Source: https://www.scribd.com/document/297056273/PCIC-2003-13
Timestamp: 2019-04-25 01:50:32+00:00

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product is attaining an increased focus.
designed in accordance with IEC standards.
switchgear construction and conformance test procedures.
(Euronorms) which use IEC 60439-1 as the template.
with enclosed, rather than open, switchgear assemblies”.
IEC 60439-1, on the other hand, is much broader in scope.
such as environmental protection and separation.
from the typical assembly verified to be in accordance with this standard (IEC 60439-1)”. 1600. the assembly voltage rating is subject to the relevant IEC standard associated with the devices contained within the assembly. separated by a 15 second interval of zero current) at rated maximum voltage”. IEC 60439-1 refers to 2 . For fused assemblies. Instruments. 800. B. there is introduced a degree of subjectivity pertaining to the phrase “without deviation likely to significantly influence the performance”.20. ANSI prescribes the switchgear assembly maximum primary voltage levels at 254. the power factor and peak values graduate with current while ANSI C37. RATINGS A. measuring. ANSI increases the power factor to 20% with a X/R ratio of 5.1 indicates that the manufacturer shall state the limits of voltage necessary for correct functioning of the main and auxiliary circuits. ANSI defines no such classification for tested assemblies. ANSI mandates minimum test duration of four cycles for the short-circuit current withstand test. the current shall flow until broken by the protective device.0 being the lower limit. no standard values can be given”. In the past. The duration of the test current for assemblies without incoming short-circuit protection shall not be less than three cycles if the short-circuit current withstand and short-time current withstand tests are conducted separately.6.20. As indicated by Table 1. 508 or 635 VAC.05 times operating voltage).5 1. IEC 60439-1 defines “type tested assembly” (TTA) and “partially type tested assembly” (PTTA) nomenclature to describe the classification of testing to which the equipment conforms. TABLE I IEC 60439-1 SHORT CIRCUIT TEST CONDITIONS RMS Value of ShortCircuit Current I ≤ 5kA 5 kA < I ≤ 10kA 10kA < I ≤ 20kA 20 kA < I ≤ 50kA 50 kA < I 3) Short Circuit Current Withstand: ANSI denotes this as a RMS current while IEC defines the rating as a peak current (peak withstand current). This rating as defined by ANSI includes allowance for operating above nominal system voltage. Bare bus and connections 3.1 2.20. or for assemblies which have been individually customized to suit specific needs.1 §4.0 2. For assemblies with incoming short-circuit protection. 2) Short-time Withstand Current: ANSI C37. IEC 60439-1 defines TTA as “a low-voltage switchgear and controlgear assembly conforming to an established type or system without deviations likely to significantly influence the performance. the important factor is that the vital characteristics of the type tested assembly remain intact and no deviation exist that would adversely impact the performance of the equipment. Voltage The voltage rating as defined by ANSI “is the highest rms voltage for which the equipment is designed. 3000.2 for continuous current ratings of 600. containing both type-tested and non type-tested arrangements provided that the latter are derived (e.” The compartmentalization of circuit breakers or “functional units” is contingent upon the form of separation declared by the manufacturer. 508 and 635 VAC.3 defines the rated short-time current as “the designated limit of available (prospective) current at which it shall be required to withstand its short-duty cycle (two periods of one-half second current flow. by calculation) from the type-tested arrangements which have complied with the relevant tests”. IEC 60439-1 speaks of test arrangements with and without a short-circuit protective device incorporated into the incoming unit. 70% 50% 30% 25% 20% Multiplying factor for minimum value of peak current 1.g. Test conditions for both IEC and ANSI are identical to their respective short-time current withstand tests. a peak current to be no less than 2. 1) Continuous Current: ANSI C37. 2000. The intent of the PTTA nomenclature is to address production type assemblies in which alterations are necessary.1 specifies a maximum power factor of 15%. III. Power Factor C.3 times the three phase rms symmetrical value and a minimum X/R ratio of 6. 4000 and 5000 amperes for Switchgear main bus.5 mm in diameter. IEC 60439-1 defines PTTA as “a low-voltage switchgear and controlgear assembly. Thus. meters.4. IEC ±25%) and test voltage (ANSI – 254. IEC 60439-1 specifies the duration of current flow to be 1 second unless otherwise stated by the manufacturer. ANSI Switchgear has frequently been applied at 50Hz. IEC – 1. and is the upper limit for operation”. 3200. IEC 60439-1 defines low-voltage switchgear and controlgear assemblies as “a combination of one or more lowvoltage switching devices together with associated control.4. As can be seen from the definition of “TTA”. protective. 1200. Within the definition. signaling. IEC 60439-1 §4. These voltage levels for the assembly are dictated by the ratings of the associated devices contained therein.2.1. Current Frequency ANSI indicates that the ratings for ac equipment are based on a frequency of 60 Hz. IEC 60439-1 states. “due to complex factors determining the rated currents.1 refers to §4. etc. Instrument and control power transformers 4. Control wiring and accessory devices It also requires that the circuit breakers be contained in individual grounded metal compartments. IEC requires an enclosure to have a minimum of an IP2X rating that provides protection against ingress of a solid object no greater than 12. regulating equipment. IEC 60439-1 makes no special considerations in test conditions for fused assemblies.7 2.2 Other subtle differences associated with test conditions include variations in test frequency (ANSI ±20%. and relays 5.
