Measurement Uncertainty Evaluation and Calibration of Electrical Safety Analyzer for Biomedical Equipment

Abstract

Calibration of electrical safety analyzers (ESA) are critical for ensuring the safety of medical electrical equipment (MEE) such as syringe pumps, defibrillators, and electrosurgical units, as per international and national standards. Accurate calibration traceable to the international system of units (SI) is essential to validate the safety parameters measured by ESAs. This paper presents the estimation of the measurement uncertainty for the calibration of ESAs for the electrical parameters essential in performing the electrical safety testing on the medical electrical equipment. The uncertainty of the relevant parameters, (i) Resistance (1 Ω) in protective earth resistance test mode, (ii) AC voltage (1–250 V) in point-to-point test mode (iii) DC (10 µA-6.5 mA) & AC current (1000 µA -6.5 mA) in leakage current test mode and related sub modes, (iv) Insulation resistance voltage (250 V & 500 V) and (v) Insulation resistance (0.5–90 MΩ) in insulation resistance test modes and associated sub modes is evaluated and the expanded uncertainty evaluated is 0.001 Ω, 0.1 V, 0.1 µA to 0.01 mA, 1 µA to 0.01 mA, 0.01 V and 0.1 MΩ- 0.4 MΩ respectively. The electrical safety testing has been conducted on key biomedical equipment such as neonatal intensive care incubator, defibrillator and infusion pump and their electrical safety parameters measured using calibrated ESA have been found to be in concurrence with the international electrotechnical commission (IEC) 60601–1.