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1.1 Scope

1.1.1 Equipment covered by this standard This standard is applicable to mains-powered or battery-powered information technology equipment, including electrical business equipment and associated equipment, with a RATED VOLTAGE not exce eding 600 V and designed to be installed in accordance with the Canadian Electrical Code, Part 1, CSA C22.2 No. 0; and the National Electrical Code, NFPA 70.

The standard is also applicable to equipment, unless otherwise identified by a marking of instructions, designed to be installed in accordance with Article 645 of the National Electrical Code, NFPA 70, and the Standard for the Protection of Electronic Computer Data-Processing Equipment, NFPA 75.

See annex NAE for examples of and references to regulatory requirements that may apply to this equipment.

This standard is also applicable to such information technology equipme nt designed and intended to be connected directly to a TELECOMMUNICATION NETWORK, regardless of the source of power.

It is also applicable to such information technology equipment designed to use the AC MAINS SUPPLY as a telecommunication transmis sion medium (see note 4 of clause 6).

This standard specifies requirements intended to reduce risks of fire, electric shock or injury for the OPERATOR and layman who may come into contact with the equipment and, where specifically stated, for SERVICE PERSONNEL.

This standard is intended to reduce such risks with respect to installed equipment, whether it consists of a system of inte rconnected units or independent units, subject to installing, operating and maintaining the equipment in the manner prescribed by the manufacturer.

Examples of equipment which is in the scope of this standard are: accounting machines bookkeeping machines calculators cash registers copying machines data circuit terminating equipment data preparation equipment data processing equipment data terminal equipment dictation equipment document shredding machines duplicators electrically operated drawing machines erasers facsimile equipment key telephone systems magnetic tape handlers mail processing machines micrographic office equipment modems monetary processing machines including automated teller (cash dispensing) machines motor-operated files PABX's paper jogging machines paper trimmers (punchers, cutting machines, separators) pencil sharpeners personal computers photoprinting equipment plotters point of sale terminals including associated electronic scales postage machines public information terminals staplers telephone answering machines telephone sets text processing equipment typewriters visual display units

This list is not intended to be comprehensive, and equipment that is not listed is not necessarily excluded from the scope.

Equipment complying with the relevant requirements in this standard is considered suitable for use with process control equipment, automatic test equipment and similar systems requiring information processing facilities. However, this standard does not include requirements for performance or functional characteristics of equipment.

1.1.2 Additional requirements Requirements additional to those specified in this standard may be necessary for: - equipment intended for operation in special environments, for example, extremes of temperature; excessive dust, moisture or vibration; flammable gases; and corrosive or explosive atmospheres; - electromedical applications with physical connections to the patient; - equipment intended to be used in vehicles, on board ships or aircraft, in tropical countries, or at altitudes greater than 2 000 m; - equipment intended for use where ingress of water is possible; for guidance on such requirements and on relevant testing, see annex T.

NOTE

Attention is drawn to the fact that authorities of some countries impose additional requirements.,,

1.1.3 Exclusions This standard does not apply to: - support equipment, such as air conditioning, fire detection or fire extinguishing systems; - power supply systems, such as motor-generator sets, battery backup s ystems and transformers, which are not an integral part of the equipment; - building installation wiring; - devices requiring no electric power.

CONTENTS

PREFACE - 10

FOREWORD (CSA) - 13

FOREWORD (UL) - 14

FOREWORD - 15

INTRODUCTION - 17 0 Principles of safety - 17 0.1 General principles of safety - 17 0.2 Hazards - 18 0.3 Materials and components - 22 1 General - 23 1.1 Scope - 23 1.2 Definitions - 25 1.3 General requirements - 37 1.4 General conditions for tests - 39 1.5 Components - 44 1.6 Power interface - 47 1.7 Markings and instructions - 48 2 Protection from hazards - 56 2.1 Protection from electric shock and energy hazards - 56 2.2 SELV circuits - 64 2.3 TNV circuits - 67 2.4 Limited current circuits - 72 2.5 Limited power sources - 74 2.6 Provisions for earthing and bonding - 76 2.7 Overcurrent and earth fault protection in primary circuits - 85 2.8 Safety interlocks - 88 2.9 Electrical insulation - 91 2.10 Clearances, creepage distances and distances through insulation - 97 3 Wiring, connections and supply - 118 3.1 General - 118 3.2 Connection to a.c. mains supplies - 122 3.3 Wiring terminals for connection of external conductors - 129 3.4 Disconnection from the a.c. mains supply - 133 3.5 Interconnection of equipment - 136 3.6 Special considerations for equipment connected to a centralized d.c. power system