DESIGN TESTS Control Voltage ANSI C37. 1. IEC 60439-1 states that the verification of dielectric properties is performed by impulse withstand testing if the manufacturer declares a value. ANSI specifies a range for the dielectric test voltage frequency of ±20% while IEC dictates a range of 45 to 62Hz. Otherwise.the relevant IEC standards for the incorporated components and states that unless indicated by the manufacturer. A. meters and relays connected to circuits over 240 VAC so as to reduce the voltage on instrument wiring which must necessarily be closely grouped”. Each of these arrangements includes one circuit breaker in the uppermost cell intended for mounting.20.20. 508. Bottom compartment – 100% of compartment rating 2. Additionally.1 and IEC 60439-1 temperature rise limits is given in Appendix A. the following loading values are submitted. Preferred impulse withstand ratings are given in IEC 60439-1. ANSI C37. conventional (hypot) dielectric testing validates the dielectric integrity of main and control circuits. impulse withstand values are detailed in IEC 60439-1 for withdrawable devices in the isolated (disconnect) position. Cumulative Circuit Breaker Load and Rated Diversity Factor ANSI C37. Dielectric Tests IV. IEC 60439-1 prescribes no limits but requires the manufacturer to state the limits of voltage for control circuits. the circuit breaker is 3 . Top Compartment – 50% of compartment rating IEC 60439-1 refers to a rated diversity factor that is the ratio of the maximum sum of the assumed currents of the main circuits (main breakers or incoming units and branch circuits or outgoing units) to the sum of the rated currents of the main circuits. like ANSI.7 10 and above 0. E. Continuous Current TABLE II IEC DIVERSITY FACTORS Number of Main Circuits Diversity Factor 2 and 3 0. IEC diversity factors are as follows: TABLE III IEC 60439-1 INSULATION AND DIELECTRIC TEST VOLTAGES Rated Insulation Voltage (UI) Dielectric Test Voltage (AC rms) UI ≤ 60 1000 60<UI ≤300 2000 300<UI ≤690 2500 690<UI ≤800 3000 800<UI ≤1000 3500 2) Auxiliary and Control Circuits (when no impulse rating is declared for IEC equipment): ANSI C37. Annex G.8 6 to 9 inclusive 0. D.1 §4. The value of cumulative load can be based on equal loading (as a percentage of rating) of all cells or compartments within a vertical section or when equal loading is not practical.20.20. Only dielectric testing of main and control circuits is required by ANSI. the load distribution should be such that the heavier loads are connected to the lowest mounted circuit breaker.1 and G.1 submits several arrangements to be used for various continuous current ratings.1 reduces the test voltage level from neutral to ground to 1800V with IEC 60439-1 making no exception. ANSI references no such tests for low-voltage switchgear. 1) Main Circuits (When no Impulse Rating is Declared for IEC Equipment): The dielectric test value for ANSI assembly voltage ratings is 2200 VAC for one minute regardless of system voltage levels (254.1 states that “voltage and current transformers shall be used for all instruments. 3) Impulse Withstand: Although not required. IEC 60439-1 refers to IEC 60185 for CT ratings.1 submits preferred values for cumulative loading when multiple circuit breakers are housed in a single section.6 covers current transformer mechanical ratings. IEC 60439-1 varies the dielectric test voltage according to rated operational voltage of the equipment. the limits are assumed to be 98% and 102% of the rated frequency. Third Compartment – 60% of compartment rating 4. ANSI de-rates based upon the number of circuits and cell location in a given vertical section versus a quantity only basis by IEC. the methodology for deriving this factor is somewhat different for the two standards. Thus.20.9 4 and 5 0.20. F. ANSI C27. ANSI C37. For a vertical section with four cells.6 A comparison of ANSI C37. B.20. thermal ratings and minimum accuracy requirements for current transformers. Insulation and dielectric test voltages for IEC 60439-1 is tabulated below. In each case.1 does not require dielectric testing of control circuits as a design test but is required on production assemblies. IEC 60439-1 permits the use of these diversity factors when conducting continuous current tests. Table G.20. this diversity factor can be expressed for an assembly or. IEC 60439-1 references specified impulse withstand values to verify clearance and creepage distances in the event an impulse withstand voltage is declared by the manufacturer for main and control circuits. Current Transformer Ratings ANSI C27. 635 VAC).2 and offer a correlation between system operating voltage and impulse withstand voltage. IEC 60439-1 requires testing to voltage levels in accordance with Table III. part of an assembly (vertical sections with individual mounting compartments). ANSI does not address cumulative circuit breaker load on an assembly basis. Second Compartment – 75% of compartment rating 3. If no impulse withstand voltage ratings are declared by the manufacturer.1 conveys allowable cumulative load when all circuit breakers contained in the vertical section are of the same frame. According to IEC 60439-1.
