AS/NZS 3108:1994

1 - AS / NZS 3108:1994 APPROVAL AND TEST SPECIFICATION - PARTICULAR REQUIREMENTS FOR ISOLATING TRANSFORMERS AND SAFETY ISOLATING
4 - PREFACE
7 - CONTENTS
9 - CHAPTER 1 GENERAL REQUIREMENTS
9 - 1 SCOPE
9 - 2 DEFINITIONS
10 - 2.1 Safety extra-low voltage (SELV)
10 - 2.2 Power transformer
10 - 2.3 Isolating transformer
10 - 2.4 Safety isolating transformer
10 - 2.5 Flush-type transformer
10 - 2.6 Associated transformer
10 - 2.7 Incorporated transformer
10 - 2.8 Transformer for specific use
10 - 2.9 Input winding
10 - 2.10 Output winding
10 - 2.11 Rated supply voltage
10 - 2.12 Rated supply voltage range
10 - 2.13 Rated frequency
10 - 2.14 Rated output current
11 - 2.15 Rated output voltage
11 - 2.16 Rated power factor
11 - 2.17 Rated output
11 - 2.18 No-load input
11 - 2.19 No-load output voltage
11 - 2.20 Short-circuit voltage
11 - 2.21 Power supply cord
11 - 2.22 Detachable part
11 - 2.23 Tool
11 - 2.24 Basic insulation
12 - 2.25 Supplementary insulation
12 - 2.26 Double insulation
12 - 2.27 Reinforced insulation
12 - 2.28 Class I transformer
12 - 2.29 Class II transformer
12 - 2.30 Class III transformer
12 - 2.31 Short-circuit proof transformer
13 - 2.32 Non-inherently short-circuit proof transformer
13 - 2.33 Inherently short-circuit proof transformer
13 - 2.34 Fail-safe transformer
13 - 2.35 Non-short-circuit proof transformer
13 - 2.36 Portable transformer
13 - 2.37 Hand-held transformer
13 - 2.38 Stationary transformer
13 - 2.39 All-pole disconnection
13 - 2.40 Thermal cutout
13 - 2.41 Self-resetting thermal cutout
13 - 2.42 Non-self-resetting thermal cutout
13 - 2.43 Overload release
13 - 2.44 Body
14 - 2.45 Accessible part
14 - 2.46 Rated ambient temperature
14 - 2.47 Clearance
14 - 2.48 Creepage distance
14 - 2.49 Working voltage
14 - 2.50 Pollution
14 - 2.51 Micro-environment
14 - 2.52 Degree of pollution in the micro-environment
14 - 2.53 Protective separation
15 - 2.54 Protective screening
15 - 3 GENERAL REQUIREMENTS
15 - 3.1 Design and construction
15 - 4 GENERAL NOTES ON TESTS
15 - 4.1 Type of tests
15 - 4.2 Sampling
15 - 4.3 Order of tests
15 - 4.4 Temperature
15 - 4.5 Test voltages
15 - 4.6 Position during tests
16 - 4.7 Test measurements
16 - 4.8 Transformers with a power supply cord
16 - 4.9 Class I transformers with parts of Class II construction
16 - 4.10 Flush-type transformers
16 - 4.11 Transformers for specific use
16 - 4.12 Associated transformers
17 - 4.13 IP 00 transformers
17 - 4.201 Electronic circuits associated with transformers
17 - 5 RATING
17 - 6 CLASSIFICATION
17 - 6.1 Electric shock protection
17 - 6.2 Short-circuit protection
17 - 6.3 Enclosure protection
17 - 6.4 Mobility
17 - 7 MARKING
17 - 7.1 General
18 - 7.2 Transformers with IP 00 protection or associated transformers
18 - 7.3 Transformers with adjustable supply voltages
18 - 7.4 Transformers with tapped or multiple output windings
19 - 7.5 Additional marking for short-circuit proof, non-short-circuit proof and fail-safe transformers
19 - 7.6 Terminals
19 - 7.7 Connection markings
19 - 7.8 Transformers with Type X, Y, and Z attachments
20 - 7.9 Symbols
21 - 7.10 Switches and regulating devices
21 - 7.11 Position of marking
22 - 7.12 Legibility and durability
22 - 8 PROTECTION AGAINST ELECTRIC SHOCK
22 - 8.1 Construction and enclosure
23 - 8.2 Prohibited connections
23 - 8.3 Mechanical strength
