AS NZS 3003 1999 electrical installations

Title AS/NZS 3003:1999 Electrical installations - Patient treatment areas of hospitals and medical and dental practices Licensee Licensed to LUU MINH LUAN on 25 Feb 2002 Conditions of use This is a licensed electronic copy of a document where copyright is owned or managed by Standards Australia International Your licence is a single user licence and the document may not be stored, transferred or otherwise distributed on a network You may also make one paper copy of this document if required Web Check-up AS/NZS 3003:1999 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited Australian/New Zealand Standard™ Electrical installations—Patient treatment areas of hospitals and medical and dental practices AS/NZS 3003:1999 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee HT/21, Wiring of Medical Treatment Areas in Hospitals It was approved on behalf of the Council of Standards Australia on 23 November 1998 and on behalf of the Council of Standards New Zealand on December 1998 It was published on February 1999 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The following interests are represented on Committee HT/21: Association of Consulting Engineers, Australia Australian Chamber of Commerce and Industry Australian Dental Association Australian Federation for Medical and Biological Engineering Australian Nursing Federation Australian Private Hospitals Association Australian Society of Anaesthetists Biomedical Engineering Advisory Group SA Canterbury Area Health NZ College of Biomedical Engineering Institution of Engineers Australia Department of Public Works and Services NSW Electricity Supply Association of Australia Health Department, WA Institute of Hospital Engineering (Australia) Medical Industry Association of Australia Ministry of Commerce, NZ NSW Health Department National Electrical Contractors Association of Australia Royal Australasian College of Physicians South Australian Health Commission Review of Standards To keep abreast of progress in industry, Joint Australian/ New Zealand Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary It is important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto Full details of all Joint Standards and related publications will be found in the Standards Australia and Standards New Zealand Catalogue of Publications; this information is supplemented each month by the magazines ‘The Australian Standard’ and ‘Standards New Zealand’, which subscribing members receive, and which give details of new publications, new editions and amendments, and of withdrawn Standards Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed Notification of any inaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be made without delay in order that the matter may be investigated and appropriate action taken This Standard was issued in draft form for comment as DR 94087 AS/NZS 3003:1999 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited Australian/New Zealand Standard™ Electrical installations—Patient treatment areas of hospitals and medical and dental practices First published as part of AS 3003 — 1996 Second edition 1985 Jointly revised and redesignated, in part, AS/NZS 3003:1999 Published jointly by: Standards Australia The Crescent, Homebush NSW 2140 Australia Standards New Zealand Level 10, Radio New Zealand House, 155 The Terrace, Wellington 6001 New Zealand ISBN 7337 2479 AS/NZS 3003:1999 PREFACE This Standard was prepared by the Committee HT/21, Wiring of Medical AS 3003 — 1985 It specifies special treatment areas of hospitals These AS 3000, SAA Wiring Rules Joint Standards Australia/Standards New Zealand Treatment Areas in Hospitals, to supersede, in part, requirements for electrical installations in patient requirements are additional to those specified in This Standard encourages reference to AS/NZS 2500, Guide to the safe use of electricity in patient care, and particularly the flow chart included therein, to enable the level of electrical supply protection necessary to be determined by evaluating the type of procedures to be undertaken in a particular area and the type of equipment used Treatment areas in which medical electrical procedures are to be electively undertaken can then be identified and wired as body-protected electrical areas or cardiac-protected electrical areas to provide the necessary level of electrical shock protection in the mains supply wiring and, where appropriate, earthing systems Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The earliest consultation between hospital management and the electrical design engineers is recommended, to jointly evaluate the elected procedures likely to be undertaken, in order to determine which areas of the hospital or medical or dental practice should be wired as body-protected electrical areas or as cardiac-protected electrical areas This Standard is intended to apply only to installations (or alterations or additions thereto) made or carried out after the