Rain Test for Outdoor LV Switchgear ANSI C37. Furthermore. Like the through air clearances. Both standards dictate the limits for ambient temperature during testing must be between +10° C and +40° C for a valid test. These values are mandated by the UL 1558 standard.20.5 second. the minimum creepage distances specified by IEC 60439-1 are significantly lower than the generally accepted values corresponding to ANSI type equipment.00 inch (25. ANSI states that “the test arrangement shall be considered as having passed the test if there is no breakage of the bus supports and the equipment can withstand the dielectric requirements of ANSI C37. the minimum values are dependent upon the pollution degree and field conditions. the IEC 60439-1 requirements appear to be more stringent with regard to clearances and creepage distances along with post-test insulation integrity.1 dictates the measurement of ambient temperatures be taken 12.20. ANSI C37. However. IEC 60439-1 requires the use of a 0.50 (LV Power Circuit Breaker Conformance Testing Standards).20. The criteria for acceptable performance differ slightly. 4 Dielectric Withstand Tests (Main Circuits) .1 §5. IEC 60439-1 does not require mechanical endurance tests if devices have already been type tested according to their relevant specifications. G. H. Circuit breaker removable element position interlocks 4. E.20.4 mm) through air and 2. IEC 60439-1 does not address test requirements for outdoor equipment but refers to IEC 529 (“Degrees of Protection Provided by Enclosures”) for ingress protection ratings and states the second numeral to be at least three. C.2.loaded to the frame value.1 and C37.1 specifies no device for detecting fault current between the enclosure and ground. The IEC 60439-1 guidelines for creepage distances are given in Appendix C. ANSI C37. D. As with the phase bus testing. If impulse voltage withstand tests are performed. ANSI does not address the current value associated with neutral testing and is assumed to be the same value as tested during three phase testing. Mechanical Endurance ANSI C37. IEC 60439-1 states that the “value of the test current in the neutral bar shall be 60% of the phase current during the three-phase test”.2 must be complied with by manufacturers. Verification of Clearances and Creepage Distances IEC 60439-1 requires the verification of clearances and creepage distances by measurement.8 requires a paint qualification test of 200 hours salt-spray. Since pollution degrees 1 and 2 are not recommended for industrial applications. Separable primary contacts 2. ANSI C37.8mm diameter wire not less than 50 mm in length for detection of fault current.1 details the testing requirements for outdoor Switchgear enclosures. short-time current withstand testing is not required for the neutral conductor. only pollution degrees 3 and 4 are presented in Appendix C. Both standards require short-circuit withstand tests for the ground bus (protective conductor) at line to line voltage. a #10 AWG wire or 30 ampere fuse has been utilized for this purpose as a carryover from ANSI C37.20. ANSI C37. ANSI C37. In past ANSI qualification testing.51 require 100 mechanical operations for each frame of draw-out circuit breakers.00 inches (50.20.20. During the course of these tests.51 §4. For short-circuit withstand testing associated with a neutral conductor.1.4”. IEC 60439-1 makes no mention of paint qualification for low-voltage switchgear equipment. Stored-energy mechanism interlocks 5. IEC does not reference a short-time current test for the ground (protective conductor) bus. Differences in fault detection and acceptable performance results are identical to those stated above in the “Short-time Current Withstand” section above.20. the proper operation of the following elements is required: 1. Separable control contacts 3. V. Furthermore. However. F. ANSI mandates a 