24 - 8.4 Shafts, handles, operating levers, knobs and the like
24 - 8.5 Insulation
24 - 8.6 Separation of input and output windings
25 - 8.7 Prohibited use of capacitors
25 - 9 CHANGE OF INPUT VOLTAGE SETTING
26 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
26 - 10.1 Output voltage
26 - 10.2 Confirmation of output markings
26 - 11 NO-LOAD OUTPUT VOLTAGE
26 - 12 SHORT-CIRCUIT VOLTAGE
26 - 13 HEATING
26 - 13.1 Temperature during normal use
31 - 14 SHORT-CIRCUIT AND OVERLOAD PROTECTION
31 - 14.1 General
33 - 15 MECHANICAL STRENGTH
33 - 15.1 General
34 - 15.2 Impact test
34 - 15.3 Drop test for portable transformers without integral pins
34 - 15.4 Transformers with integral pins
34 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
34 - 16.1 Enclosures
35 - 16.2 Effects of humidity
35 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
35 - 17.1 General
37 - 18 CONSTRUCTION
37 - 18.1 General
37 - 18.2 Materials
38 - 18.3 Permissible types
38 - 18.4 Contact between accessible metal and conduits
38 - 18.5 Removal and replacement of insulation
38 - 18.6 Class I and Class II transformers
39 - 18.7 Supplementary and reinforced insulation
39 - 18.8 Separation of input and output terminals
39 - 18.9 Fixing of handles, levers and the like
39 - 18.10 Fixing of covers
40 - 18.11 Transformers provided with pins
40 - 18.12 Protection index
40 - 18.13 Transformers with a particular protection index
40 - 18.14 Class I transformers
40 - 18.201 Output facilities
41 - 19 COMPONENTS
41 - 19.1 General
41 - 19.2 Switches
41 - 19.3 Socket-outlets
41 - 19.4 Breaking capacity of thermal cutouts and overload releases
42 - 19.5 Prohibition of self-resetting thermal cutouts
42 - 19.6 Prohibited components
42 - 19.7 Operation of overload protection devices
42 - 19.201 Mounting of output protection
42 - 20 INTERNAL WIRING
42 - 20.1 Protection
42 - 20.2 Openings
42 - 20.3 Bare conductors
42 - 20.4 Fixing of internal wiring
42 - 20.5 Insulated conductors
43 - 21 SUPPLY CONNECTION AND EXTERNAL FLEXIBLE CABLES AND CORDS
43 - 21.1 Separate entries for input and output wiring
43 - 21.2 Stationary transformers
43 - 21.3 Portable transformers
43 - 21.4 Cables and cords used for connections
43 - 21.5 Cross-sectional area of power supply flexible cables and cords
44 - 21.6 Fitting of plugs
44 - 21.7 Power supply cord attachment
48 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
48 - 22.1 Types of fixings
48 - 22.2 Screws and nuts which clamp external conductors
49 - 22.3 Compatibility between terminals and conductors
49 - 22.4 Clamping arrangements for terminals for Type X attachment
49 - 22.5 Clamping of conductors
50 - 22.6 Grouping of terminals
50 - 22.7 Terminal blocks and similar devices
50 - 22.8 Terminals for Type X attachment
50 - 22.9 Design and position of terminals
50 - 22.10 Dimensions of pillar terminals
51 - 22.11 Dimensions of screw terminals
52 - 22.12 Dimensions of stud terminals
53 - 22.13 Mechanical strength of terminals
53 - 22.14 Prohibition of contact between terminals and accessible metal
53 - 23 PROVISION FOR EARTHING
53 - 23.1 General
54 - 23.2 Design of earthing terminal
54 - 23.3 Prevention of corrosion of earthing terminal
54 - 23.4 Prohibition of earthing of socket-outlets
54 - 23.5 Resistance of earthing connection
55 - 24 SCREWS AND CONNECTIONS
55 - 24.1 Mechanical strength
56 - 24.2 Engagement of thread
56 - 24.3 Contact pressure of electrical connections
