1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNovember 2, 20121UL 943COUTLINE OF INVESTIGATIONFORSPECIAL PURPOSE GROUND-FAULT CIRCUIT-INTERRUPTERSIssue Number 2November 2, 2012Summary of TopicsThis is the second issue of the Outline of Inves
2、tigation for SpecialPurpose Ground-Fault Circuit-Interrupters, Subject 943C, includingrevisions to the grounding monitor/interrupter, supervisory circuit, andmarking requirements, and including the addition of requirements forprogrammable circuit components and environmental sequence.COPYRIGHT 2012
3、UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 2, 2012UL 943C2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUC
4、TION1 Scope .42 Glossary .63 Components 64 Units of Measurement .75 Undated References 7CONSTRUCTION6 General 77 Grounding Circuit .78 Spacings .89 Grounding Monitor/Interrupter 910 Insulation .911 Supervisory Circuit .912 Programmable Circuit Components .10PERFORMANCE13 General 1114 Environmental T
5、est Sequence 1115 High Resistance Ground-Fault Test .1316 Grounded Neutral Test 1417 Resistance to False Tripping Test 1418 Grounding Monitor/Interrupter Test 1419 Overload and Motor Starting .1620 Low Resistance Ground Fault 1621 Endurance Test 1622 Surge Current Test .1823 Abnormal Overvoltage Tes
6、t 1824 Extra Low Resistance Ground Fault Test 1925 Short Circuit Test .19MARKINGS26 General 2027 Class Marking 2028 Other Markings .2029 Instructions 21APPENDIX A Sample Calculation of Grounding Conductor SizeA1 Sample Calculation of Grounding Conductor Size A1NOVEMBER 2, 2012 UL 943C 3UL COPYRIGHTE
7、D MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover ground-fault circuit-interrupters intended for use in one of the followingapplications:a) Where the voltage to ground is greater than 150 volts and equipment gr
8、ounding or doubleinsulation is required by the National Electrical Code, ANSI/NFPA 70,b) Where the voltage to ground is 150 volts or less and equipment grounding or double-insulation is provided, but the use of a Class A ground-fault circuit-interrupter is not practical.1.2 Ground-fault circuit-inte
9、rrupters addressed by these requirements are divided into three classes,Class C, D and E, based upon voltage rating and the characteristics of the grounding circuit. Some areintended for use in circuits where grounding is not provided to the load but double-insulation is provided.1.3 These ground-fa
10、ult circuit-interrupters are intended to be applied on circuits as shown in Figure 1.1.The requirements for Class A ground-fault circuit-interrupters are in the Standard for Ground-FaultCircuit-Interrupters, UL 943.This is generated text for figtxt.NOVEMBER 2, 2012UL 943C4UL COPYRIGHTED MATERIAL NOT
11、 AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULFigure 1.1Application of GFCIsNOVEMBER 2, 2012 UL 943C 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL2 Glossary2.1 For the purposes of this Outline of Investigati
12、on, the following definitions apply. Additional definitionsare in the Glossary of the Standard for Ground-Fault Circuit-Interrupters, UL 943.2.2 CLASS C GROUND-FAULT CIRCUIT-INTERRUPTER A ground-fault circuit-interrupter that isintended to be used in circuits with no conductor over 300 V AC to groun
13、d where reliable equipmentgrounding or double insulation is provided.2.3 CLASS D GROUND-FAULT CIRCUIT-INTERRUPTER A ground-fault circuit-interrupter that isintended to be used in circuits with one or more conductors over 300 volts to ground, and with speciallysized, reliable grounding, to provide a
14、low impedance path so that the voltage across the body during afault does not exceed 150 volts.2.4 CLASS E GROUND-FAULT CIRCUIT-INTERRUPTER A ground-fault circuit-interrupter that isintended to be used in circuits with one or more conductors over 300 volts to ground but withconventional equipment gr
15、ounding provided for the protected equipment in the system or doubleinsulation. These ground-fault circuit-interrupters respond rapidly to open the circuit before themagnitude and duration of the current flowing through the persons body exceeds the limits forventricular fibrillation.2.5 GROUNDING MO
16、NITOR/INTERRUPTER A device that monitors equipment grounding continuityin a protected system. It prevents the circuit from being energized under conditions where the groundingis not available and causes the circuit to be interrupted where the grounding is lost during operation.2.6 SPECIALLY SIZED GR
17、OUND A grounding conductor whose size is based on a ratio withrespect to the size of the ungrounded conductor in order to limit the voltage to which a person would beexposed in the event of a fault to ground.3 Components3.1 Except as indicated in 3.2, a component of a product covered by this Outline
