Code of Practice 5 defines the minimum requirements for the Metering Equipment required for the measurement and recording of electricity transfers at Defined Metering Points where the Maximum Demand does not exceed 1MW.
Current Transformers
Where required, one set of current transformers to IEC Standard 185 with a minimum standard of accuracy to Class 0.5, shall be provided per circuit. Preferably, the current transformers shall be dedicated for Settlement purposes, but the CTs may be used for other purposes provided the overall accuracy requirements are met.
However, it may be easer to add a second set of CT’s for other functional measuring use, than to demonstrate overall accuracy of revenue metering remains intact.
Where CT test certificates are not available and the CTs can be verified as class 0.5 or better and are installed on an LV installation, the extreme errors for the accuracy class shall be assumed.
Voltage Transformers
Where required a voltage transformer to IEC Standard 186 with a minimum standard of accuracy to Class 1 shall be provided for the metering of a circuit.
Similar to CTs, VT’s can be used for other purposes but need to demonstrate overall accuracy of revenue metering remains intact.
But, it may be easer to add a second set of VT’s for other functional measuring use, than to demonstrate overall accuracy of revenue metering remains intact.
Remember similar to Cop5 CT’s, they are effectively adopted by the MOP and sealed to prevent customer tampering etc.