date on which the Standard is published However, it is strongly recommended that hospital managements carefully evaluate the procedures undertaken within existing installations, and that they take steps to implement the appropriate electrical safety requirements specified herein for areas that are used for cardiac-type procedures or for procedures involving the regular use of medical electrical equipment While the Standard is intended to apply to new installations or extensions, some guidance is given concerning conversion of older installations Changes to the 1985 edition include the following: (a) Revision of the definitions of body-protected and cardiac-protected areas (b) Introduction of the term ‘leakage protected circuit’ to describe a circuit protected by a residual current device or an isolated electrical supply (c) Introduction of the term ‘leakage protective device’ to describe either a residual current device or an isolated electrical supply (d) Introduction of requirements for earth leakage protection for socket-outlets which are outside the defined protected electrical areas but which would normally be expected to be used to power equipment located within the area (e) Removal of the requirements for access to overcurrent protective devices (f) The number of socket-outlets at patient locations no longer mandated (g) Inclusion of requirements for socket-outlets intended for cleaning purposes (h) Removal of requirements for the design, construction and testing of isolated electrical supplies and their relocation in AS/NZS 4510 (i) The revised presentation information on testing and commissioning in a more logical sequence for the convenience of persons carrying out the tests (j) Alterations to the requirements relating to equipotential earthing systems in cardiac-protected areas AS/NZS 3003:1999 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the appendix to which they apply A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance © Copyright STANDARDS AUSTRALIA / STANDARDS NEW ZEALAND Users of Standards are reminded that copyright subsists in all Standards Australia and Standards New Zealand publications and software Except where the Copyright Act allows and except where provided for below no publications or software produced by Standards Australia or Standards New Zealand may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia or Standards New Zealand Permission may be conditional on an appropriate royalty payment Australian requests for permission and information on commercial software royalties should be directed to the head office of Standards Australia New Zealand requests should be directed to Standards New Zealand Up to 10 percent of the technical content pages of a Standard may be copied for use exclusively in-house by purchasers of the Standard without payment of a royalty or advice to Standards Australia or Standards New Zealand Inclusion of copyright material in computer software programs is also permitted without royalty payment provided such programs are used exclusively in-house by the creators of the programs Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standard is amended or revised The number and date of the Standard should therefore be clearly identified The use of material in print form or in computer software programs to be used commercially, with or without payment, or in commercial contracts is subject to the payment of a royalty This policy may be varied by Standards Australia or Standards New Zealand at any time AS/NZS 3003:1999 CONTENTS Page SECTION SCOPE AND GENERAL 1.1 SCOPE 1.2 APPLICATION 1.3 REFERENCED DOCUMENTS 1.4 DEFINITIONS 1.5 METHOD OF MARKING 11 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited SECTION GUIDANCE 2.1 INTRODUCTION 13 2.2 AREA SELECTION 13 2.3 CLASSIFICATION SELECTION 14 SECTION BODY-PROTECTED ELECTRICAL AREAS 3.l GENERAL 3.2 SUPPLY WIRING 3.3 EARTHING 3.4 ACCESS TO LEAKAGE PROTECTIVE DEVICES AND ISOLATION MONITORS 3.5 SOCKET-OUTLETS 3.6 RESIDUAL CURRENT DEVICES (RCDs) 3.7 LOW VOLTAGE ISOLATED SUPPLIES 3.8 ISOLATING SWITCHES 3.9 MARKING 3.10 COMMISSIONING LINE 15 15 16 SECTION CARDIAC-PROTECTED ELECTRICAL AREAS 4.l GENERAL 4.2 SUPPLY WIRING 4.3 EARTHING 4.4 ACCESS TO LEAKAGE PROTECTIVE DEVICES AND LINE ISOLATION MONITORS 4.5 SOCKET-OUTLETS 4.6 RESIDUAL CURRENT DEVICES (RCDs) 4.7 ISOLATED SUPPLIES (OTHER THAN ELV) 4.8 ISOLATING SWITCHES 4.9 MARKING 4.10 COMMISSIONING APPENDICES A RATIONALE FOR THE REQUIREMENTS OF THIS STANDARD B PLANNING OF AREAS C MARKING OF BODY-PROTECTED ELECTRICAL AREAS AND CARDIAC-PROTECTED ELECTRICAL AREAS D COMMISSIONING TESTS FOR BODY-PROTECTED ELECTRICAL AREAS AND CARDIAC-PROTECTED ELECTRICAL AREAS 16 16 17 18 19 19 19 20 20 22 29 29 30 31 32 32 32 33 38 42 43 AS/NZS 3003:1999 Page E F G H Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited I J MEASURES FOR AVOIDING INTERFERENCE FROM MAGNETIC FIELDS METHOD FOR MEASURING MAGNETIC FIELDS INSTRUMENT FOR MEASURING POTENTIAL DIFFERENCES IN AN INSTALLATION