56 - 24.4 Space-threaded and thread-cutting screws
57 - 24.5 Use of screws and rivets
57 - 25 CREEPAGE DISTANCES, CLEARANCES AND DISTANCES THROUGH INSULATION
57 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
57 - 26.1 Resistance of external parts of insulating material to heat
57 - 26.2 Resistance of external parts of insulating material to fire
61 - 26.3 Parts of insulating material retaining live parts in position
62 - 26.4 Resistance of insulating material to abnormal heat
62 - 26.5 Resistance to tracking
62 - 27 RESISTANCE TO RUSTING
63 - APPENDIX 1A - TESTS DURING PRODUCTION
63 - 1A1 GENERAL
63 - 1A2 EARTHING CONTINUITY TEST
63 - 1A3 CHECKING OF NO-LOAD OUTPUT VOLTAGE AND NO-LOAD CURRENT
63 - 1A4 ELECTRIC STRENGTH TEST
63 - 1A5 CHECKING OF MOUNTING OF PROTECTIVE DEVICES
64 - APPENDIX 1B - EXAMPLES OF CONSTRUCTION OF WINDINGS TO BE USED AS A GUIDE FOR CLAUSE 8.6
64 - 1B1 COIL- FORMERS
65 - 1B2 WINDINGS
67 - APPENDIX IC - EXAMPLES OF POINTS OF APPLICATION OF TEST VOLTAGES
69 - APPENDIX 1D - MEASUREMENT OF CREEPAGE DISTANCES AND CLEARANCES
74 - APPENDIX 1E - EXAMPLES OF POINTS OF MEASUREMENT OF CREEPAGE DISTANCES AND CLEARANCES
76 - CHAPTER 2 SUPPLEMENTARY REQUIREMENTS FOR ISOLATING TRANSFORMERS FOR GENERAL USE AND SHAVER TRANSFORMERS
76 - INTRODUCTION
76 - 1 SCOPE
76 - 2 DEFINITIONS
76 - 2.101 Shaver supply transformer
76 - 2.102 Shaver supply unit
76 - 3 GENERAL REQUIREMENTS
76 - 4 GENERAL NOTES ON TESTS
76 - 5 RATING
76 - 5.101 Rated output voltage
77 - 5.102 Rated output
77 - 5.103 Rated input voltage
77 - 6 CLASSIFICATION
77 - 7 MARKING
77 - 7.1 General
77 - 7.9 Symbols
77 - 7.11 Position of marking
77 - 8 PROTECTION AGAINST ELECTRIC SHOCK
77 - 8.1 Construction and enclosure
78 - 8.2 Prohibited connections
78 - 9 CHANGE OF INPUT VOLTAGE SETTING
78 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
78 - 11 NO-LOAD OUTPUT VOLTAGE
78 - 11.101 Maximum no-load voltage
78 - 11.102 Difference between output voltages at no-load and at rated output
78 - 12 SHORT- CIRCUIT VOLTAGE
78 - 13 HEATING
79 - 14 SHORT-CIRCUIT AND OVERLOAD PROTECTION
79 - 14.1 General
79 - 15 MECHANICAL STRENGTH
79 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
79 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
79 - 18 CONSTRUCTION
79 - 18.6 Class I and Class II transformers
79 - 18.7 Supplementary and reinforced insulation
79 - 18.101 Mounting boxes
79 - 18.102 Output windings
79 - 18.103 Separation of output windings and connection to socket- outlet
79 - 18.104 Socket- outlets
79 - 18.105 Replacement of non- self- resetting thermal cutouts
80 - 19 COMPONENTS
80 - 19.2 Switches
80 - 19.5 Prohibition of self-resetting thermal cutouts
80 - 20 INTERNAL WIRING
80 - 21 SUPPLY CONNECTION AND EXTERNAL FLEXIBLE CABLES AND CORDS
80 - 21.4 Cables and cords used for connections
80 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
80 - 22.5 Clamping of conductors
80 - 22.8 Terminals for Type X attachment
81 - 23 PROVISION FOR EARTHING
81 - 23.4 Prohibition of earthing of socket-outlets
81 - 24 SCREWS AND CONNECTIONS
81 - 25 CREEPAGE DISTANCES AND CLEARANCES AND DISTANCES THROUGH INSULATION
81 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
81 - 27 RESISTANCE TO RUSTING
82 - CHAPTER 3 SUPPLEMENTARY REQUIREMENTS FOR SAFETY ISOLATING TRANSFORMERS
82 - INTRODUCTION
83 - SECTION 1 SAFETY ISOLATING TRANSFORMERS FOR GENERAL USE
