BS 7626:1993

CHAPTER I: GENERAL REQUIREMENTS APPLICABLE TO ALL CURRENT
           TRANSFORMERS
SECTION ONE - GENERAL
1 Scope
2 Service conditions
3 Definitions
SECTION TWO - RATING AND PERFORMANCE REQUIREMENTS APPLICABLE
              TO ALL CURRENT TRANSFORMERS
4 Standard values of rated primary current
5 Standard values of rated secondary current
6 Rated continuous thermal current
7 Standard values of rated output
8 Short-time current ratings
9 Limits of temperature rise
10 Insulation requirements
SECTION THREE - TESTS - GENERAL
11 Classification of tests
SECTION FOUR - TYPE TESTS
12 Short-time current tests
13 Temperature-rise test
14 Impulse tests on primary windings
15 Wet test for outdoor type transformers
SECTION FIVE - ROUTINE TESTS
16 Verification of terminal markings
17 Power-frequency tests on primary windings and measurement
   of partial discharges
18 Power-frequency tests between sections of primary and
   secondary windings and on secondary windings
19 Test of interturn insulation
SECTION SIX - SPECIAL TESTS
20 Chopped lightning-impulse test on primary windings
21 Measurement of dielectric dissipation factor
SECTION SEVEN - MARKING
22 Terminal markings - General rules
23 Rating plate markings
CHAPTER II: ADDITIONAL REQUIREMENTS FOR MEASURING CURRENT
            TRANSFORMERS
SECTION EIGHT - GENERAL
24 Scope
25 Definitions
SECTION NINE - ACCURACY REQUIREMENTS
26 Accuracy class designation
27 Limits of current error and phase displacement
28 Extended current rating
SECTION TEN - TESTS FOR ACCURACY
29 Type tests
30 Routine tests
31 Instrument security current
SECTION ELEVEN - MARKING
32 Marking of the rating plate of a measuring current
   transformer
CHAPTER III: ADDITIONAL REQUIREMENTS FOR PROTECTIVE CURRENT
             TRANSFORMERS
SECTION TWELVE - GENERAL
33 Scope
34 Definitions
SECTION THIRTEEN - ACCURACY REQUIREMENTS
35 Standard accuracy limit factors
36 Accuracy classes
37 Limits of error
SECTION FOURTEEN - TESTS FOR ACCURACY
38 Type and routine tests for current error and phase
   displacement
39 Type tests for composite error
40 Routine tests for composite error
SECTION FIFTEEN - MARKING
41 Marking of the rating plate of a protective current
   transformer
APPENDIX A - Protective current transformers
Annex ZA (normative) Other international publications quoted
                       in this standard with the references of
                       the relevant European publications
Annex ZB (informative) B-Deviations
National annex NA (informative) Original IEC text amended by
                                CENELEC common modifications
National annex NB (informative) Cross-references

Applicable to newly manufactured current transformers for use with electrical measuring instruments and electrical protective devices at frequencies from 15 Hz to 100 Hz.