EARTHING OF PERMANENTLY WIRED ELECTRICAL EQUIPMENT IN EP AREAS CALCULATIONS FOR EQUIPOTENTIAL EARTHING SYSTEMS ADDITIONAL REQUIREMENTS FOR APPLICATION IN NEW ZEALAND 60 61 63 65 68 70 AS/NZS 3003:1999 STANDARDS AUSTRALIA / STANDARDS NEW ZEALAND Australian / New Zealand Standard Electrical installations — Patient treatment areas of hospitals and medical and dental practices S E C T I O N S C O P E A N D G E N E R A L 1.1 SCOPE 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 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited (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: 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 A rationale for the requirements of this Standard is given in Appendix A If a hospital or medical practice has elected to undertake cardiac-type procedures then appropriate cardiac-protected electrical areas need to be provided 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 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 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; COPYRIGHT AS/NZS 3003:1999 (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 bodyprotected electrical areas because of the presence and likely spillage of copious amounts of liquid 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 Requirements for mobile trolleys AS/NZS 3200.1.0 and AS/NZS 4510 supporting electrical equipment are given in Requirements for emergency lighting are given in AS/NZS 2293 10 Requirements for emergency power systems in hospitals are given in AS/NZS 3009 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited 1.2 APPLICATION Electrical installations in body-protected or cardiac-protected electrical areas shall be carried out in accordance with the appropriate requirements of AS 3000 in Australia and the Electricity Regulations in New Zealand, and with the requirements of this Standard The requirements include the following: (a) (b) For body-protected and cardiac-protected electrical areas (i) Provision of protected power supplies (ii) On isolated circuits, switching in all live conductors, of socket-outlets and permanently wired equipment For cardiac-protected electrical areas (i) Additional earthing requirements (ii) In Australia, modified resistance of socket-outlet earthing contacts (iii) Insulation of earthing connections (iv) Particular requirements for the ‘looping in’ of earthing conductors (v) Extra-low voltage (ELV) supply requirements This Standard applies to those installations (or alterations or additions thereto) made or carried out after the date of publication of this Standard However, hospital management should carefully evaluate the procedures electively undertaken within existing hospitals and take steps to implement the requirements specified herein for the appropriate class of area 1.3 REFERENCED DOCUMENTS Standard: AS 1125 The following documents are referred to in this Conductors in insulated electric cables and flexible cords 1169 Minimizing of combustion hazards arising from the medical use of flammable anaesthetic agents 1319 Safety signs for the occupational environment 2293 2293.1 Emergency evacuation lighting for buildings Part 1: System design, installation and operation 3000 Electrical installations — Buildings, structures and premises (known as the SAA Wiring Rules) COPYRIGHT AS/NZS 3003:1999 58 D4 RCD COMMISSIONING TEST RESULTS as follows: An example of an appropriate form is INSTITUTION LOCATION Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited Circuit No Minimum trip current test Trip time for 10-milliampere fault, ms Test Test Test TESTED CHECKED DATE DATE COPYRIGHT Test Test Test 59 AS/NZS 3003:1999 D5 LIM COMMISSIONING TEST RESULTS as follows: Circuit No Prospective hazard current, mA Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited Line Line An example of an appropriate form is Alarm current, mA Res fault Bal Cap fault Unbal Bal TESTED CHECKED DATE DATE COPYRIGHT Unbal 45 degree fault Bal Unbal AS/NZS 3003:1999 60 APPENDIX E MEASURES FOR AVOIDING INTERFERENCE FROM MAGNETIC FIELDS (Informative) E1 GENERAL Areas in which measurements of potential generated by the body are performed, e.g EEG and ECG rooms, should be protected against interference which might cause a dangerous situation for the patient or cause incorrect measurements NOTE: Adequate spacing is necessary between the equipment that may cause magnetic interference and the place for the examination of patients, and the following values of magnetic field strength should not be exceeded: (a) 0.38 µT p-p for ECG recording (b) 0.19 µT p-p for EEG recording Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The basis for these figures and a method for testing the magnetic field is given in Appendix F E2 LOCATION OF EQUIPMENT Equipment likely to generate strong stray magnetic fields, e.g transformers, motors, large power cables, ballasts of fluorescent lamps, should be installed so as to minimize the interference to equipment in the areas described in