Abstract :
NAMAS AC voltage accreditations have evolved progressively in the last twenty five years. For the majority of this time NAMAS accreditations have relied on one or two well known AC-DC Thermal Transfer Standards. However in recent years Electronic Reference Standards have been developed and the previous monopoly of thermal transfer standards is now challenged. Improved uncertainties of measurement are being sought from the National Physical Laboratory (NPL) by NAMAS accredited laboratories so that they can improve their capabilities