DC mains voltages - 137 4 Physical requirements - 138 4.1 Stability - 138 4.2 Mechanical strength - 139 4.3 Design and construction - 144 4.4 Protection against hazardous moving parts - 150 4.5 Thermal requirements - 152 4.6 Openings in enclosures - 155 4.7 Resistance to fire - 164 5 Electrical requirements and simulated abnormal conditions - 172 5.1 Touch current and protective conductor current - 172 5.2 Electric strength - 182 5.3 Abnormal operating and fault conditions - 186 6 Connection to telecommunication networks - 191 6.1 Protection of telecommunication network service personnel, and u sers of other equipment connected to the network, from hazards in the equipment - 191 6.2 Protection of equipment users from overvoltages on telecommunication networks - 194 6.3 Protection of the telecommunication wiring system from overheating - 198 6.4 Protection against overvoltage from power line crosses - 199 6.5 Acoustic tests - 202

Annex A (normative) Tests for resistance to heat and fire A.1 Flammability test for fire enclosures of movable equipment hav ing a total mass exceeding 18 kg, and of stationary equipment (see 4.7.3.2) - 206 A.1.1 Samples - 206 A.1.2 Conditioning of samples - 206 A.1.3 Mounting of samples - 207 A.1.4 Test flame - 207 A.1.5 Test procedure - 207 A.1.6 Compliance criteria - 207 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) - 207 A.2.1 Samples - 207 A.2.2 Conditioning of samples - 208 A.2.3 Mounting of samples - 208 A.2.4 Test flame - 208 A.2.5 Test procedure - 208 A.2.6 Compliance criteria - 209 A.2.7 Alternative test - 209 A.3 High current arcing ignition test (see 4.7.3.2) - 209 A.3.1 Samples - 209 A.3.2 Test circuit - 209 A.3.3 Test electrodes - 210 A.3.4 Test procedure - 211 A.3.5 Compliance criteria - 211 A.4 Hot wire ignition test (see 4.7.3.2) - 211 A.4.1 Samples - 211 A.4.2 Test circuit - 211 A.4.3 Mounting of samples - 211 A.4.4 Test procedure - 212 A.4.5 Compliance criterion - 213 A.5 Hot flaming oil test (see 4.6.2) - 213 A.5.1 Mounting of samples - 213 A.5.2 Test procedure - 213 A.5.3 Compliance criterion - 213 A.6 Flammability tests for classifying materials V-0, V-1 or V-2 - 213 A.6.1 Samples - 213 A.6.2 Conditioning of samples - 214 A.6.3 Mounting of samples - 214 A.6.4 Test procedure - 214 A.6.5 Compliance criteria - 215 A.6.6 Permitted retest - 215 A.7 Flammability test for classifying foamed materials HF-1, HF-2 or HBF - 215 A.7.1 Samples - 215 A.7.2 Conditioning of samples - 216 A.7.3 Test procedure - 216 A.7.4 Compliance criteria - 216 A.7.5 Compliance criteria, HF-2 - 217 A.7.6 Compliance criteria, HF-1 - 217 A.7.7 Compliance criteria, HBF - 217 A.7.8 Permitted retest, HF-1 or HF-2 - 217 A.7.9 Permitted retest, HBF - 218 A.8 Flammability test for classifying materials HB - 218 A.8.1 Samples - 218 A.8.2 Conditioning of samples - 218 A.8.3 Mounting of samples - 218 A.8.4 Test procedure - 219 A.8.5 Compliance criteria - 220 A.8.6 Permitted retest - 220 A.9 Flammability test for classifying materials 5V - 220 A.9.1 Samples - 220 A.9.2 Conditioning of samples - 220 A.9.3 Test flame - 221 A.9.4 Test procedure, test bars - 221 A.9.5 Test procedure, test plaques - 222 A.9.6 Compliance criteria - 223 A.9.7 Permitted retest - 223 A.10 Stress relief conditiioning (see 4.2.7) - 223