83 - 1 SCOPE
83 - 2 DEFINITIONS
83 - 3 GENERAL REQUIREMENTS
83 - 4 GENERAL NOTES ON TESTS
83 - 5 RATING
83 - 5.101 Rated output voltage
83 - 5.102 Maximum rated output
83 - 6 CLASSIFICATION
83 - 7 MARKING
83 - 7.101 Instruction sheet
84 - 8 PROTECTION AGAINST ELECTRIC SHOCK
84 - 8.1 Construction and enclosure
84 - 9 CHANGE OF INPUT VOLTAGE SETTING
84 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
84 - 11 NO-LOAD OUTPUT VOLTAGE
84 - 11.101 Maximum no-load output voltage
84 - 11.102 Difference between output voltage at no- load and at rated output
85 - 12 SHORT-CIRCUIT VOLTAGE
85 - 13 HEATING
85 - 14 SHORT-CIRCUIT AND OVERLOAD PROTECTION
85 - 15 MECHANICAL STRENGTH
85 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
85 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
85 - 18 CONSTRUCTION
85 - 18.6 Class I and Class II Transformers
85 - 18.7 Supplementary and reinforced insulation
85 - 19 COMPONENTS
85 - 20 INTERNAL WIRING
85 - 21 SUPPLY CONNECTION AND SUPPLY FLEXIBLE CABLES OR CORDS
85 - 21.4 Cables and cords used for connections
86 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
86 - 22.5 Clamping of conductors
86 - 22.8 Terminals for Type X attachment
86 - 23 PROVISION FOR EARTHING
86 - 24 SCREWS AND CONNECTIONS
86 - 25 CREEPAGE DISTANCES AND CLEARANCES AND DISTANCES THROUGH INSULATION
86 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
86 - 27 RESISTANCE TO RUSTING
87 - SECTION 2 TRANSFORMERS FOR TOYS
87 - 1 SCOPE
87 - 2 DEFINITIONS
87 - 2.101 Transformer for toys
87 - 3 GENERAL REQUIREMENTS
87 - 4 GENERAL NOTES ON TESTS
87 - 5 RATING
87 - 5.101 Rated output voltage
87 - 5.102 Rated output
87 - 5.103 Rated supply voltage
87 - 6 CLASSIFICATION
87 - 7 MARKING
87 - 7.1 General
87 - 7.9 Symbols
88 - 8 PROTECTION AGAINST ELECTRIC SHOCK
88 - 8.1 Construction and enclosure
88 - 8.1 Construction and enclosure
88 - 9 CHANGE OF INPUT VOLTAGE SETTING
88 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
88 - 11 NO-LOAD OUTPUT VOLTAGE
88 - 11.101 Maximum no-load output voltage
88 - 11.102 Difference between output voltage at no-load and at rated output
88 - 12 SHORT-CIRCUIT VOLTAGE
89 - 13 HEATING
89 - 14 SHORT-CIRCUIT AND OVERLOAD PROTECTION
89 - 14.1 General
89 - 14.3 Non- inherently short-circuit proof transformers
89 - 15 MECHANICAL STRENGTH
90 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
90 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
90 - 18 CONSTRUCTION
90 - 18.1 General
90 - 18.6 Class II transformers
90 - 18.7 Supplementary and reinforced insulation
90 - 18.101 Transformers with a. c. terminals in the output circuit
91 - 19 COMPONENTS
91 - 19.3 Socket outlets
91 - 19.4 Breaking capacity of thermal cut- outs and overload releases
91 - 19.101 Non- self- resetting thermal cutouts and overload releases
91 - 19.102 Control devices
91 - 20 INTERNAL WIRING
92 - 21 SUPPLY CONNECTION AND EXTERNAL FLEXIBLE CABLES AND CORDS
92 - 21.4 Cables and cords used for connection
92 - 21.5 Cross-sectional area of power supply flexible cables and cords
92 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
92 - 22.5 Clamping of conductors
92 - 22.8 Terminals for Type X attachment
92 - 23 PROVISION FOR EARTHING
92 - 24 SCREWS AND CONNECTIONS
92 - 25 CREEPAGE DISTANCES AND CLEARANCES AND DISTANCES THROUGH INSULATION
92 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
