AS NZS 3003 1999 electrical installations

AS 3000, SAA Wiring Rules.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 en

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AS/NZS 3003:1999 Electrical installations - Patient treatment areas of hospitals and

medical and dental practices

Licensed to LUU MINH LUAN on 25 Feb 2002

AS/NZS 3003:1999

Electrical installations—Patient treatment areas of hospitals and medical and dental practices

This Joint Australian/New Zealand Standard was prepared by Joint TechnicalCommittee HT/21, Wiring of Medical Treatment Areas in Hospitals It wasapproved on behalf of the Council of Standards Australia on 23 November 1998and on behalf of the Council of Standards New Zealand on 7 December 1998 Itwas published on 5 February 1999.

The following interests are represented on Committee HT/21:

Association of Consulting Engineers, AustraliaAustralian Chamber of Commerce and IndustryAustralian Dental Association

Australian Federation for Medical and Biological EngineeringAustralian Nursing Federation

Australian Private Hospitals AssociationAustralian Society of AnaesthetistsBiomedical Engineering Advisory Group SACanterbury Area Health NZ

College of Biomedical Engineering Institution of Engineers AustraliaDepartment of Public Works and Services NSW

Electricity Supply Association of AustraliaHealth Department, WA

Institute of Hospital Engineering (Australia)Medical Industry Association of AustraliaMinistry of Commerce, NZ

NSW Health DepartmentNational Electrical Contractors Association of AustraliaRoyal 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 theissue of amendments or new editions as necessary It is important therefore thatStandards users ensure that they are in possession of the latest edition, and anyamendments thereto

Full details of all Joint Standards and related publications will be found in the StandardsAustralia and Standards New Zealand Catalogue of Publications; this information issupplemented each month by the magazines ‘The Australian Standard’ and ‘StandardsNew Zealand’, which subscribing members receive, and which give details of newpublications, new editions and amendments, and of withdrawn Standards

Suggestions for improvements to Joint Standards, addressed to the head office of eitherStandards Australia or Standards New Zealand, are welcomed Notification of anyinaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should bemade without delay in order that the matter may be investigated and appropriate actiontaken

AS/NZS 3003:1999

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

1 The Crescent,Homebush NSW 2140 AustraliaStandards New Zealand

Level 10, Radio New Zealand House,

155 The Terrace,

AS 3000, SAA Wiring Rules.

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 ofprocedures 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 canthen be identified and wired as body-protected electrical areas or cardiac-protectedelectrical areas to provide the necessary level of electrical shock protection in the mainssupply wiring and, where appropriate, earthing systems

The earliest consultation between hospital management and the electrical design engineers

is recommended, to jointly evaluate the elected procedures likely to be undertaken, inorder to determine which areas of the hospital or medical or dental practice should bewired 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 isstrongly recommended that hospital managements carefully evaluate the proceduresundertaken within existing installations, and that they take steps to implement theappropriate electrical safety requirements specified herein for areas that are used forcardiac-type procedures or for procedures involving the regular use of medical electricalequipment

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 residualcurrent device or an isolated electrical supply

(d) Introduction of requirements for earth leakage protection for socket-outlets whichare outside the defined protected electrical areas but which would normally beexpected 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 isolatedelectrical supplies and their relocation in AS/NZS 4510

(i) The revised presentation information on testing and commissioning in a morelogical sequence for the convenience of persons carrying out the tests

(j) Alterations to the requirements relating to equipotential earthing systems incardiac-protected areas

The terms ‘normative’ and ‘informative’ have been used in this Standard to define theapplication of the appendix to which they apply A ‘normative’ appendix is an integralpart of a Standard, whereas an ‘informative’ appendix is only for information andguidance.

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Page

SECTION 1 SCOPE AND GENERAL

1.1 SCOPE 6

1.2 APPLICATION 7

1.3 REFERENCED DOCUMENTS 7

1.4 DEFINITIONS 8

1.5 METHOD OF MARKING 11

SECTION 2 GUIDANCE 2.1 INTRODUCTION 13

2.2 AREA SELECTION 13

2.3 CLASSIFICATION SELECTION 14

SECTION 3 BODY-PROTECTED ELECTRICAL AREAS 3.l GENERAL 15

3.2 SUPPLY WIRING 15

3.3 EARTHING 16

3.4 ACCESS TO LEAKAGE PROTECTIVE DEVICES AND LINE ISOLATION MONITORS 16

3.5 SOCKET-OUTLETS 16

3.6 RESIDUAL CURRENT DEVICES (RCDs) 17

3.7 LOW VOLTAGE ISOLATED SUPPLIES 18

3.8 ISOLATING SWITCHES 19

3.9 MARKING 19

3.10 COMMISSIONING 19

SECTION 4 CARDIAC-PROTECTED ELECTRICAL AREAS 4.l GENERAL 20

4.2 SUPPLY WIRING 20

4.3 EARTHING 22

4.4 ACCESS TO LEAKAGE PROTECTIVE DEVICES AND LINE ISOLATION MONITORS 29

4.5 SOCKET-OUTLETS 29

4.6 RESIDUAL CURRENT DEVICES (RCDs) 30

4.7 ISOLATED SUPPLIES (OTHER THAN ELV) 31

4.8 ISOLATING SWITCHES 32

4.9 MARKING 32

4.10 COMMISSIONING 32

APPENDICES A RATIONALE FOR THE REQUIREMENTS OF THIS STANDARD 33

B PLANNING OF AREAS 38

C MARKING OF BODY-PROTECTED ELECTRICAL AREAS AND CARDIAC-PROTECTED ELECTRICAL AREAS 42

D COMMISSIONING TESTS FOR BODY-PROTECTED ELECTRICAL AREAS AND CARDIAC-PROTECTED ELECTRICAL AREAS 43

E MEASURES FOR AVOIDING INTERFERENCE FROM MAGNETIC FIELDS 60

F METHOD FOR MEASURING MAGNETIC FIELDS 61

G INSTRUMENT FOR MEASURING POTENTIAL DIFFERENCES IN ANINSTALLATION 63

H EARTHING OF PERMANENTLY WIRED ELECTRICAL EQUIPMENT IN

EP AREAS 65

I CALCULATIONS FOR EQUIPOTENTIAL EARTHING SYSTEMS 68

J ADDITIONAL REQUIREMENTS FOR APPLICATION IN NEW ZEALAND 70

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 1 S C O P E A N D G E N E R A L

patient treatment areas of hospitals and other medical and dental practices in which theadministration 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 duringbody type procedures; or

(c) use multiple pieces of medical equipment with Type BF applied parts during bodytype 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 patienttreatment areas in hospitals and other medical and dental practices in New Zealand (seeAppendix J)

Patient treatment areas other than body-protected electrical areas or cardiac-protectedelectrical areas are not covered by this Standard, but are covered by the relevantrequirements of AS 3000