4-cycle duration while IEC 60439-1 permits the duration to be determined by the protective device. it states that the essential characteristics of the conductor insulation shall not degrade the mechanical and dielectric properties of the equipment. Although both standards require post withstand dielectric testing. Historically. IEC 60439-1 requires the ambient measurements be made 1 meter from the enclosure at approximately half its height. these numbers have been 1.1 requires the ground bus be capable of carrying the rated short-time current of the LV Switchgear for 0. Housing mounted breaker position switches (cell switch).1 does not dictate the through air or creepage distances. Paint Qualification ANSI C37. IEC 60439-1 states that the clearances and creepage distances specified in §7. As indicated by the data. Short Circuit Current Withstand Both IEC and ANSI require short-circuit current withstand testing.1 references no such rating scale for the environmental conditions in which the equipment operates. the minimum clearance dimensions in air are given in Appendix B. IEC does not submit arrangements for type testing. PRODUCTION (ROUTINE) TESTS A. operation of mechanical interlocks shall be verified after installation in the assembly by 50 mechanical operations.8 mm) over surface for 600V class Switchgear. In the event type testing has not been completed. In both standards. Short-time Current Withstand Both IEC and ANSI require short-time current withstand testing.00 inches from the enclosure at the following locations: (1) One level with the top of the structure (2) One 12 inches above the bottom of the structure and (3) One midway between the two positions indicated by (1) and (2).
5) Checking of Protective Measures and of the Electrical Continuity of the Protective Circuits: IEC 60439-1 requires that protective circuits be checked by inspection to ensure their continuity by effective interconnections either directly or by means of conductors.2. B. 4) Sequence Tests: Testing for proper sequencing of devices is required by ANSI while IEC states that depending upon the complexity of the assembly. Form 1 – No separation 2. IEC does not specify thickness of material for these barriers. sequence tests may need to be conducted to ensure proper operation. technical data. Ventilation openings are permitted provided that the gases produced by circuit breaker interruption shall not impair the operation of adjacent compartments. correctness of polarities is implied under control wiring continuity verification. are meant as the intent of the definition.20. Since ANSI offers no such varying degrees of separation. 5.1 either by impulse withstand (if manufacturer declares rating) or dielectric testing. For production tests. Form 3a – Separation of bus bars from the functional units and separation of all functional units but not of their terminals for external conductors. The terminals for external conductors need not be separated from the bus bars. IEC test values are based upon the rated insulation voltage as given in IV. However. ANSI requirements include a test voltage of 1500V for one minute or 1800V for one second.1 requires testing to verify “that connections between instrument transformers and meters or relays are correctly connected with proper polarities in accordance with circuit diagrams”. but not from each other. C. Form 4 – Separation of bus bars from the functional units and separation of all functional units from one another. or 3 mm) material.3. These measures are detailed in IEC 60439-1 §7. Separation of the terminals for external conductors from the functional units. Mechanical Operations ANSI specifies tests shall be performed to ensure the proper functioning of mechanical interlocks and interchangeability of removable elements designed to be interchangeable. 5. IEC 60439-1 requires the manufacturer’s name or trademark and type designation or identification number to appear on the equipment nameplate.1 of IEC 60439-1. IEC requires similar mechanical operation testing but does not address devices that are mechanically interchangeable.20. IEC defines this as “a part of an assembly comprising all the electrical and mechanical elements that contribute to the fulfillment of the same function”.ANSI C37. IEC requires similar tests per the guidelines discussed in section IV. the level of separation as defined by IEC for ANSI type equipment is Electrical Operation and Control Wiring Tests 1) Control Wiring Continuity: ANSI requires the correctness of control wiring be verified by either actual electrical operation of the devices or by conducting individual circuit continuity checks. when bus sectionalizing breakers are utilized (main or tie breakers).1196 in. 1. IEC 60439-1 makes no direct reference to verifying polarities of instrument transformers and meters or relays. Thus. 4. 