92 - 27 RESISTANCE TO RUSTING
93 - SECTION 3 BELL TRANSFORMERS
93 - 1 SCOPE
93 - 2 DEFINITIONS
93 - 2.101 Bell transformer
93 - 3 GENERAL REQUIREMENTS
93 - 4 GENERAL NOTES ON TESTS
93 - 4.10 Flush-type transformers
93 - 4.10 Flush-type transformers
93 - 5 RATING
93 - 5.101 Rated output voltage
93 - 5.102 Rated output current
93 - 5.103 Rated supply voltage
93 - 5.104 Rated output power
93 - 6 CLASSIFICATION
94 - 6.2 Short-circuit protection
94 - 6.101 Method of mounting
94 - 7 MARKING
94 - 7.1 General
94 - 7.9 Symbols
94 - 8 PROTECTION AGAINST ELECTRIC SHOCK
94 - 8.1 Construction and enclosure
94 - 8.201 Protection against contact with windings and live parts
94 - 9 CHANGE OF INPUT VOLTAGE SETTING
94 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
95 - 11 NO-LOAD OUTPUT VOLTAGE
95 - 11.101 Maximum no-load output voltage
95 - 11.102 Difference between output voltage at no- load and at rated output
95 - 12 SHORT-CIRCUIT VOLTAGE
95 - 13 HEATING
96 - 14 SHORT-CIRCUIT AND OVERLOAD PROTECTION
96 - 14.1 General
96 - 14.1 General
96 - 15 MECHANICAL STRENGTH
96 - 15.2 Impact test
96 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
96 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
96 - 18 CONSTRUCTION
96 - 18.1 General
96 - 18.1 General
97 - 18.6 Class II transformers
97 - 18.7 Supplementary and reinforced insulation
97 - 18.13 Transformers with a particular protection index
97 - 18.13 Transformers with a particular protection index
97 - 18.101 Transformers mounted in consumer distribution boxes
97 - 19 COMPONENTS
97 - 19.2 Switches
97 - 19.2 Switches
97 - 19.4 Breaking capacity of thermal cutouts and overload releases
97 - 19.4 Breaking capacity of thermal cutouts and overload releases
98 - 19.5 Prohibition of self-resetting thermal cutouts
98 - 20 INTERNAL WIRING
98 - 21 SUPPLY CONNECTION AND EXTERNAL FLEXIBLE CABLES AND CORDS
98 - 21.1 Separate entries for input and output wiring
98 - 21.4 Cables and cords used for connection
99 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
99 - 22.5 Clamping of conductors
99 - 22.8 Terminals for Type X attachment
99 - 23 PROVISION FOR EARTHING
99 - 24 SCREWS AND CONNECTIONS
99 - 24.2 Engagement of thread
99 - 25 CREEPAGE DISTANCES AND CLEARANCES AND DISTANCES THROUGH INSULATION
99 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
99 - 27 RESISTANCE TO RUSTING
100 - SECTION 4 TRANSFORMERS FOR CLASS III HANDLAMPS
100 - 1 SCOPE
100 - 2 DEFINITIONS
100 - 2.101 Transformers for Class III handlamps
100 - 3 GENERAL REQUIREMENTS
100 - 4 GENERAL NOTES ON TESTS
100 - 5 RATING
100 - 5.101 Rated output voltage
100 - 6 CLASSIFICATION
100 - 7 MARKING
100 - 7.1 General
100 - 7.9 Symbols
101 - 8 PROTECTION AGAINST ELECTRICAL SHOCK
101 - 8.1 Construction and enclosure
101 - 9 CHANGE OF INPUT VOLTAGE SETTING
101 - 10 OUTPUT VOLTAGE AND OUTPUT CURRENT UNDER LOAD
101 - 11 NO-LOAD OUTPUT VOLTAGE
101 - 11.101 Maximum no- load output voltage
101 - 11.102 Difference between output voltage at no- load and the voltage at half the rated output
101 - 12 SHORT- CIRCUIT VOLTAGE
101 - 13 HEATING
102 - 14 SHORT- CIRCUIT AND OVERLOAD PROTECTION
102 - 15 MECHANICAL STRENGTH
102 - 16 PROTECTION AGAINST HARMFUL INGRESS OF WATER AND MOISTURE
102 - 17 INSULATION RESISTANCE AND ELECTRIC STRENGTH
102 - 18 CONSTRUCTION
102 - 18.6 Class II transformers
102 - 18.7 Supplementary and reinforced insulation
102 - 19 COMPONENTS