NOTES:

1 Attention is drawn to AS/NZS 2500, which outlines the method of determining theclassification of various procedures and recommends routine operational and maintenanceprocedures to ensure the safe use and interconnection of medical electrical equipment ThatStandard also explains how several procedures commonly carried out in a general ward areaare classified under certain conditions as cardiac-type procedures warranting extremecaution

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 thenappropriate cardiac-protected electrical areas need to be provided

4 The number and disposition of cardiac-protected electrical areas that should be providedwill be dependent on the types of procedures that the hospital or medical practice haselected to undertake

5 Hospitals and medical practices that might not propose to undertake cardiac-type proceduresmay, in the case of emergency, temporarily upgrade an area in accordance with therecommendations and limitations identified in AS/NZS 2500, to provide temporary electricalprotection

6 The increasing use and application of medical electrical equipment in medicine and therange of electrical protection provided by such equipment, ranging from no isolation to fullisolation, makes it difficult to determine which patient treatment areas will requirecardiac-type or body-type electrical protective measures in the electrical installation It istherefore recommended that, during any electrical installation in patient treatment areas—(a) close attention be given to the relevant requirements herein (earthing, subcircuit layoutand other factors) that will facilitate conversion of areas to either body-protected orcardiac-protected areas;

(b) attention be given to the recommendations of AS/NZS 2500 listing the electrical supplyand equipment protective measures appropriate for particular medical procedures; and(c) consideration be given to residual current device (RCD) protection of other patienttreatment areas where equipment to be used will be likely to be subjected to spilling orsplashing of liquids Areas such as dialysis rooms should always be wired as body-protected electrical areas because of the presence and likely spillage of copiousamounts of liquid.

7 It is important for hospital managements and the electrical design engineers to evaluatejointly the elected procedures likely to be undertaken and to determine which areas of theinstallation should be wired as body-protected electrical areas or as cardiac-protectedelectrical areas

8 Requirements for mobile trolleys supporting electrical equipment are given inAS/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

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 therequirements of this Standard The requirements include the following:

(a) 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

(b) 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 orcarried out after the date of publication of this Standard However, hospital managementshould carefully evaluate the procedures electively undertaken within existing hospitalsand take steps to implement the requirements specified herein for the appropriate class ofarea

Standard:

AS

1125 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 Emergency evacuation lighting for buildings

2293.1 Part 1: System design, installation and operation

3000 Electrical installations — Buildings, structures and premises (known as the

SAA Wiring Rules)

3011 Electrical installations — Secondary batteries installed in buildings

3011.1 Part 1: Vented cells

3011.2 Part 2: Sealed cells

3111 Approval and test specification — Miniature overcurrent circuit-breakers

3147 Approval and test specification — Electric cables — Thermoplastic insulated —

For working voltages up to and including 0.6/1 kV

3190 Approval and test specification — Residual current devices (current-operated

earth-leakage devices)AS/NZS

2500 Guide to the safe use of electricity in patient care

3008 Electrical installations — Selection of cables

3008.1.1 Part 1.1: Cables for alternating voltages up to and including 0.6/1 kV —

Typical Australian installation conditions3008.1.2 Part 1.2: Cables for alternating voltages up to and including 0.6/1 kV —

Typical New Zealand installation conditions

3009 Electrical installations — Emergency power supplies in hospitals

3100 Approval and test specification — General requirements for electrical

equipment

3108 Approval and test specification — Particular requirements for isolating

transformers and safety isolating transformers

3112 Approval and test specification — Plugs and socket-outlets

3116 Approval and test specification — Electric cables—Elastomer insulated — For

working voltages up to and including 0.6/1 kV

3200 Medical electrical equipment

3200.1.0 Part 1.0: General requirements for safety — Parent Standard

4510 Isolated electrical supply systems for medical use

VDE

0107 Electrical installations in hospitals and locations for medical use outside

hospitals (English language version issued by the British Standards Institution)

those below apply

Type BF or Type B in accordance with AS 3200.1.0

electrical contractor or electrician or other person appointed or selected by the person incharge of the premises to perform certain duties associated with the electrical installation

on the premises

protection against electric shock following contact with live parts of accessories orequipment connected to the mains supply (‘macro shock’)

medical electrical equipment so that the impedance of the skin is reduced by electrodepaste or by the entrance of conducting fluids, metal needles and saline-filled catheters, butwhere direct contact with the heart is not possible, e.g in extra-thoracic procedures

1.4.5 Cardiac-protected electrical area — a protected electrical area intended to provide

within the heart of a patient or is likely to come into contact with the heart, suchconductor being accessible outside the patient’s body In this context, an electricalconductor includes electrical wires such as cardiac pacing electrodes and intracardiac ECGelectrodes, or insulated tubes filled with conducting fluids

electrical areas providing a means of connection to the equipotential earthing system

the jointed test fingers, defined in AS 3200.1.0, other than the following:

(a) Live parts

(b) Parts separated from live parts by double insulation or reinforced insulation

(c) Metal nameplates, screw-heads, covers or plates —

(i) which are supported on or attached or connected to substantial non-conductivematerial in such a manner that they cannot become alive in the event of failure

of insulation of live parts; and(ii) whose means of fixing cannot come into contact with any internal metal, otherthan earthed metal or parts referred to in Item (d), or be exposed to arcingcontact with live parts

NOTE: ‘Failure of insulation’ in this context is taken to include accidental bridging of aninsulating gap by metal or partially conducting material such as carbon dust or moisture, aswell as breakdown in the conventional sense

(d) Parts that are separated from live parts by other metal parts which are themselvesearthed or have double insulation or reinforced insulation

(e) Parts within an enclosure, the cover of which requires the use of a tool for itsremoval

NOTE: A key is not considered to be a tool except where special circumstances prevail, e.g.the use of the key is restricted to technical service personnel having an appropriate level ofelectrotechnical training

(f) Parts within equipment, the configuration and mass of which are such that the partsare not accessible during normal use and movement of the equipment

Non-metallic material which is conductive to a degree that may contribute to a hazardouscondition arising is deemed to be exposed metal, subject to the limitations of Items (a) to(f)

leakage protective device

accordance with AS 3190 or an isolating transformer device in accordance with AS 4510

the prospective hazard current and to actuate an alarm when this current exceeds a presetlevel

1.4.12 Medical electrical equipment — electrical equipment provided with not more

than one connection to a particular supply mains and intended to diagnose, treat ormonitor the patient under medical supervision; and which makes physical or electricalcontact with the patient, or transfers energy to or from the patient, or detects such energytransfer to or from the patient

NOTES:

1 Examples of diagnostic medical electrical equipment are —(a) electrocardiographs, electro-encephalographs, electromyographs and multichannelpolygraphs; and

