IEC 61496-3 specifies additional requirements for the design, construction and testing of non-contact electro-sensitive protective equipment (ESPE) designed specifically to detect persons as part of a safety related system, employing active opto-electronic protective devices responsive to diffuse reflection (AOPDDRs) for the sensing function. Special attention is directed to requirements which ensure that an appropriate safety-related performance is achieved. An ESPE may include optional safety-related functions, the requirements for which are given both in Annex A of this part and in Annex A of IEC 61496-1. The important changes and improvements compared to the first edition of this part of the standard are: - extension of the range of detection capability covered by this part of the standard from 50 mm to 100 mm to the range of 30 mm to 200 mm; - clarification of requirements for the selection of multiple detection zones (Clause A.10); - more detailed information about the use of an AOPDDR as a whole body trip device by extension of Clause A.12 and a new Clause A.13; - improved description of the relationship between ranging accuracy and probability of detection (Annex BB).