Paragraph E1 The following minimum distances between patient and equipment are recommended unless it can be shown that the limits in the Note to Paragraph E1 are not exceeded: (a) (b) Fixed wiring with considerable load (e.g lifts), as follows: (i) 50 A to 200 A m (ii) 200 A to 400 A m (iii) More than 400 A m Lamps and ballasts of fluorescent and discharge luminaires, as follows: (i) Up to ballasts m (ii) More than ballasts m E3 UNDERFLOOR HEATING Where electric underfloor heating is used, the following precautions should be taken to suppress the electrical and magnetic field it causes: (a) The supply should be direct current provided by a three-phase bridge rectifier circuit (b) The conductors should be laid bifilarly (c) The heating units should be screened on both sides by a magnetic-material fine mesh in foil or gauze form (e.g iron or steel) which, if accessible, should be connected to the equipotential junction COPYRIGHT 61 APPENDIX AS/NZS 3003:1999 F METHOD FOR MEASURING MAGNETIC FIELDS (Informative) During the recording of bioelectric potential such as those recorded by ECG or EEG equipment, interference can be caused by magnetic fields The magnitude of the interference depends upon the magnetic induction, the area of the loop consisting of the patient and the patient leads, and the sensitivity of the measuring equipment used The sensitivity of the measuring equipment (ECG, EEG) is determined by the equipment application, the area of the loop of the patient and the patient leads being relatively fixed The stray magnetic field, therefore, needs to be at a sufficiently low level to reduce the interference to an acceptable level The ECG or EEG serves as a measuring instrument With the leads of the instrument connected to a standardized test coil (see Figure F1), the a.c amplitude of the recorded signal corresponds to the strength of the magnetic field Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The design of such a standardized test coil for 50 Hz supply is based on the following values: (a) Maximum permissible interference voltage: ECG EEG 30 µV p-p µV p-p (b) Estimated loop area, consisting of patient and patient leads: ECG EEG 0.25 m2 0.05 m2 (c) Maximum permissible induction:* ECG EEG 0.38 µT p-p 0.19 µT p-p The test coil is designed for an output voltage of mV p-p at a magnetic induction of µT p-p With the standardized sensitivity of mV/10 mm amplitude of recorded electrocardiograph trace, induction of this magnitude will result in an amplitude of 10 mm p-p for the recorded interference trace The permissible amplitude of the interference signal trace is therefore — ECG EEG * Based on B = Ep p ωnA where B = magnetic induction, in teslas Ep-p = interference, in volts peak-to-peak ω = angular frequency = πf f = frequency = 50 Hz n = turns = A = area, in square metres COPYRIGHT 3.8 mm p-p 1.9 mm p-p AS/NZS 3003:1999 62 During the measurements the coil should be moved into all possible positions, and the largest trace excursion should be recorded Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The accuracy of the test device is approximately 10 percent Turn area Number of turns Wire diameter Average winding diameter DC resistance of winding Output voltage at µT 100 cm2 318 0.28 mm (AWG 29) 113 mm 32 Ω (approx.) mV NOTE: The values given apply only to a circular coil wound on a non-magnetic former The coil may also be designed in another shape, e.g square FIGURE F1 TECHNICAL DATA OF THE COIL FOR 50 Hz COPYRIGHT 63 APPENDIX AS/NZS 3003:1999 G INSTRUMENT FOR MEASURING POTENTIAL DIFFERENCES IN AN INSTALLATION (Informative) The measuring instrument should present a resistive load of approximately kΩ between its measuring terminals and should measure the r.m.s value, including d.c., of the current flowing through the kΩ load resistor It should be capable of reading up to 100 mV and should have a maximum error of mV Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited The frequency response of the instrument should be in accordance with Figure G1 NOTES: The frequency response of the measuring instrument should continue to d.c An example of such a measuring instrument is shown in Figure G2 The measuring device specified in AS 3200.1 may be used for this measurement FIGURE G1 FREQUENCY RESPONSE CHARACTERISTIC OF MEASURING INSTRUMENT COPYRIGHT Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited AS/NZS 3003:1999 64 NOTES: The frequency response of the instrument cannot be obtained by simply bypassing a kΩ resistor with an appropriate capacitor because the instrument should have the specified frequency response characteristic, whether measuring current from a high impedance or a low impedance source The effective capacitance to earth of the measuring instrument should be low so that the accuracy of the measuring instrument will comply with the requirements, even when measuring current at a common mode voltage of 265 V, as required in AS 3200.1.0 This may be achieved with low real capacitance to earth, or