(b) X-ray, ultrasonic, gamma ray and infrared organ-imaging equipment

2 Examples of therapeutic medical electrical equipment are —(a) electrosurgical equipment;

(b) patient heating and cooling devices;

(c) dialysis machines;

(d) electrically powered or controlled respirators;

(e) electrical injections and pumps, to infuse fluids into the patient; and(f) electrodental equipment

current of an isolated supply and to actuate an alarm when the current exceeds the rating

of the isolating transformer

cardiac-protected electrical area in which the potential difference between earthingconnections of particular equipment has been minimized

Each EP area extends to the distances from the intended location of the patient, as shown

in Figure 1.1, in which intentional or unintentional contact between patient and equipment

or some other person touching the equipment can occur

Where the perimeters of adjacent EP areas overlap the combined area is deemed to be one

EP area However, where a bed is placed adjacent to the wall, the EP area does not extendthrough the wall

DIMENSIONS IN MILLIMETRES

FIGURE 1.1 PATIENT EQUIPOTENTIAL AREA (EP AREA)

1.4.16 Patient equipotential junction (EP junction) — the junction of the EP earthing

system and the return earth

for a patient, whether or not occupied by the patient

Where the location of a patient undergoing a medical electrical procedure is likely to varyfor different occasions, e.g in some operating theatres, the patient location extends to theentire room This includes locations for incubators or cribs in delivery suites

supply, between one of the active conductors and earth if the other active conductor weresolidly bonded to earth

NOTE: Although this current does not flow until a line-to-earth fault occurs, a line can bedescribed as having a prospective hazard current of a particular value because, as a result of thecumulative effect of the imperfections in the line isolation, current will flow as soon as aline-to-earth fault occurs

with the requirements of this Standard

A protected electrical area may contain one or more patient locations if a body-protectedarea, or one or more EP areas if cardiac protected

The boundaries of the protected electrical area extend to the walls enclosing the patientlocations or EP areas or, if such walls are incomplete (e.g entryway without a door), tothe boundary formed if such walls or projections were extended The boundary extends to

a height of 2.3 m from the floor on any wall deemed to be in or a boundary of theprotected electrical area The boundary includes the front facade of any nurses’ stationlocated in the space but does not extend through or behind this station

Where all the patient locations enclosed by the boundary described above are not beingwired according to this Standard the protected electrical area shall, as a minimum, extend

to the distances from the intended patient locations as shown in Figure 1.2 The areadescribed by the locus of the line need not extend through walls

If an operating theatre, a delivery suite or a day procedure room is to be a protectedelectrical area, the whole room is deemed a protected electrical area in accordance withthis Standard

installation earth at the main earthing conductor at the main switchboard, or to thesubmain earthing conductor at the distribution board, as appropriate

isolated from earth by means of an isolating transformer

made either on the equipment itself or on a plate securely fixed to the equipment

Adhesive metallic labels shall not be fixed in locations where, if they become detached,they may readily touch live parts or bridge insulation

Plates incorporating a durable surface finish, including those with particulars printedphotographically in conjunction with anodizing, shall be regarded as indelible

Where marking is by adhesive non-metallic labels, surface transfers, painting, screening printing with etching dyes or similar means, the marking shall be sufficientlydurable for its purpose and located where it will not be subjected to conditions that maylead to its deterioration, having regard to the quality of marking, the surface to which it isapplied, and service conditions such as temperature, moisture, abrasion and handling

silk-DIMENSIONS IN MILLIMETRES

FIGURE 1.2 BOUNDARY OF PROTECTED ELECTRICAL AREA

S E C T I O N 2 G U I D A N C E

installations in patient treatment areas The selection of which particular patient treatmentareas in hospitals and other medical and dental practices are to be wired according to thisStandard requires careful consideration by the appropriate design, engineering and clinicalstaff Once an area has been designated as requiring one of the specialized wiring systemsset out in this Standard the classification chosen for each area should be based entirely onconsideration of the types of medical procedures to be done in the particular area

NOTE: Appendix B gives detailed guidance on planning of areas with characteristics of bothRCD and transformer isolated supply systems

electrical equipment is routinely used for body-type procedures (see Clause 1.4.4) asdiscussed in AS/NZS 2500 need be wired according to this Standard

Most modern electro-medical equipment used for doing body-type procedures, i.e.equipment having a type BF or CF applied part, does not need any special wiring for theprocedure to be done safely from an equipment or installation perspective, if a singlepiece of equipment is being used In all procedures safe practice is always necessary.Recommendations for safe practice are detailed in AS/NZS 2500

For the purposes of this Section ‘applied parts’ refers only to —

(a) a transducer which makes contact with the patient;

(b) an electrode which makes contact with the patient;

(c) a part which enters the patient; or

(d) a part which contains liquid which in turn enters the patient

Areas where the equipment used does not offer any specific patient protection fromelectrical hazards, i.e equipment having a B type applied part as described in Items (a) to(d), need to be wired according to this Standard In modern medical practice examples ofthis type of equipment are not common; however, some equipment is manufactured withType B applied parts, e.g dialysis machines and arthroscopic shavers Other examplesmight occur in some specialized medical practices

Other areas that are commonly wired according to this Standard are operating theatres,intensive and coronary care units, cardiac catherization laboratories, and accident andemergency rooms

All other patient areas of a facility, i.e those where no electro-medical procedures areroutinely done using a type BF or CF applied part, have no specific need to be wiredaccording to this Standard

This Standard allows areas wired as body-protected or cardiac-protected to occupy a part

of a defined space or room alongside areas wired according to AS 3000 Minimumclearance distances between protected and unprotected outlets have been specified toreduce the possibility of confusion between the power outlets of the two types of areas

It is strongly recommended that clinical staff responsible for the treatment of patients ineach area of the facility should be consulted when decisions relating to the wiringrequirements of each area are taken

2.3 CLASSIFICATION SELECTION Nearly all areas of hospitals and other medicaland dental practices wired according to this Standard will only need to meet therequirements given for a body-protected electrical area (see Section 3).

