IEC 60950:1999

Foreword
Introduction
0. Principles of safety
0.1 General principles of safety
0.2 Hazards
0.3 Materials and components
1. General
1.1 Scope
1.2 Definitions
1.3 General requirements
1.4 General conditions for tests
1.5 Components
1.6 Power interface
1.7 Marking and instructions
2. Protection from hazards
2.1 Protection from electric shock and energy
      hazards
2.2 SELV circuits
2.3 TNV circuits
2.4 Limited current circuits
2.5 Limited power sources
2.6 Provisions for earthing and bonding
2.7 Overcurrent and earth fault protection in primary
      circuits
2.8 Safety interlocks
2.9 Electrical insulation
2.10 Clearances, creepage distances and distances through
      insulation
3. Wiring, connections and supply
3.1 General
3.2 Connection to a.c. mains supplies
3.3 Wiring terminals for connections of external conductors
3.4 Disconnection from the a.c. mains supply
3.5 Interconnection of equipment
4. Physical requirements
4.1 Stability
4.2 Mechanical strength
4.3 Design and construction
4.4 Protection against hazardous moving parts
4.5 Thermal requirements
4.6 Openings in enclosures
4.7 Resistance to fire
5. Electrical requirements and simulated abnormal conditions
5.1 Touch current and protective conductor current
5.2 Electric strength
5.3 Abnormal operating and fault conditions
6. Connection to telecommunication networks
6.1 Protection of telecommunication network service personnel,
      and users of other equipment connected to the network,
      from hazards in the equipment
6.2 Protection of equipment users from overvoltages on
      telecommunication networks
6.3 Protection of telecommunication wiring system from
      overheating
Annex A (normative) Tests for resistance to heat
and fire
A.1 Flammability test for fire enclosures of movable
       equipment having a total mass exceeding 18 kg,
       and of stationary equipment (see 4.7.3.2)
A.2 Flammability test for fire enclosures of movable
       equipment having a total mass not exceeding 18 kg
       and for material and components located inside
       fire enclosures (see 4.7.3.2 and 4.7.3.4)
A.3 High current arcing ignition test (see 4.7.3.2)
A.4 Hot wire ignition test (see 4.7.3.2)
A.5 Hot flaming oil test (see 4.6.2)
A.6 Flammability tests for classifying materials
       V-0, V-1 or V-2
A.7 Flammability test for classifying foamed materials
       HF-1, HF-2 or HBF
A.8 Flammability test for classifying materials HB
A.9 Flammability test for classifying materials 5V
A.10 Stress relief conditioning (see 4.2.7)
Annex B (normative) Motor tests under abnormal conditions
(see 4.7.2.2 and 5.3.2)
B.1 General requirements
B.2 Test conditions
B.3 Maximum temperatures
B.4 Running overload test
B.5 Locked-rotor overload test
B.6 Running overload test for d.c. motors in secondary
       circuits
B.7 Locked-rotor overload test for d.c. motors in
       secondary circuits
B.7.1 Test procedure
B.7.2 Alternative test procedure
B.7.3 Electric strength test
B.8 Test for motors with capacitors
B.9 Test for three-phase motors
B.10 Test for series motors
Annex C (normative) Transformers (see 1.5.4 and 5.3.3)
C.1 Overload test
C.2 Insulation
Annex D (normative) Measuring instruments for touch-
current tests (see 5.1.4)
D.1 Measuring instrument
D.2 Alternative measuring instrument
Annex E (normative) Temperature rise of a winding (see
1.4.13 and 4.5.1)
Annex F (normative) Measurement of clearances and
creepage distances (see 2.10)
Annex G (normative) Alternative method for determining
minimum clearances
G.1 Summary of the procedure for determining minimum
       clearances
G.2 Determination of mains transient voltage
G.3 Determination of telecommunication network transient
       voltage
G.4 Determination of required withstand voltage
G.5 Measurement of transient levels
G.6 Determination of minimum clearances
Annex H (normative) Ionizing radiation (see 4.3.13)
Annex J (normative) Table of electrochemical potentials
(see 2.6.5.6)
Annex K (normative) Thermal controls (see 1.5.3 and
5.3.7)
K.1 Making and breaking capacity
K.2 Thermostat reliability
K.3 Thermostat endurance test
K.4 Temperature limiter endurance
K.5 Thermal cutout reliability
K.6 Stability of operation
Annex L (normative) Normal load conditions for some
types of electrical business equipment (see 1.2.2.1 and
4.5.1)
L.1 Typewriters
L.2 Adding machines and cash registers
L.3 Erasers
L.4 Pencil sharpeners
L.5 Duplicators and copy machines
L.6 Motor-operated files
L.7 Other business equipment
Annex M (normative) Criteria for telephone ringing
signals (see 2.3.1)
M.1 Introduction
M.2 Method A
M.3 Method B
M.3.1 Ringing signal
M.3.1.1 Frequency
M.3.1.2 Voltage
M.3.1.3 Cadence
M.3.1.4 Single fault current
M.3.2 Tripping device and monitoring voltage
M.3.2.1 Conditions for use of a tripping device or a
        monitoring voltage
M.3.2.2 Tripping device
M.3.2.3 Monitoring voltage
Annex N (normative) Impulse test generators (see 2.10.3.4,
6.2.2.1 and G.5)
Annex P (normative) Normative references
Annex Q (informative) Bibliography
Annex R (informative) Examples of requirements for quality
control programmes
R.1 Minimum separation distances for unpopulated coated
       printed boards (see 2.10.6)
R.2 Reduced clearances
Annex S (informative) Procedure for impulse testing (see
6.2.2.3)
S.1 Test equipment
S.2 Test procedure
S.3 Examples of waveforms during impulse testing
Annex T (informative) Guidance on protection against ingress
of water (see 1.1.2)
Annex U (normative) Insulated winding wires for use without
interleaved insulation (see 2.10.5.4)
U.1 Wire construction
U.2 Type tests
U.2.1 Electric strength
U.2.2 Flexibility and adherence
U.2.3 Heat shock
U.2.4 Retention of electric strength after bending
U.3 Tests during manufacture
U.3.1 Routine testing
U.3.2 Sampling tests
Annex V (normative) AC power distribution systems (see
1.6.1)
V.1 Introduction
V.2 TN power systems
V.3 TT power systems
V.4 IT power systems
Annex W (informative) Summation of touch currents
W.1 Touch current from electronic circuits
W.1.1 Floating circuits
W.1.2 Earthed circuits
W.2 Interconnection of several equipments
W.2.1 Isolation
W.2.2 Common return, isolated from earth
W.2.3 Common return, connected to protective earth
Annex X (informative) Maximum heating effect in transformer
tests (see C.1)
X.1 Determination of maximum input current
X.2 Overload test procedure
Figures
Tables

Applies to information technology equipment including electricalbusiness equipment and associated equipment, with a rated voltagenot exceeding 600 V.Specifies requirements intended to ensure safety for the operatorand layman who may come into contact with the equipment and, wherespecifically stated, for service personnel. Supersedes IEC 60380 and60435.Please also refer to Guide 112 for using the current editions of IEC 60065 and IEC 60950 in evaluating the safety of multimedia equipment