BS 7822-1:1995:2003 Edition
$198.66
Insulation coordination for equipment within low-voltage systems – Principles, requirements and tests
| Published By | Publication Date | Number of Pages |
| BSI | 2003 | 64 |
Specifies the requirements for clearances, creepage distances and solid insulation for equipment based upon their performance criteria.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | BRITISH STANDARD |
| 2 | Committees responsible for this British�Standard |
| 3 | Contents |
| 6 | Introduction |
| 7 | Section 1. General and definitions 1.1 Scope 1.1.1 This part of IEC 60664 deals with insulation coordination for equipment within low-voltage … 1.1.2 The object of this basic safety standard is to guide Technical Committees responsible for d… 1.2 Normative references |
| 8 | 1.3 Definitions 1.3.1 insulation coordination 1.3.2 clearance 1.3.3 creepage distance 1.3.4 solid insulation |
| 9 | 1.3.5 working voltage 1.3.6 recurring peak voltage 1.3.7 overvoltage 1.3.7.1 temporary overvoltage 1.3.7.2 transient overvoltage 1.3.7.3 functional overvoltage 1.3.8 Withstand voltages 1.3.8.1 impulse withstand voltage 1.3.8.2 r.m.s. withstand voltage 1.3.8.3 recurring peak withstand voltage 1.3.8.4 temporary withstand overvoltage |
| 10 | 1.3.9 rated voltage 1.3.9.1 rated insulation voltage 1.3.9.2 rated impulse voltage 1.3.9.3 rated recurring peak voltage 1.3.9.4 rated temporary overvoltage 1.3.10 overvoltage category 1.3.11 pollution 1.3.12 Environment 1.3.12.1 macro-environment 1.3.12.2 micro-environment 1.3.13 pollution degree 1.3.14 homogeneous field |
| 11 | 1.3.15 inhomogeneous field 1.3.16 controlled overvoltage condition 1.3.17 Insulations 1.3.17.1 functional insulation 1.3.17.2 basic insulation 1.3.17.3 supplementary insulation 1.3.17.4 double insulation 1.3.17.5 reinforced insulation 1.3.18 partial discharge (PD) 1.3.18.1 apparent charge 1.3.18.2 specified discharge magnitude 1.3.18.3 pulse repetition rate |
| 12 | 1.3.18.4 partial discharge inception voltage 1.3.18.5 partial discharge extinction voltage 1.3.18.6 partial discharge test voltage 1.3.19 Tests 1.3.19.1 type test 1.3.19.2 routine test 1.3.19.3 sampling test 1.3.20 electrical breakdown 1.3.20.1 sparkover 1.3.20.2 flashover 1.3.20.3 puncture |
| 13 | Section 2. Basis for insulation coordination 2.1 Basic principles 2.1.1 Insulation coordination with regard to voltage |
| 14 | 2.1.2 Insulation coordination with regard to environmental conditions 2.2 Voltages and voltage ratings 2.2.1 Determination of voltage for long-term stresses |
| 15 | 2.2.2 Determination of rated impulse voltage |
| 16 | Table 1 – Rated impulse voltage for equipment energized directly from the low-voltage mains |
| 17 | 2.2.3 Determination of recurring peak voltage Figure 3 – Recurring peak voltage 2.2.4 Determination of temporary overvoltage 2.3 Frequency 2.4 Time under voltage stress |
| 18 | 2.5 Pollution 2.5.1 Degrees of pollution in the micro-environment 2.5.2 Conditions of conductive pollution 2.6 Information supplied with the equipment 2.7 Insulating material 2.7.1 Comparative tracking index (CTI) |
| 19 | 2.7.2 Electric strength characteristics 2.7.3 Thermal characteristics 2.7.4 Mechanical and chemical characteristics |
| 21 | Section 3 – Requirements and dimensioning rules 3.1 Dimensioning of clearances 3.1.1 |
| 22 | Table 2 – Clearances to withstand transient overvoltages |
| 23 | Table 7 – Clearances to withstand steady-state voltages, temporary overvoltages or recurring peak voltages |
| 24 | 3.1.2 Electric field conditions 3.1.3 Altitude 3.1.4 Dimensioning of clearances of functional insulation 3.1.5 Dimensioning of clearances of basic, supplementary and reinforced insulation 3.1.6 |
| 25 | 3.2 Dimensioning of creepage distances 3.2.1 Influencing factors |
| 26 | 3.2.2 Dimensioning of creepage distances of functional insulation 3.2.3 Dimensioning of creepage distances of basic, supplementary and reinforced insulation Table 3a – Single-phase three or two-wire a.c. or d.c. systems |
| 27 | Table 3b – Three-phase four-or three-wire a.c. systems |
| 28 | Table 4 – Creepage distances to avoid failure due to tracking |
| 30 | 3.3 Requirements for design of solid Insulation 3.3.1 General 3.3.2 Stresses |
| 32 | 3.3.3 Requirements |
| 35 | Section 4. Tests and measurements 4.1 Tests 4.1.1 Test for verification of clearances |
| 36 | Table 5 – Test voltages for verifying clearances at sea level |
| 37 | Table 8 – Altitude correction factors |
| 39 | 4.1.2 Electric tests for solid insulation |
| 40 | Table 6 – Severities for conditioning of solid insulation |
| 42 | Figure 2 – Test voltages |
| 43 | 4.2 Measurement of creepage distances and clearances |
| 49 | Annex A (informative) Basic data on withstand characteristics of clearances Table A.1 – Withstand voltages in kilovolts for an altitude of 2 000 m above sea level |
| 50 | Table A.2 – Altitude correction factors |
| 51 | Figure A.1 – Withstand voltage at 2 000 m above sea level |
| 52 | Figure A.2 – Experimental data measured at approximately sea level and their low limits for inhomogeneous field |
| 53 | Figure A.3 – Experimental data measured at approximately sea level and their low limits for homogeneous field |
| 54 | Annex B (informative) Nominal voltages of supply systems for different modes of overvoltage control Table B.1 – Inherent control or equivalent protective control |
| 55 | Table B.2 – Cases where protective control is necessary and control is provided by surge arresters having a r… |
| 56 | Annex C (informative) Partial discharge test methods C.1 Test circuits C.1.1 Test circuit for earthed test specimen Figure C.1 – Earthed test specimen C.1.2 Test circuit for unearthed test specimen Figure C.2 – Unearthed test specimen C.1.3 Selection criteria |
| 57 | C.1.4 Measuring impedance C.1.5 Coupling capacitor C C.1.6 Filter C.2 Test parameters C.2.1 Requirements for the test voltage C.2.2 Climatic conditions C.3 Requirements for measuring Instruments C.3.1 General C.3.2 Classification of PD meters |
| 58 | C.3.3 Bandwidth of the test circuit C.4 Calibration C.4.1 Calibration of discharge magnitude before the noise level measurement C.4.2 Verification of the noise level C.4.3 Calibration for the PD test C.4.4 Calibration pulse generator |
| 59 | Figure C.3 – Calibration for earthed test specimen Figure C.4 – Calibration for unearthed test specimen Annex D (informative) Additional information on partial discharge test methods D.1 Measurement of PD inception and extinction voltage |
| 60 | D.2 Description of PD test circuits Figure D.1 – Partial discharge test circuits D.3 Precautions for reduction of noise D.3.1 General D.3.2 Sources of noise |
| 61 | D.3.4 Measures for reduction of noise D.4 Application of multiplying factors for test voltages D.4.1 Example 1 D.4.2 Example 2 |
| 62 | Annex E (informative) Comparison of creepage distances specified in Figure E.1 – Comparison of creepage distances specified in |