102 - 20 INTERNAL WIRING
102 - 21 SUPPLY CONNECTION AND EXTERNAL FLEXIBLE CABLES AND CORDS
102 - 21.4 Cables and cords used for connections
103 - 22 TERMINALS FOR EXTERNAL CONDUCTORS
103 - 22.5 Clamping of conductors
103 - 22.8 Terminals for Type X attachment
103 - 23 PROVISION FOR EARTHING
103 - 24 SCREWS AND CONNECTIONS
103 - 25 CREEPAGE DISTANCES AND CLEARANCES DISTANCES THROUGH INSULATION
103 - 26 RESISTANCE TO HEAT, ABNORMAL HEAT, FIRE AND TRACKING
103 - 27 RESISTANCE TO RUSTING
110 - ANNEX A - VARIANT TO CLAUSE 22, TERMINALS FOR EXTERNAL CONDUCTORS
110 - 22.3 Compatibility between terminals and conductors
110 - 22.10 Dimensions of pillar terminals
111 - 22.11 Dimensions of screw terminals
111 - 22.12 Dimensions of stud terminals
111 - 22.13 Mechanical strength of terminals
116 - ANNEX B - LIST OF VARIATIONS BETWEEN THIS STANDARD AND IEC 742:1983

Specifies essential safety requirements for approval and test purposes. It contains general requirements and particular requirements for specific transformers.

This Standard is applicable to stationary or portable, single-phase or polyphase, air cooled isolating and safety isolating transformers, associated or otherwise, having a rated supply voltage not exceeding 1000 V a.c. and rated frequency not exceeding 500 Hz, the rated output not exceeding:(a) For isolating transformers: (i) 25 kV.A for single-phase transformers. (ii) 40 kV.A for polyphase transformers.(b) For safety isolating transformers: (i) 10 kV.A for single-phase transformers. (ii) 16 kV.A for polyphase transformers.The no-load and rated output voltages do not exceed:(A) For isolating transformers, 1000 V a.c. and 1000 +2 V unsmoothed d.c.(B) For safety isolating transformers, 50 V a.c. r.m.s., or 120 V ripple free d.c. between conductors or between any conductor and earth.Rated values, appropriate to each type of transformer, are indicated in Chapter 2 and Chapter 3.NOTES:This Standard is applicable to those isolating transformers used when the installation rules call for the separation of circuits for the supply of equipment (for example, shavers, portable tools and lawn mowers) or of certain parts of the circuit. This Standard is applicable to safety isolating transformers used for the supply of circuits for safety extra-low voltage equipment (for example, toys, bells, portable tools and handlamps). This Standard applies to transformers associated with specific items of equipment, to the extent indicated by other Australian or Australian/New Zealand Standards. This Standard is applicable to dry type or encapsulated transformers. It is not applicable to transformers filled with oil, sand or similar substances. In locations where special environmental conditions prevail, particular requirements may be necessary in accordance with AS 3000 in Australia and with the Electricity Regulations in New Zealand.

AS 3108 first published in Australia in part as AS C126-1939.
Second edition 1958.
AS C167 first published 1962.
Revised and redesignated AS 3167-1981 (withdrawn 1987).
AS C126-1958 revised and redesignated AS 3126-1981 (withdrawn 1989).
AS 3126-1981 and AS 3167-1981 revised and redesignated AS 3108.1-1984, AS 3108.2-1984 and AS 3108.3-1984.
Revised, amalgamated and redesignated AS 3108-1990.
First published in New Zealand as NZS/AS 3108:1990.
Jointly revised and designated as Joint Standard AS/NZS 3108:1994.