Normal, Abnormal & Fault conditions rationalized; providing proper protection in equipment

Abstract

IEC standards developed over the last 75 years have not consistently used the terms Normal, Abnormal and Fault conditions in describing under what conditions a product needs to continue to operate safely. This paper rationalizes operating conditions across these modes and provides more consistency in the design and evaluation process, separating the responsibilities of the manufacturer and the installation. Product safety standards committees updating their documents in light of this work will be on a better footing for reliably safe products in the field.