Cardiac-protected electrical areas (see Section 4) are required only where there is directelectrical connection with the patient’s heart These types of procedures normally onlyoccur in large acute-care hospitals and are nearly always confined to cardiaccatheterization laboratories, special open heart theatres and high-level intensive care units.Some other areas will also need to meet the requirements, if cardiac-type procedures arecarried out

AS/NZS 2500 provides recommendations on establishing temporary cardiac-protectedelectrical areas for emergency or short-term use Only those areas that undertake routineapplication of direct electrical connection to a patient’s heart need be wired in accordancewith the cardiac-protected electrical area requirements

The additional requirements for cardiac-protected electrical areas, particularly thoseassociated with the equipotential bonding, result in higher installation costs, especiallywhere existing areas are being upgraded Many examples exist of patient treatment areasthat, needlessly, have been wired in accordance with these requirements

S E C T I O N 3 B O D Y - P R O T E C T E D

E L E C T R I C A L A R E A S

specified in this Section

NOTES:

1 Body-protected electrical areas are defined in Clause 1.4.3 and are those medical treatmentareas, other than cardiac-protected electrical areas, which are wired to provide protectionadditional to that provided by wiring to AS 3000, for the routine and regular performance ofbody-type procedures using medical electrical equipment having Type B (unprotected)applied parts

2 Rooms such as ECG, EMG, EEG and physiotherapy rooms should be wired asbody-protected electrical areas unless the management of the hospital or medical practicehas decided to use therein equipment having only Type CF or Type BF patient-circuits

3 Areas such as dialysis rooms should always be wired as body-protected electrical areasbecause of the presence and likely spillage of copious amounts of liquid

4 AS 1169 contains requirements for antistatic flooring for areas in which flammableanaesthetics are used

LPDs shall be provided to the following —

(a) All socket-outlets, except those identified in Items (i) and (ii), within thebody-protected electrical area, including those on permanently wired equipment

(b) All socket-outlets, except those identified in Items (i) and (ii), located outside thedefined protected electrical area but which would normally be used to power either —(i) equipment located within the area; or

(ii) equipment brought into the area while still connected to the outlet (e.g a

mobile X-ray machine)

(c) Permanently wired medical electrical equipment having a Type B applied partconsisting of patient circuits having —

(i) a transducer which makes contact with the patient;

(ii) an electrode which makes contact with the patient;

(iii) a part which enters the patient; or(iv) a part which contains a liquid which in turn enters the patient

Protection by LPDs is not required for —

(i) socket-outlets installed for the connection of clocks; and

(ii) ceiling-mounted socket-outlets (and socket-outlets mounted on the wall at the height

of more than 2.3 m) specifically intended for permanently mounted, plug-inequipment such as patient monitors, TV receivers and airconditioners

All unprotected socket-outlets located in the vicinity of the protected electrical area shall

be at least 3 m, line-of-sight, from the nearest LPD-protected outlet in the protected area.All other supply wiring within the body-protected electrical area shall be protected inaccordance with AS 3000

1 Characteristics of both RCD-protected and transformer isolated supply systems are detailed

in Appendix B together with pertinent features to be considered when the type of supplysystem to be incorporated is chosen

2 Where ‘mixed systems’ (i.e RCD-protected points and transformer isolated points) areinstalled, attention should be given to the marking requirements of Clause 3.5.2 and to theneed to clearly indicate the type of supply available at any particular point In addition,rigorous staff education programs should be undertaken in accordance with therecommendations of AS/NZS 2500 Where only one type of protection system isincorporated, i.e RCD or isolated supply, understanding of the system by the user is lessdifficult

emergency supplies, shall not be earth referenced

NOTE: AS 3011.1 and AS 3011.2 contain requirements for secondary batteries installed inbuildings

AS 3000 and shall not have exposed live parts

AS 3000

shall be located within the body-protected area:

(a) Test and reset facilities for RCDs

(b) Overload monitors for isolating transformers

Line isolation monitors shall be accessible without the use of a key and shall be locatedeither within the body-protected area or within the nurses’ station

The requirements of this Clause need not apply to LPDs provided for floor cleaningpurposes in accordance with Clause 3.5.1.2

likely location of equipment and all socket-outlets shall be positioned for easy access

NOTE: Not less than two socket-outlets should be provided at each patient location in abody-protected electrical area A larger number of socket-outlets will be necessary in somepatient locations in body-protected electrical areas, to avoid the use of extension cords orsocket-outlet adaptors

body-protected areas they shall be —

(a) protected by a LPD; and

(b) marked, in accordance with Clause 1.5, with the words ‘FLOOR CLEANINGPURPOSES ONLY’

The LPD protecting this circuit shall not be used to protect socket-outlets intended for usewith medical electrical equipment

The requirements of Clause 3.4 need not apply to this LPD

NOTE: This LPD may be used to protect other similar outlets for other body-protected areas

3.5.2 Marking and identification of socket-outlets Each socket-outlet or group ofsocket-outlets which are remote from the LPD controlling them shall be identified(numbered or lettered) in a manner which identifies the approprite LIM and overloadmonitor or the appropriate RCD Each socket-outlet or group of socket-outlets suppliedfrom RCD-protected circuits shall be fitted with an amber, yellow or orange luminousindicator to indicate that the supply is available In addition, socket-outlets shall bemarked, in accordance with Clause 1.5 —

(a) to indicate when the socket-outlet switch is ‘ON’, e.g by a red-coloured luminousindicator or red marking; and

(b) with the words ‘RCD-PROTECTED’ to indicate that the socket-outlet is protected

by an RCD

Each socket-outlet or group of socket-outlets supplied from an isolating transformer shall

be marked, in accordance with Clause 1.5, with the words ‘ISOLATINGTRANSFORMER PROTECTED’

In addition, socket-outlets shall be suitably and permanently marked to indicate when thesocket-outlet switch is ‘ON’, e.g by a red-coloured luminous indicator or red marking

The requirements for marking and identification need not apply to socket-outlets providedfor cleaning purposes in accordance with Clause 3.5.1.2

NOTE: Adjacent socket-outlets constitute a group only if they are all contained within onecontiguous enclosure or panel

a.c supply at nominal mains voltage

Socket-outlets shall be switched in all active conductors

NOTE: All isolated supply conductors are active conductors

comply with AS 3190 and shall have a rated residual current not exceeding 10 mA

NOTE: The RCD may be combined with the overcurrent protective device required by AS 3000

NOTE: This requirement is the same as that for RCDs in cardiac-protected electrical areas Itinvolves the installation of an RCD which switches all live conductors, gives protection wherethe potential of the neutral conductor may be considerably higher than earth potential, and alsofacilitates conversion to a cardiac-protected electrical area if this were subsequently required

electrical area should be discriminatory in its operation, i.e an earth fault in any onesubcircuit should not cause interruption of the supply to other subcircuits

not more than 12 points, i.e socket-outlets or permanently wired equipment, orcombinations thereof Attention is drawn, however, to the desirability in certain areas forfewer points to be controlled by any one RCD

NOTES:

1 More than one patient location may be controlled by one RCD

2 In the planning of the number of points to be controlled by an RCD, consideration should begiven to the type and number of equipment to be used and the need to minimize interruption

of supply to any patient location

3.6.5 Indication If the location of any RCD is remote from the socket-outlets that itsupplies, the RCD shall be provided with a luminous indicator to show when power isavailable to the socket-outlets.

accordance with Clause 1.5 to indicate the points that it controls

permanently wired equipment, access to the load circuit for testing the operation of theRCD shall be provided