18、 of Investigation shallcomply with the requirements for that component.3.2 A component need not comply with a specific requirement that:a) Involves a feature or characteristic not needed in the application of the component in theproduct covered by this Outline of Investigation, orb) Is superseded by
19、 a requirement in this Outline of Investigation.3.3 A component shall be used in accordance with its recognized rating established for the intendedconditions of use.3.4 Specific components are recognized as being incomplete in construction features or restricted inperformance capabilities. Such comp
20、onents are intended for use only under limited conditions, such ascertain temperatures not exceeding specified limits, and shall be used only under those specific conditionsfor which they have been recognized.NOVEMBER 2, 2012UL 943C6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORD
21、ISTRIBUTION WITHOUT PERMISSION FROM UL4 Units of Measurement4.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.5 Undated References5.1 Any undated reference to a code or standard appearing in the requirements of this Outline ofI
22、nvestigation shall be interpreted as referring to the latest edition of that code or standard.CONSTRUCTION6 General6.1 The products covered by this Outline shall comply with the construction requirements of the Standardfor Ground-Fault Circuit-Interrupters, UL 943, except as modified by these requir
23、ements.7 Grounding Circuit7.1 Except as noted in 7.2, the grounding circuit of the circuit in which these ground-faultcircuit-interrupters are used shall be continuous, of low resistance, and reliable.7.2 Equipment grounding is not required in the circuit to the load if the load is double insulated.
24、 See 10.2.7.3 The grounding circuit of the circuit in which a Class D ground fault circuit-interrupter is used shall beof sufficiently low impedance that, should a fault to ground occur, the voltage resulting across thegrounding circuit shall not exceed 150 volts. The size of the grounding conductor
25、 required for a circuit shallbe determined by calculating the resistance using the following formula and converting that value to a wiregauge based on the length of the grounding conductor.RG= (150RU)/(Vl-g- 150)Where:RG= the resistance of the grounding conductor,RU= the resistance of the ungrounded
26、 conductor, andVl-g= the supply line to ground voltage in RMS V AC.Refer to Appendix A for a sample calculation of grounding conductor size.NOVEMBER 2, 2012 UL 943C 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL8 Spacings8.1 Except as indic
27、ated in 8.2 8.5, the spacing requirements of the Standard for Ground-FaultCircuit-Interrupters, UL 943 shall apply for all locations.8.2 The spacing requirements of the Standard for Ground-Fault Circuit-Interrupters, UL 943 for potentialsof 201-400 V peak shall also apply to locations with a potenti
28、al up to 425 V peak.8.3 Except as indicated in 8.4, the spacings for potentials of 426 through 850 V peak at locations otherthan field wiring terminals shall be per Table 8.18.4 The minimum allowable spacing from any live part to a metal enclosure where the potential is 426through 850 volts peak is
29、25.4 mm (1 inch).Table 8.1Minimum spacings at other than field wiring terminalsOperating potential between parts426 850 V peakSpacings in mm (inches)Through air Over surfaceOpenaClosed-inbOpenaClosed-inb9.5 (3/8) 6.4 (1/4) 12.7 (1/2) 6.4 (1/4)aA space that is not specially protected from deposition
30、of dirt.bA space that is specially protected from deposition of dirt; that is, a sealed housing that meets the requirements of the dusttest of the Standard for Ground-Fault Circuit-Interrupters, UL 943.8.5 The spacing for potentials of 426 through 850 V peak at field wiring terminals shall be per Ta
31、ble 8.2.Table 8.2Minimum spacings at field wiring terminalsOperating potential between parts426 850 V peakSpacings in mm (inches)Through air Over surface12.7 (1/2) 12.7 (1/2)NOVEMBER 2, 2012UL 943C8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM
32、 UL9 Grounding Monitor/Interrupter9.1 Except as indicated in 9.2 and 9.3, a device to monitor the equipment grounding continuity betweenthe supply and the protective device and between the protective device and the load shall be provided.This device shall prevent the circuit from becoming energized
33、under conditions where the grounding is notavailable and shall interrupt the circuit under conditions where grounding is lost during operation.9.2 A grounding monitor/interrupter shall not be required to monitor the equipment ground between thesupply and the protective device when the protective dev
34、ice is permanently connected to the supply.9.3 A grounding monitor/interrupter shall not be required to monitor the equipment ground to the loadwhen the load employs a system of double insulation.9.4 To demonstrate that a grounding monitor/interrupter meets the requirements of 9.1 - 9.3, tests asdes