by guard shielding FIGURE G2 TYPICAL MEASURING INSTRUMENT COPYRIGHT 65 APPENDIX AS/NZS 3003:1999 H EARTHING OF PERMANENTLY WIRED ELECTRICAL EQUIPMENT IN EP AREAS (Normative) H1 GENERAL This Appendix specifies the requirements for the earthing of permanently wired electrical equipment which is installed in the EP area of cardiac-protected electrical areas and which incorporates LV or ELV supply wiring The requirements specified herein include the interconnection and earthing of accessible conductive parts of equipment powered from various types of power supplies Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited NOTE: An illustration of the rationale for the requirements of this Appendix is given in Figure H1 FIGURE H1 RATIONALE FOR EARTHING OF EXAMINATION LIGHTS AND OPERATING THEATRE LIGHTS IN EP AREAS COPYRIGHT AS/NZS 3003:1999 H2 66 EQUIPMENT POWERED FROM DOUBLE-INSULATED* ELV SUPPLIES H2.1 General The requirements of this Paragraph apply to equipment which is powered from an external ELV d.c supply complying with Clause 4.2.3 H2.2 Interconnection of accessible conductive parts Where conductive parts of the equipment are accessible within the EP area and are single-insulated from ELV conductors within the equipment, such parts shall be connected together and to a protective earthing terminal The resistance between each such part and accessible conductive parts shall be less than 0.1 Ω NOTE: Accessible conductive parts need not be connected together and the equipment need not be earthed if the accessible conductive parts are double-insulated from ELV conductors within the equipment Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited H2.3 Earthing Where the equipment is provided with a protective earthing terminal in accordance with Paragraph H2.2 and no accessible conductive parts are in direct contact with structural metal, the protective earthing terminal of the equipment shall be connected to the EP bus The resistance between the protective earthing terminal of the equipment and the following points shall be less than 0.1 Ω: (a) Earthing terminals of general purpose outlets (b) Earthing terminals of other fixed equipment (c) The EP junction Where accessible conductive parts of the equipment are in direct contact with structural metal, the mounting point/main earthing terminal of the equipment shall be connected directly to the EP junction The resistance between the mounting point/protective earthing terminal and the EP junction shall be less than 0.1 Ω H3 EQUIPMENT POWERED FROM SINGLE-INSULATED† ELV SUPPLIES A transformer which has not been approved to AS/NZS 3108 (and which may provide only functional insulation between the LV primary and the ELV secondary) may be used to supply fixed, ELV-powered equipment, provided that one of the following conditions applies — (a) To comply with the requirements of its approval and test specification, the equipment is treated as low voltage, a.c powered, Class I or Class II equipment, whether or not the transformer is mounted within the equipment (b) The equipment is treated as if it were powered from the same low voltage supply as the transformer (c) If the transformer is remote from the equipment, the wiring from the transformer to the equipment is insulated in accordance with AS 3000 for low voltage wiring The interconnection of accessible conductive parts and the earthing of the equipment shall be in accordance with either Paragraph H4 or Paragraph H5 A transformer which has not been approved to AS/NZS 3108 shall not be used to supply any type of socket-outlet * The term ‘double-insulated’ here refers to the insulation from the low voltage supply provided within the ELV transformer/supply It does not refer to the insulation between the ELV wiring and the accessible conductive parts of the fitting † The term ‘single-insulated’ here refers to the insulation from the low voltage supply provided within the ELV transformer/supply It does not refer to the insulation between the ELV wiring and the accessible conductive parts of the equipment COPYRIGHT 67 H4 AS/NZS 3003:1999 EQUIPMENT POWERED FROM PROTECTED LV SUPPLIES H4.1 General The requirements of this Paragraph apply to equipment which is powered from— (a) a low voltage a.c supply complying with Clause 4.2.1; or (b) a low voltage d.c supply complying with Clause 4.2.2 H4.2 Interconnection of accessible conductive parts Accessible conductive parts of Class I equipment other than those parts separated from live parts by double insulation shall be connected together and to a protective earthing terminal of the equipment The resistance between each such part and the protective earthing terminal shall be less than 0.1 Ω NOTE: These requirements are covered in AS/NZS 3100 Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited H4.3 Earthing Where the equipment is provided with a protective earthing terminal in accordance with Paragraph H4.2 and no accessible conductive parts of the equipment are in direct contact with