This facility shall be legibly and indelibly marked ‘TEST ONLY’ and shall be accessible.The test facility shall be marked, in accordance with Clause 1.5, to identify the RCD that

it tests

A socket-outlet may be used, where access to the socket-outlet is by means of a tool

comply with the requirements of AS/NZS 4510

The isolated supply shall comprise the following:

(a) Isolating transformer

(b) Overload monitor, except where exempted by Clause 3.7.3

(c) Line isolation monitor

For New Zealand, approved resistance-type monitoring systems shall apply Suitableresistance-type monitoring systems include systems that comply with VDE 0107

NOTE: The IEC is developing a Standard for resistance-type monitoring systems

with the requirements of AS 3000 and the manufacturer’s instructions, in a space orenclosure so that in normal operation at the rated load, the temperature of the space orenclosure does not exceed the maximum ambient temperature marked on the isolatingtransformer The isolating transformer manufacturer’s advice should be sought oninstalling an isolating transformer in a space or enclosure so that the isolatingtransformer’s maximum temperature is not exceeded

Where an isolating transformer supplies two or more patient locations, duplicate alarmsand controls shall be provided where patient locations are not in direct visual contact

monitor to monitor the isolating transformer current The alarm point rating of theoverload monitor shall be marked on the monitor, in accordance with Clause 1.5, tofacilitate testing

This Clause applies to all isolating transformers except those which, because of thecharacteristics of the load, are not likely to carry overload current, and which supply onlypermanently wired equipment

NOTE: The overload monitor may be combined with the line isolation monitor required byClause 3.7.4

isolation monitor (LIM) to monitor the prospective hazard current

It shall not be possible to deactivate the LIM without the use of a tool

NOTE: The LIM may be combined with the overload monitor required by Clause 3.7.3

Each LIM shall be identified (numbered or lettered) in a permanent manner whichidentifies the points, i.e socket-outlets or permanently connected equipment, with which it

is associated

3.7.5 Overcurrent circuit-breaker The primary circuit of every isolating transformershall be protected by a miniature overcurrent circuit-breaker complying with AS 3111.The rating of the overcurrent circuit-breaker shall not exceed the primary current rating ofthe transformer.

NOTE: This miniature overcurrent circuit-breaker may be the same device as the overloadprotective device required by AS 3000

supply, LIM and circuit wiring, but not including other equipment intended for connection

to the circuit, shall not exceed 2 mA, when measured in accordance with AS/NZS 4510

NOTES:

1 Metallic conduit provides some protection against electrical interference and may be used,provided that it does not cause the prospective hazard current to exceed that permitted bythis Clause

2 The length of isolated supply circuits should be as short as practicable in order to minimizethe total prospective hazard current

to a final subcircuit supplied from an isolated supply shall be determined in accordancewith AS 3000

NOTE: Separate supplies may need to be provided to each patient location in order to—

(a) reduce the size of the transformer and the magnitude of the prospective hazard current;

(b) limit the complexity of the installation; and(c) obviate any duplication of alarms and controls

only to permanently wired equipment, access for testing the operation of the LIM shall beprovided This facility shall be marked, in accordance with Clause 1.5, ‘TEST ONLY’ andshall be accessible The test facility shall be marked, in accordance with Clause 1.5, toidentify the LIM that it tests

A socket-outlet may be used where access to the socket-outlet is by means of a tool

a leakage-protected circuit shall be provided with an individual isolating switch that shalloperate in all live conductors

shall be affixed in body-protected electrical areas, at a height approximately 2 m abovefloor level, to indicate the status of the area

NOTE: Means for the recording thereon of the most recent test date and the authorized person’ssignature are also recommended

relevant testing and inspections listed in Appendix D, prior to commissioning of the area

S E C T I O N 4 C A R D I A C - P R O T E C T E D

E L E C T R I C A L A R E A S

specified in this Section

NOTES:

1 Cardiac-protected electrical areas are defined in Clause 1.4.5 They are the only treatmentareas which are wired to provide protection and equipotential measures for undertakingcardiac-type procedures

2 During the design and installation phases consideration should be given to measures whichminimize interference from magnetic fields This interference may cause a dangeroussituation for the patient or may cause incorrect measurements Guidance on measures foravoiding interference from magnetic fields is given in Appendix E A method for measuringmagnetic fields is given in Appendix F Other methods and instruments may be used

3 If a hospital has elected to undertake cardiac-type procedures then appropriatecardiac-protected electrical areas will be provided

4 The cardiac-protected electrical areas which should be provided will depend on the types ofprocedures which the hospital has elected to undertake Some areas, such as cardiaccatheterization laboratories and operating theatres where thoracotomies are to be undertaken,will always be cardiac-protected electrical areas

Other areas, including operating theatres in the same suite, need not be wired ascardiac-protected electrical areas, unless it is intended to carry out cardiac-type procedurestherein

5 Hospitals which may not propose to undertake cardiac-type procedures may, in the case ofemergency, temporarily upgrade an area in accordance with the recommendations andlimitations identified in AS/NZS 2500, to provide temporary protection

6 AS 1169 contains requirements for antistatic flooring for areas in which flammableanaesthetics are used

LPDs shall be provided to the following:

(a) All socket-outlets within the cardiac-protected electrical area, including those onpermanently wired equipment

(b) All socket-outlets located outside the defined protected electrical area but whichwould normally be used to power either —

(i) equipment located within the area; or(ii) equipment brought into the area while still connected to the outlet (e.g a

mobile X-ray machine)

(c) Permanently wired medical electrical equipment having a Type B applied partconsisting of patient circuits having —

(i) a transducer which makes contact with the patient;

(ii) an electrode which makes contact with the patient;

(iii) a part which enters the patient; or(iv) a part which contains a liquid which in turn enters the patient

Protection by LPDs is not required for the following:

(i) Fixed X-ray installations which comply with the safety requirements of theappropriate part of AS 3200 unless they incorporate a Type B applied partconsisting of —

(A) a transducer which makes contact with the patient;

(B) an electrode which makes contact with the patient;

(C) a part which enters the patient; or(D) a part which contains liquid which in turn enters the patient

(ii) Socket-outlets installed for the connection of clocks

(iii) Ceiling-mounted socket-outlets (and socket-outlets mounted on the wall at theheight of more than 2.3 m) specifically intended for permanently mounted, plug-inequipment such as patient monitors, TV receivers and airconditioners

All unprotected socket-outlets located in the vicinity of the protected electrical area shall

be at least 3 m, line-of-sight, from the nearest LPD-protected outlet in the protected area.All other supply wiring within the cardiac-protected electrical area shall be protected inaccordance with AS 3000

NOTES:

1 Characteristics of both RCD-protected and transformer-isolated supply systems are detailed

in Appendix B together with pertinent features to be considered when the type of supplysystem to be incorporated is chosen

