Many sceptics thought it was impossible to achieve NMI Approval for a Multifunction Electricity Meter designed in a compact DIN rail footprint. In fact many doomsday forecasters predicted electrical switchboard enclosures, distribution boards, riser/cupboard spaces for multifunction metering would have to be increased in size to accommodate larger electrical metering to be in compliance for Energy Meters per NMI M 6-1.
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One of the many technical and metrology requirements for obtaining pattern approval and verification from The National Measurement Institute (NMI) for any active-energy electricity meter to be used for trade is for the energy meter to pass the 12KV impulse test.
Electricity meters, energy meters, multi-function metering and any power metering incorporating internal clocks for date/time stamp resolution must comply with NMI electrical metering standards to ensure the clock time does not drift.