35、cribed in Section 18 shall be performed as applicable.10 Insulation10.1 Functional insulation shall be provided throughout a ground-fault circuit-interrupter.10.2 Double insulation, when provided, shall comply with the requirements of the Standard for DoubleInsulation Systems for Use in Electrical E
36、quipment, UL 1097, or the Reference Standard for DoubleInsulation Systems for Use in Electronic Equipment, UL 2097, as applicable.11 Supervisory Circuit11.1 Except as indicated in 11.2 and 11.3, the supervisory circuit shall comply with Section 5.15 of theStandard for Ground-Fault Circuit-Interrupte
37、rs, UL 943.11.2 The current employed by the supervisory circuit shall be sufficient to cause tripping at 85 percent ofrated voltage, provided that at rated voltage the current does not exceed 30 mA.11.3 The supervisory circuit of a device intended for use on a three phase circuit shall be permitted
38、torely on the equipment grounding conductor to operate.NOVEMBER 2, 2012 UL 943C 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL12 Programmable Circuit Components12.1 If a device employs a programmable circuit component such as a microprocess
39、or in its ground faultdetection or interruption system, that portion of the device shall be investigated in accordance with theStandard for Software in Programmable Components, UL 1998, as defined in 12.2 12.9.12.2 All of the requirements of the Standard for Software in Programmable Components, UL 1
40、998, applyto microprocessors employed in a device as mentioned in 12.1, except as modified by 12.3 12.9.12.3 The risks to be considered for the Risk Analysis portion of UL 1998 include the following scenarios:a) Unwanted tripping;b) Failure to trip under conditions where tripping should occur;c) Tri
41、pping at the wrong trip threshold value; andd) Failure of test circuit to complete evaluation.12.4 The Tool Qualification requirements from UL 1998 are modified in 12.5 and 12.6.12.5 All tools used in the design, implementation, and verification of software shall be documented. Thedocumentation shal
42、l include:a) The name of the tool supplier or developer;b) The model, application, or trade name of the tool;c) The tool version identification;d) A description of the purpose for which the tool is used; ande) A list of known errors, faults or failures of the tool performance, such as a bug list.12.
43、6 Software tools are defined as software or hardware used in the development, testing, analysis, ormaintenance of a program or its documentation. Examples include compilers, assemblers, timinganalyzers, logic analyzers, test case generators, simulators, emulators, and similar tools.12.7 Means shall
44、be employed to address all microelectronic hardware failure modes identified in the RiskAnalysis of 12.3. The analysis shall consider all possible combinations of microelectronic hardwarefailures, software faults, and other events that are capable of resulting in a risk. This includes, for example,m
45、icroelectronic hardware failures that cause software faults that are capable of resulting in a risk.Detection of failure modes shall be at a frequency and adequacy suitable for the application.12.8 One approach to comply with 12.7 is for the manufacturer to:a) Identify failure modes;b) Determine saf
46、ety impact of failure modes;c) Design and provide means to detect the failure modes that have an impact on safety;NOVEMBER 2, 2012UL 943C10UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULd) Demonstrate that coverage provided by detection means
47、 is at a frequency and effective levelsuitable for the application; ande) Provide evidence that the failure rate of microelectronic components is suitable for theapplication.12.9 The requirements in UL 1998 addressing user interfaces do not apply.PERFORMANCE13 General13.1 Products covered by this Ou
48、tline shall comply with the performance requirements of the Standardfor Ground-Fault Circuit-Interrupters, UL 943, except as modified by these requirements.14 Environmental Test Sequence14.1 A device that has been subjected to the applicable conditioning tests of Sections 6.4 - 6.6 of theStandard fo
49、r Ground-Fault Circuit-Interrupters, UL 943, shall comply with the applicable tests in Sections14, 15, 16, and 18 of this Outline, while operating in ambient air at 25C (77F). Except as indicated in14.2- 14.9, the device shall also comply when tested in ambient air at 66C (150.8F), -35C (-31F), and25C (77F) by following the sequence of steps shown in Table 14.1. The ambient air temperature is tobe changed to each value without intentional delay.14.2 When conducting the test of Step 3 of Table 14.1 at 66C, in the event a device is self-protectingsu