2 Where ‘mixed systems’ (i.e RCD-protected points and transformer isolated points) areinstalled, attention should be given to the marking requirements of Clause 3.5.2 and to theneed to indicate clearly the type of supply available at any particular point In addition,rigorous staff education programs should be undertaken in accordance with therecommendations of AS/NZS 2500 Where only one type of protection system isincorporated, i.e RCD or isolated supply, understanding of the system by the user is lessdifficult

3 Consideration should be given to the protection of other electrical equipment by LPDs asthe equipotential earthing system requirements of LPD protected circuits may be lessonerous than those for unprotected circuits

4 A summary of the protection to be provided to wiring in a cardiac-protected area is shown

in Figure 4.1

voltage d.c emergency supplies, shall not be earth referenced

protected by an RCD complying with Clause 4.6

Where an ELV supply is not earth referenced and is reticulated to more than one outlet it shall be monitored by a LIM

socket-It shall not be possible to deactivitate the LIM without the use of a tool

NOTE: The LIM may be combined with the overload monitor required by Clause 4.7.3

Each LIM shall be identified (numbered or lettered) in a permanent manner whichidentifies the points, i.e socket-outlets or permanently wired equipment, with which it isassociated

Transformers associated with ELV supplies shall comply with AS/NZS 3108 or the supplyshall comply with Paragraph H3, Appendix H

ELV supplies shall not have exposed live parts

4.3 EARTHING

AS 3000, and with the variations given in Clauses 4.3.2 to 4.3.4.5 Appendix J gives analternative method applicable to New Zealand for compliance with Clause 4.3

The minimum size of any equipotential earthing system conductor shall be not less thanthat required by AS 3000

3 The equipotential earthing system conductors required by this Standard are intended to limitthe potential difference between earthed points in a cardiac protected area to 100 mV andare additional to equipotential bonding conductors required by AS 3000

only one equipotential earthing system

NOTE: One equipotential earthing system may serve more than one EP area

(a) An insulated system shall be used for earthing only protected items set out inClause 4.3.2.4 This system shall achieve the resistance values specified inClause 4.3.2.4 and shall comply with Item (c) The earthing of items detailed inClause 4.3.2.5 shall be carried out as specified in that Clause

(b) An insulated earthing system shall be used for earthing all the items set out inClauses 4.3.2.4 and 4.3.2.5 This system shall have a cross-sectional area such thatthe resistance between any item connected to the system and the EP junction shallnot exceed 0.01 ohms This system shall comply with Item (c)

(c) An equipotential earthing system shall be provided with only an EP junction (seeClause 4.3.2.7) All supply earthing conductors shall first terminate at the EPjunction All equipment protective earthing conductors shall terminate at the EPjunction

NOTES:

1 The equipotential earthing system may be any shape or form of conductor

2 The configuration of the equipotential earthing system is not a mandatory requirement ofthis Standard The equipotential earthing system should be located for convenience of access(particularly access for testing to the EP junction) and so that any branches thereof can bekept as short as practicable

3 The equipotential earthing system may describe any practicable route provided that itcomplies with the other requirements of this Section

4 Consideration should be given to the cross-sectional area of the return earth and the location

of the EP junction in areas in which fixed equipment (e.g X-ray equipment) is to beinstalled which may require larger current-carrying capacity conductors, to comply with —(i) the requirement of Item (b) that an equipotential earthing system shall be providedwith only one EP junction and one return earth conductor;

(ii) the requirements of Clause 4.3.2.3 regarding the minimum cross-sectional area of theequipotential earthing system; and

(iii) the requirements of AS 3000 regarding the relationship between the cross-sectionalarea of supply conductors and the protective earthing conductor

4.3.2.3 Size The minimum cross-sectional area of the equipotential earthing system shall

be in accordance with AS 3000

NOTES:

1 Figures 4.2 and 4.3 show examples of typical equipotential earthing connections in an EParea

2 Details on calculations for equipotential earthing systems are given in Appendix I

NOTE: Protected patient circuits will be labelled on the equipment as Class A, Class B, Type CF or Type BF Alternatively, protected patient circuits will be identified by ‘heart-in-square’ or ‘body-in-square’ labels For Figure 4.1 ‘patient circuit’ means a patient circuit having a connection to the patient according to Clause 4.2.1(c).

FIGURE 4.1 PROTECTION OF WIRING IN CARDIAC

4.3.2.4 Items to be connected to the equipotential earthing system (other than to EP junction) The following items within a cardiac-protected electrical area shall beconnected to the equipotential earthing system so that the resistance between any two ofthe points does not exceed 0.1 Ω:

(a) The earthing terminal of socket-outlets

(b) EP terminals

(c) The exposed metal of permanently wired electrical equipment which is—

(i) within the EP area; and(ii) protected by an LPD

(d) Metallic wiring enclosures which are —

(i) accessible within the EP area; and(ii) contain only wiring protected by an LPD

(e) The earthing terminal of luminaires which are —

(i) protected by an LPD; and(ii) not connected to structural steel

For the purpose of this Clause, an isolating transformer which complies withAS/NZS 3108 and which supplies only one item of equipment may be considered to be anLPD

For the purpose of this Clause, isolated structural elements, such as metal window frames

or door frames, that are inside the EP area need not be regarded as structural steel, exceptwhere these elements are connected to conducting parts of the main structure

3 Details on calculations for equipotential earthing systems are given in Appendix H

4 Information relating to equipotential earthing systems is given in Appendix I

shall be connected to the EP junction (see also Figure 4.2 and Appendix H):

(a) Exposed metal parts of permanently wired electrical equipment which is notprotected by an LPD

(b) Fixed electrical equipment with exposed metal parts which is connected to structuralsteel

(c) The mounting point of any conductive item which is accessible within the EP areaand is connected to structural steel (e.g roof-connected pendant mirror, fixedoperating theatre table)

(d) Metallic medical gas and suction pipes

(e) Reticulated metallic service pipes (e.g water, steam and drainage)

(f) Metallic wiring enclosures which contain circuits that are not protected by an LPD.The resistance between any one of Items (a) to (f) and the EP junction shall not exceedthe following:

(i) For points connected directly to the EP junction by a separate earthing conductor(see Figure 4.2) 0.1Ω

(ii) For points connected to earthing conductors which also serve to connect other

points (i.e Items (a), (b), (c), (d), (e), or (f)) to the EP junction(see Figure 4.3) 0.01Ω.This requirement need not apply to computer data connections

Non-conducting computer connection data plates should be used

For the purpose of this Clause, an isolating transformer which complies withAS/NZS 3108 and which supplies only one item of equipment may be considered to be anLPD

For the purpose of this Clause, isolated structural elements, such as metal window frames

or door frames, that are inside the EP area need not be regarded as structural steel, exceptwhere these elements are connected to conducting parts of the main structure

NOTES:

1 Services and structurally connected items within a cardiac-protected electrical area butoutside the EP area represent low impedance items which, even if raised to a potentialdifferent to that of the EP area, would not represent a source of current hazardous to thepatient

2 Figures 4.2 and 4.3 show examples of typical equipotential earthing connections in an EParea

3 Guidance on equipotential earthing systems and equipotential earthing of fixed equipment inthe EP area is given in Appendix H

4 Details on calculations for equipotential earthing systems are given in Appendix I

5 Where it is difficult to achieve the 0.01Ω resistance for electrical equipment, considerationshould be given to the use of LPDs

3 This 0.1 Ω connection directly to the EP junction is needed if the wall box is structurally connected.

FIGURE 4.2 EXAMPLE OF TYPICAL EQUIPOTENTIAL EARTHINGCONNECTIONS IN EP AREA OF CARDIAC-PROTECTED ELECTRICAL AREA

(System specified in Clause 4.3.2.2(a))

FIGURE 4.3 EXAMPLE OF TYPICAL EQUIPOTENTIAL EARTHING CONNECTIONS

IN EP AREA OF CARDIAC-PROTECTED ELECTRICAL AREA

(System specified in Clause 4.3.2.2(b)

4.3.2.6 Equipotential earthing connections All joints and connections to theequipotential earthing system and the EP junction shall comply with AS 3000, and withthe requirements of this Clause.

With the exception of the EP junction, all joints and connections shall be—

(a) fully insulated; and

(b) effected so that continuity of the equipotential earthing system does not depend onpressure of any single earthing screw

NOTE: This requirement may be satisfied by the use of at least two terminal screws for anytunnel connection or by the use of connecting boxes incorporating substantial separate studs(nut and bolt arrangements)

shall have only one EP junction The EP junction shall be clearly labelled and shall beconnected to the main or submain earthing conductor, which is associated with thecardiac-protected area distribution system, by a return earth A return earth may beconnected to more than one EP junction

Each EP junction shall be marked, in accordance with Clause 1.5, as either —

(a) ‘0.1 Ω EP EARTHING SYSTEM’; or

(b) ‘0.01 ΩEP EARTHING SYSTEM’

NOTE: The location of the EP junction is not a mandatory part of this Standard In the selection

of the location, attention should be given to—

(a) the need for access during commissioning and in-service testing;

(b) physical and electrical considerations that might favour the location of the EP junction atone of the items listed in Clause 4.3.2.5; and

(c) the relative locations of associated RCDs or isolating transformers

labelled ‘EP TEST POINT’ shall be provided in the EP area

with AS 3000

NOTE: In most installations, the cross-sectional area need not be as large as that of theequipotential earthing system

facilitate the earthing of electrical and non-electrical equipment

NOTE: Such earthing may be necessary for reasons of safety or performance of certain electrical equipment.

(a) Stud type terminals of 6 mm diameter provided with substantial captive fasteningnuts and washers and having suitable corrosion resistance and electrical conductivityproperties The washers shall be clamped by wing-nuts or large moulded grip-typenuts

(b) Suitable sockets or other devices of performance similar to a 6 mm stud typeterminal and having provision for locking the pin of a mating earth plug

EP terminals shall not require the use of a tool to make or break the connections

NOTE: All EP terminals in one installation should be compatible

the type of terminals employed and shall be as follows:

(a) Stud type terminals A minimum of one terminal per patient location or oneterminal per six socket-outlets, whichever is the greater, shall be provided; and eachsingle group of socket-outlets shall be provided with at least one EP terminal

(b) Socket type terminals A minimum of two terminals per patient location or oneterminal per three socket-outlets, whichever is the greater, shall be provided; andeach single group of socket-outlets shall be provided with at least one EP terminal.Terminals shall be located for convenience of connection and so that any bondingconductors to electrically operated equipment and metal objects within an EP area arekept as short as practicable.

structural metal, except where located at the EP junction

communication) having more than one EP area, EP terminals shall be marked, inaccordance with Clause 1.5, to identify the associated equipotential earthing system

Where EP terminals are grouped with socket-outlets marked in accordance withClause 4.5.2, a common identification is acceptable

equipment in EP areas shall be earthed according to Appendix H

shall be located within the cardiac-protected area:

(a) Test and reset facilities for RCDs

(b) Overload monitors for isolating transformers

Line isolation monitors shall be accessible without the use of a key and shall be locatedeither within the cardiac-protected area or within the nurses’ station

likely location of equipment and all socket-outlets shall be positioned for easy access

for cleaning purposes they shall be —

(a) protected by a LPD; and

(b) marked, in accordance with Clause 1.5, with the words ‘CLEANING PURPOSESONLY’

The earthing terminal of each socket-outlet provided for cleaning purposes shall beconnected to the nearest equipotential earthing system and the resistance shall satisfy theappropriate requirements

The LPD protecting this circuit should not be used to protect socket-outlets intended foruse with medical electrical equipment

NOTE: This LPD may be used to protect other similar outlets within the protected area

4.5.2 Marking and identification of socket-outlets Each socket-outlet or group ofsocket-outlets which are remote from the LPD controlling them shall be identified(numbered or lettered) in a manner which identifies the appropriate LIM and overloadmonitor or the appropriate RCD.

Each socket-outlet or group of socket-outlets supplied from RCD-protected circuits shall

be fitted with an amber, yellow or orange luminous indicator to indicate that the supply isavailable In addition, socket-outlets shall be marked, in accordance with Clause 1.5 —(a) to indicate when the socket-outlet switch is ‘ON’, e.g by a red-coloured luminousindicator or red marking; and

(b) with the words ‘RCD-PROTECTED’ to indicate that the socket-outlet is protected

by an RCD

Each socket-outlet or group of socket-outlets supplied from an isolating transformer shall

be marked, in accordance with Clause 1.5, with the words ‘ISOLATINGTRANSFORMER PROTECTED’

In addition, socket-outlets shall be suitably and permanently marked to indicate when thesocket-outlet switch is ‘ON’, e.g by a red-coloured luminous indicator or red marking.The requirements for marking and identification need not apply to socket-outlets providedfor cleaning purposes in accordance with Clause 4.5.1.2

In any room (or adjacent rooms in free communication) having more than one EP area,each socket-outlet or group of socket-outlets shall be marked, in accordance withClause 1.5, to identify the associated equipotential earthing system

NOTE: Adjacent socket-outlets constitute a group only if they are all contained within onecontiguous enclosure or panel

Socket-outlets shall be switched in all active conductors

NOTE: All isolated supply conductors are active conductors

shall comply with AS 3190 and shall have a rated residual current not exceeding —

(a) 10 mA for protection of low voltage circuits; and

(b) 100 mA for protection of extra-low voltage circuits

electrical area should be discriminatory in its operation, i.e an earth fault in any onesubcircuit should not cause interruption of the supply to other subcircuits

not more than 12 points Each RCD shall control the supply to socket-outlets in no morethan one patient location

