This Standard sets out the requirements for electrical installations in those patient treatment areas of hospitals and other medical and dental practices in which the administration or practitioner has elected to-(a) use medical electrical equipment during cardiac procedures; or(b) use medical electrical equipment with Type B (unprotected) applied parts during body type procedures; or(c) use multiple pieces of medical equipment with Type BF applied parts during body type procedures.The requirements are applicable to the electrical installations and certain conductive items in those areas.This Standard sets out additional requirements for electrical installations in patient treatment areas in hospitals and other medical and dental practices in New Zealand (see Appendix J). Patient treatment areas other than body-protected electrical areas or cardiac-protected electrical areas are not covered by this Standard, but are covered by the relevant requirements of AS 3000.NOTES:1 Attention is drawn to AS/NZS 2500, which outlines the method of determining the classification of various procedures and recommends routine operational and maintenance procedures to ensure the safe use and interconnection of medical electrical equipment. That Standard also explains how several procedures commonly carried out in a general ward area are classified under certain conditions as cardiac-type procedures warranting extreme caution.2 A rationale for the requirements of this Standard is given in Appendix A.3 If a hospital or medical practice has elected to undertake cardiac-type procedures then appropriate cardiac-protected electrical areas need to be provided.4 The number and disposition of cardiac-protected electrical areas that should be provided will be dependent on the types of procedures that the hospital or medical practice has elected to undertake.5 Hospitals and medical practices that might not propose to undertake cardiac-type procedures may, in the case of emergency, temporarily upgrade an area in accordance with the recommendations and limitations identified in AS/NZS 2500, to provide temporary electrical protection.6 The increasing use and application of medical electrical equipment in medicine and the range of electrical protection provided by such equipment, ranging from no isolation to full isolation, makes it difficult to determine which patient treatment areas will require cardiac-type or body-type electrical protective measures in the electrical installation. It is therefore recommended that, during any electrical installation in patient treatment areas-(a) close attention be given to the relevant requirements herein (earthing, subcircuit layout and other factors) that will facilitate conversion of areas to either body-protected or cardiac-protected areas;(b) attention be given to the recommendations of AS/NZS 2500 listing the electrical supply and equipment protective measures appropriate for particular medical procedures; and(c) consideration be given to residual current device (RCD) protection of other patient treatment areas where equipment to be used will be likely to be subjected to spilling or splashing of liquids. Areas such as dialysis rooms should always be wired as body-protected electrical areas because of the presence and likely spillage of copious amounts of liquid.7 It is important for hospital managements and the electrical design engineers to evaluate jointly the elected procedures likely to be undertaken and to determine which areas of the installation should be wired as body-protected electrical areas or as cardiac-protected electrical areas.8 Requirements for mobile trolleys supporting electrical equipment are given in AS/NZS 3200.1.0 and AS/NZS 4510.9 Requirements for emergency lighting are given in AS/NZS 2293.10 Requirements for emergency power systems in hospitals are given in AS/NZS 3009.