structural metal, the protective earthing terminal of the equipment shall be connected to the equipotential earthing system The resistance between the protective earthing terminal and the following points shall be less than 0.5 Ω: (a) Earthing terminals of general purpose outlets (b) Earthing terminals of other fixed equipment (c) The EP junction Where any accessible conductive parts of the equipment are in direct contact with structural metal, the mounting point/protective earthing terminal shall be connected directly to the EP junction The resistance between the mounting point/protective earthing terminal of the equipment and the EP junction shall be less than 0.1 Ω H5 EQUIPMENT POWERED FROM UNPROTECTED LV SUPPLIES H5.1 General The requirements of this Paragraph apply to equipment which is powered from— (a) a low voltage a.c supply which does not comply with Clause 4.2.1; or (b) a low voltage d.c supply which does not comply with Clause 4.2.2 H5.2 Interconnection and earthing of accessible conductive parts of Class I equipment other than those parts separated from live parts by shall be interconnected and the equipment shall be earthed directly to The resistance between the following points and the EP junction shall be Conductive parts double insulation the EP junction less than 0.1 Ω: (a) Each conductive part of the fitting which is accessible within the EP area (b) The protective earthing terminal of the equipment NOTE: This requirement for interconnecting the accessible conductive parts is more stringent than those in AS/NZS 3100 The mounting point of Class II equipment which has conductive parts accessible within the EP area and in direct contact with structural steel shall be connected directly to the EP junction COPYRIGHT AS/NZS 3003:1999 68 APPENDIX I CALCULATIONS FOR EQUIPOTENTIAL EARTHING SYSTEMS (Informative) I1 REQUIREMENTS OF THE STANDARD Clauses 4.3.2.2, 4.3.2.4 and 4.3.2.5 specify the minimum resistance required for the equipotential earthing system I2 EXAMPLES OF RESISTANCE CALCULATIONS I2.1 General The conductor cross-sectional area required for a particular application may be calculated from tables of resistance in AS 1125, AS 3000, or AS/NZS 3008.1.1 and AS/NZS 3008.1.2 NOTE: Some figures derived from AS 1125 are given in Table Il Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited I2.2 Equipotential earthing system The cross-sectional area of an earthing conductor forming the equipotential earthing system will be determined by the distance between items (viz the EP junction, EP terminals, and earthing terminals of socket-outlets and permanently wired equipment) which are to be connected to it The most feasible route for the equipotential earthing system should be determined and the nominal cross-sectional area of the conductor selected so that the resistance between any two items does not exceed 0.1 Ω Table I1 gives the maximum lengths that yield a resistance of 0.1 Ω for earthing conductors of various sizes I2.3 Connections to the EP junction The cross-sectional area required for an earthing conductor connecting an item mentioned in Clause 4.3.2.4 to the EP junction will be determined by the distance between that item and the EP junction and whether the method chosen is direct connection or indirect connection The most feasible route for each connection should be determined and the nominal cross-sectional area of the conductor selected so that the resistance of the connection does not exceed that described in Clause 4.3.2.4 NOTE: Table I1 may be used for the determination of the maximum lengths that yield a resistance of 0.01 Ω for conductors of various sizes by dividing by 10 the length in Column COPYRIGHT 69 TABLE AS/NZS 3003:1999 I1 MAXIMUM LENGTH OF EARTHING CONDUCTORS TO GIVE 0.1 Ω RESISTANCE Nominal cross-sectional area Number and nominal diameter of wires in conductor * mm2 number/mm Maximum length of conductor to give 0.1 Ω resistance (single core plain annealed copper) † m 2.5‡ 7/0.67 7/0.85 7/1.04 13.7 22.1 33.1 10 16 7/1.35 7/1.70 55.8 88.4 * A single-stranded conductor is not permitted by AS 3000 A greater number of strands is permissible (see AS/NZS 3116 and AS 3147) † Based on an ambient temperature of 20°C Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited ‡ May be used only in circumstances permitted by AS 3000 COPYRIGHT AS/NZS 3003:1999 70 APPENDIX J ADDITIONAL REQUIREMENTS FOR APPLICATION IN NEW ZEALAND (Normative) JI SCOPE This Appendix sets out additional requirements for electrical installations in patient treatment areas of hospitals and other medical and dental practices in New Zealand J2 DEFINITIONS For the purpose of this Appendix the definitions below apply J2.1 Exposed conductive part — a fitting or part of a fitting made of conductive material that can be readily touched and is not a live part, but which may become alive under fault conditions Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited J2.2 Patient environment — a defined volume (see Figure