Abstract

Loose neutrals represent one of the most hazardous and subtle single-phase service issues encountered by utility power quality (PQ) engineers. The condition arises when the neutral conductor connecting the center tap of a distribution transformer to the service entrance becomes resistive, unstable, or fully-open. When this occurs, the resulting unbalanced voltage that the customer receives can lead to erratic load operation, premature equipment failure, and in severe cases- fire or electrocution hazards. This paper describes the electrical mechanisms that cause loose neutrals, the visual signatures they produce, and detection methods. Using PQ Canvass you can take a deep dive into detecting loose neutrals with tools such as the loose neutral report, waveform capture, and particularly the RMS capture view to verify loose neutral conditions in the field.