NOTE: In the planning of the number of points to be controlled by an RCD, considerationshould be given to the type and number of equipment to be used and the need to minimizeinterruption of supply to any patient location

4.6.5 Indication If the location of any RCD is remote from the socket-outlets which itsupplies, the RCD shall be provided with a luminous indicator to show when power isavailable to the socket-outlets.

accordance with Clause 1.5, to indicate the points that it controls

permanently wired equipment, suitable access to the load circuit for testing the operation

of the RCD shall be provided The test facility shall be marked, in accordance withClause 1.5, ‘TEST ONLY’ and shall be accessible

A socket-outlet may be used where access to the socket-outlet is by the use of a tool

comply with the requirements of AS/NZS 4510

The isolated supply shall comprise the following:

(a) Isolating transformer

(b) Overload monitor, except where exempted by Clause 4.7.3

(c) Line isolation monitor

For New Zealand, approved resistance type monitoring systems shall apply Suitableresistance-type monitoring systems include systems that comply with VDE 0107

NOTE: The IEC is developing a Standard for resistance-type monitoring systems

with the requirements of AS 3000 and the manufacturer’s instructions, in a space orenclosure so that, in normal operation at the rated load, the temperature does not exceedthe maximum ambient temperature marked on the isolating transformer The isolatingtransformer manufacturer’s advice should be sought on installing an isolating transformer

in a space or enclosure so that the isolating transformer’s maximum temperature is notexceeded

Where an isolating transformer supplies two or more patient locations, duplicate alarmsand controls shall be provided where patient locations are not in direct visual contact

monitor to monitor the isolating transformer current

This Clause applies to all isolating transformers except those which, because of thecharacteristics of the load, are not likely to carry overload current, and which supply onlypermanently connected equipment

NOTE: The overload monitor may be combined with the line isolation monitor required byClause 4.7.4

isolation monitor (LIM) to monitor the prospective hazard current

It shall not be possible to deactivate the LIM without the use of a tool

NOTE: The LIM may be combined with the overload monitor required by Clause 4.7.3

Each LIM shall be identified (numbered or lettered) in a permanent manner whichidentifies the points, i.e socket-outlets or permanently wired equipment, with which it isassociated

shall be protected by a miniature overcurrent circuit-breaker complying with AS 3111.The rating of the overcurrent circuit-breaker shall not exceed the primary current rating ofthe isolating transformer

NOTE: This miniature overcurrent circuit-breaker may be the same device as the overload

4.7.6 System prospective hazard current The prospective hazard current of thesupply, LIM and circuit wiring, but not including other equipment intended for connection

to the circuit, shall not exceed 2 mA when measured in accordance with AS/NZS 4510

NOTES:

1 A metallic conduit provides some protection against electrical interference and may be usedprovided that it does not cause the prospective hazard current to exceed that permitted bythis Clause

2 The length of isolated supply circuits should be as short as practicable in order to minimizethe total prospective hazard current

12 points

NOTE: Separate supplies may need to be provided to each patient location in order to—

(a) reduce the size of the isolating transformer and the magnitude of the prospective hazardcurrent;

(b) limit the complexity of the installation; and(c) obviate any duplication of alarms and controls

only to permanently wired equipment, access for testing the operation of the LIM shall beprovided This facility shall be marked, in accordance with Clause 1.5, ‘TEST ONLY’ andshall be accessible The test facility shall be marked, in accordance with Clause 1.5, toidentify the LIM that it tests

A socket-outlet may be used where access to the socket-outlet is by means of a tool

a leakage-protected circuit shall be provided with an individual isolating switch that shalloperate in all live conductors

shall be affixed in each cardiac-protected electrical area, at a height approximately 2 mabove floor level, to indicate the status of the area

NOTE: Means for the recording thereon of the most recent test date and the authorized person’ssignature are also recommended

relevant testing and inspections listed in Appendix D, prior to commissioning of the area

APPENDIX A

RATIONALE FOR THE REQUIREMENTS OF THIS STANDARD

(Informative)

identify clearly the areas to which the Standard’s requirements are to be applied and toclarify the following:

(a) The type of medical procedure undertaken dictates the level of ‘electrical protection’necessary (see Notes to Clause 1.1)

(b) The extent of the body-protected or cardiac-protected areas has been defined in an

in an attempt to eliminate the likelihood of any mains-powered equipment in thearea being powered from an unprotected socket-outlet

(c) The provision of an EP area is only necessary when cardiac-type procedures areundertaken The definition and accompanying Figure 1.1 seek to identify the extent

of the EP area and to highlight the fact that the EP area (which requires bonding of

certain exposed metal items) does not extend to the dimensions of the

cardiac-protected area

the specialized wiring systems set out in this Standard

body-protected area are protected Such protection offers patient and operator protectionagainst mains shock without relying on equipment classification or maintenance

Protection against mains shock from permanently-wired medical electrical equipment isprovided either by isolation within the equipment or by protected supply wiring

Understanding of these concepts is greatly assisted by reference to the flow chart inAS/NZS 2500

Where installers wish to provide for a ready upgrade of body-protected areas (at a latertime) by installing earthing conductors to be utilized as equipotential terminals, theseconductors/terminals should not be made available until such upgrade is actually taken.That is, the facilities available in a body-protected area should not be confused by thepresence of equipotential facilities (to avoid staff confusion or error)

designed to facilitate ready restoration of normal supply in the event of RCD operation

and disposition

type of protection provided is considered valuable information for medical personnel

switching of isolated supplies

A3.6 Residual current devices

AS 3190 This is the level considered necessary to provide high-integrity protectionagainst mains shock in a health care environment

NOTE: Reference to AS/NZS 2500 will assist in the understanding of the extenuatingconditions likely to be present in such environments

pole for normal 240 V a.c supply) is seen as —

(a) facilitating easy conversion upgrade of areas to cardiac-protected areas (if required);and

(b) simplifying maintenance systems and procedures (i.e by having RCDs the samethroughout all areas)

number of 12 points to be controlled by one RCD This number has been selected toencourage RCD protection of as many outlets as possible (i.e economic encouragement

by minimizing the number of RCDs to be purchased), although attention is drawn to theneed to minimize interruption of supply to other patient locations

RCD

wired equipment, there needs to be some facility to test the RCD operation withoutinterfering significantly with equipment

required

instructions from manufacturers to ensure correct operation

and provides for continued operation (i.e avoids circuit-breaker tripping) with a reducednumber of connected devices

construction is required

Identification requirements are self-explanatory

against degradation of isolation by operation at levels in excess of rating

2 mA to make provision for the additional leakage which results from connectedequipment or appliances

area is most necessary for medical staff

installation has been checked for conformance to Section 3 of this Standard