3-Phase 4 Wire Meters with CT and MD

If load is commonly more than 50 A, CT operated meters should be used. It is to be remembered that CTs should be properly selected for accurate recording. Commonly rating of CTs should fall inside 50 to 80 percent of the maximum load current of the consumer.

For two part tariff, meters having recording arrangement for maximum demand in kVA are to be given. The maximum demand (MD) indicators are additional mechanism attached to the meters to record the rate of consumption over a fixed period (commonly half an hour) every time and then get reset along with the help of a time switch. A pointer denoting the highest ever rate of consumption therefore recorded through the MD indicator is left behind, that has to be manually reset although taking down the reading each month.