Annex B (normative) Motor tests under abnormal conditions (see 4.7.2.2 and 5.3.2) B.1 General requirements - 224 B.2 Test conditions - 224 B.3 Maximum temperatures - 225 B.4 Running overload test - 227 B.5 Locked-rotor overload test - 227 B.6 Running overload test for d.c. motors in secondary circuits - 228 B.7 Locked-rotor overload test for d.c. motors in secondary circuits - 229 B.7.1 Test procedure - 229 B.7.2 Alternative test procedure - 229 B.7.3 Electric strength test - 229 B.8 Test for motors with capacitors - 229 B.9 Test for three-phase motors - 230 B.10 Test for series motors - 230

Annex C (normative) Transformers (see 1.5.4 and 5.3.3) C.1 Overload test - 231 C.2 Insulation - 233

Annex D (normative) Measuring instruments for touch-current tests (see 5.1.4) D.1 Measuring instrument - 235 D.2 Alternative measuring instrument - 236

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 - 247 G.2 Determination of mains transient voltage - 248 G.3 Determination of telecommunication network transient voltage - 249 G.4 Determination of required withstand voltage - 249 G.5 Measurement of transient levels - 250 G.6 Determination of minimum clearances - 251

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 - 257 K.2 Thermostat reliability - 257 K.3 Thermostat endurance test - 258 K.4 Temperature limiter endurance - 258 K.5 Thermal cut-out reliability - 258 K.6 Stability of operation - 258

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 - 259 L.2 Adding machines and cash registers - 259 L.3 Erasers - 259 L.4 Pencil sharpeners - 259 L.5 Duplicators and copy machines - 260 L.6 Motor-operated files - 260 L.7 Other business equipment - 260

Annex M (normative) Criteria for telephone ringing and other sign als (see 2.3.1) M.1 Introduction - 261 M.2 Method A - 261 M.3 Method B - 265 M.3.1 Ringing signal - 265 M.3.2 Tripping device and monitoring voltage - 266 M.4 Other telecommunication signals - 268

Annex N (normative) Impulse test generators (see 2.10.3.4, 6.2.2.1 and G.5)

Annex P (normative) Normative references P.1 UL and CSA Component Requirements (mandatory) - 274 P.2 UL and CSA Component Requirements (alternative) - 278

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) .285 R.2 Reduced clearances (see 2.10.3) - 287

Annex S (informative) Procedure for impulse testing (see 6.2.2.3) S.1 Test equipment - 289 S.2 Test procedure - 289 S.3 Examples of waveforms during impulse testing - 289

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 - 294 U.2 Type tests - 294 U.2.1 Electric strength - 294 U.2.2 Flexibility and Adherence - 294 U.2.3 Heat shock - 295 U.2.4 Retention of electric strength after bending - 295 U.3 Test during manufacture - 296 U.3.1 Routine testing - 296 U.3.2 Sampling tests - 296

Annex V (normative) A.C. power distribution systems (see 1.6.1) V.1 Introduction - 297 V.2 TN power systems - 298 V.3 TT power systems - 301 V.4 IT power systems - 303

Annex W (informative) Summation of touch currents W.1 Touch current from electronic circuits - 305 W.1.1 Floating circuits - 305 W.1.2 Earthed circuits - 306 W.2 Interconnection of several equipments - 307 W.2.1 Isolation - 308 W.2.2 Common return, isolated from earth - 309 W.2.3 Common return, connected to protective earth - 309

Annex X (informative) Maximum heating effect in transformer tests (see C.1) X.1 Determination of maximum input current - 310 X.2 Overload test procedure - 311

Annex NAA (normative) Markings and instructions

Annex NAB (normative) Centralized d.c. power systems and special earthing requirements for d.c. powered equipment (see 3.6) NAB.1 System descriptions - 326 NAB.2 General requirements - 328 NAB.3 Special requirements - 329

Annex NAC (normative) Power line crosses (see 6.4) NAC.1 Equipment evaluation - 330 NAC.2 Test conditions - 331 NAC.3 Test set-up - 334 NAC.3.1 Equipment - 334 NAC.3.2 Wiring simulator - 335 NAC.3.3 Secondary protector simulator - 335 NAC.4 Compliance - 336

Annex NAD (informative) Terminology

Annex NAE (informative) U. S. and Canadian regulatory requirements INDEX (informative)