J1) in which intentional or unintentional contact between a patient and parts of a medical electrical system or some other persons touching parts of the system can occur NOTE: This definition is comparable with that for patient equipotential areas (see Clause 1.4.15), but may also be applied to other patient locations, especially where Class B medical electrical equipment is used FIGURE J1 PATIENT ENVIRONMENT COPYRIGHT 71 AS/NZS 3003:1999 J3 EQUIPMENT USED OUTSIDE OPERATING THEATRES AND DEDICATED BODY-PROTECTED AREAS Other equipment which by virtue of its location and use may be classified as medical electrical equipment shall, when supplied by mains, be protected by a 10 mA RCD Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited J4 GENERAL In addition to the regulatory requirements for earthing, cardiac-protected electrical areas shall comply with the additional equipotential earthing system requirements set out in Paragraphs J5 to J11 J5 PROVISION OF EP SYSTEM One equipotential earthing system may serve more than one patient environment, but a patient environment shall not be served by more than one equipotential earthing system J6 FORM OF EP SYSTEM Each equipotential earthing system shall — (a) consist of one EP junction isolated from earth; (b) have insulated conductors between the bonding terminal(s) and EP junction; and (c) have a minimum size conductor of mm high-conductivity copper conductor Each equipotential earthing system shall — (i) have its EP junction clearly labelled and accessible; (ii) be connected to the earth bar of the switchboard supplying electricity to that area with an earth conductor of mm high-conductivity copper conductor; and (iii) have its earthing continuity conductor clearly labelled at that switchboard ‘EQUIPOTENTIAL BUS JUNCTION EARTH, DO NOT DISCONNECT’ Earthing and equipotential earthing conductors shall be of continuous construction, i.e the removal of a single fitting shall not break the continuity of the earthing or equipotential earthing conductor, or both, when serving several fittings J7 TOUCH VOLTAGE The touch voltage between medical electrical equipment and exposed conductive parts within the patient environment measured to the equipotential earthing junction shall not exceed 50 mV when the installation is operating under normal conditions J8 PIPELINE ISOLATORS Piped services (medical gas and suction) shall be fitted with electrical pipeline isolators when first entering EP areas J9 CONNECTION OF ITEMS TO THE EQUIPOTENTIAL EARTHING SYSTEM J9.1 Items to be connected to the equipotential earthing system (other than the EP junction) The following items within a protected electrical area shall have a direct electrical connection to the equipotential earthing system (but not necessarily directly to the EP junction): (a) The earth terminals of socket-outlets (b) EP terminals adjacent to socket outlets The electrical resistance between any of the points identified in Items (a) and (b) and the EP junction shall not exceed 100 milliohm (0.1 ohm) J9.2 Items to be connected to the EP junction The following items within a patient environment shall be connected to the EP junction: (a) The accessible conductive parts of permanently connected fittings and electrical appliances (including operating theatre and fixed examination lights) (b) Medical gas and suction pipes (c) Exposed conductive parts of the installation The electrical resistance between any of the points identified in Items (a), (b) and (c) and the EP junction shall not exceed 100 milliohm (0.1 ohm) COPYRIGHT AS/NZS 3003:1999 72 J10 CONDUITS Medical fittings and medical electrical appliances having an equipotential earthing terminal shall be connected to the equipotential earthing system by an equipment earthing conductor Equipment earthing conductors shall: (a) be of high-conductivity copper; (b) have a cross-section of not less than mm 2; (c) have insulation colouring of either green or a combination of green and yellow; and (d) have maximum length of m J11 EQUIPMENT EP TERMINALS Sufficient EP terminals shall be provided in each protected area to facilitate the earthing of electrical equipment Licensed to LUU MINH LUAN on 25 Feb 2002 Single user licence only Storage, distribution or use on network prohibited EP terminals shall be of a compatible type throughout protected electrical areas of the installation COPYRIGHT ... wired as body-protected electrical areas or as cardiac-protected electrical areas Requirements for mobile trolleys AS/ NZS 3200.1.0 and AS/ NZS 4510 supporting electrical equipment are given in Requirements... and operation 3000 Electrical installations — Buildings, structures and premises (known as the SAA Wiring Rules) COPYRIGHT AS/ NZS 3003:1999 AS 3011 3011.1 3011.2 Electrical installations — Secondary... cardiac-protected areas; COPYRIGHT AS/ NZS 3003:1999 (b) attention be given to the recommendations of AS/ NZS 2500 listing the electrical supply and equipment protective measures appropriate for