of relevant organizations and individuals.
Group 1 measuring instruments are measuring instruments not on the list of group 2 measuring instruments.
+ Single phase AC meter
+ 3-phase AC meter
+ Variable measuring current
+ Measurement transformer
+ Means of measuring insulation resistance
+ Means of measuring ground resistance
+ Means of measuring electrocardiogram
+ Means of measuring electroencephalogram
A Chau Electric Energy Joint Stock Company (ACEE) is an organization appointed to inspect measuring transformers and current transformers measuring voltage up to 38.5kV, current up to 5000A.