4.20. VI. The following are typical forms of separation by barriers. the voltage is to be applied for one second. 2. This element represents one of the major differences between ANSI and IEC construction.A. along with its associated accessories and conductors. for IEC production or routine tests. the voltage is applied for one minute.A. etc. ANSI C37. B. including the terminals for external conductors which are an integral part of the functional unit. IEC states “the conformity of the assembly to the circuit and wiring diagrams. 3. 3) Polarity Verification: ANSI C37. 11 (nominal thickness of 0.1. Internal Barriers and Forms of Separation ANSI requires circuit breakers to be mounted in separate metal-enclosed compartments. 3. Form 3b – Separation of bus bars from the functional units and separation of all functional units from one another. In order to effectively comprehend the requirements of separation. barriers are required in the bus compartment to segregate the separate bus sections from each other. The metal barriers between compartments are required to be a minimum of MSG No. Form 2 – Separation of bus bars from the functional units. from one another. IEC addresses internal barriers to varying degrees. no barriers in the bus compartment are required. 2) Control Wiring Dielectric Test: Both standards require control wiring dielectric testing on production assemblies. Additionally. Recall for design tests. For branch circuits. Much commentary has been written regarding IEC forms of separation.1 requires the following minimum information on nameplates: 5 . Rather. one could deduce that the device. CONSTRUCTION FEATURES A.5 and should include random inspection of screw type terminals.4. A description of this information is given in §5. 1.1 requires low frequency withstand tests (2200V. The barriers defined by the “Forms of Separation” can be either metallic or non-metallic in construction. A host of other information including additional ratings and equipment description must appear either on the nameplate or in technical documentation if applicable. provided by the manufacturer shall be checked”. 1 minute) on each production assembly. the dielectric test voltage is only required for 1 second. it is important to understand the term “functional unit”. Manufacturer’s name and address Manufacturer’s type designation (optional) Manufacturer’s identification reference Rated maximum voltage Rated frequency Nameplates Both standards require equipment nameplates.
IEC 60439-1 submits guidelines for degrees of environmental conditions. In this case. E. Four earthing systems are defined in IEC 60364-4-41. by conductive dust by rain or snow.054)<S≤400 (.054) 16 (. for example.50 inch (12. IEC 60439-1 submits a set of preferred IP numbers where some protection against ingress of water is not required and mandates that the enclosure degree of protection of an enclosed assembly for indoor use to be at least IP2X and that the minimum IP between compartments be IP2X. C. The elements of the IP code are presented in Appendix D. However. ANSI C37. the IEC requirements are much more demanding with regard to conductor size. assemblies for indoor. Interchangeability of Removable Elements ANSI requires those removable elements of the same type and rating for a given assembly to be physically interchangeable. the manufacturer shall indicate the degree of protection of that part separately. non-conductive pollution occurs. F. TN-C as used in the USA and TN-S. the isolation of “functional units” becomes much more difficult due to the differences in construction.20. In comparing typical ampere ratings.7 mm) into an external opening unless the distance between the opening and the nearest live part is greater than 4 inches (101. however. d) Degree 4: The pollution generates persistent conductivity caused. the level of separation would have to be reduced to “Form 2” or possibly “Form 1” depending upon construction techniques. industrial applications are generally for use in a pollution degree 3 environment while outdoor. the neutral and ground are combined and the neutral does not need to be considered as a live bar. since 4-pole devices are not frequently used in ANSI type distribution Switchgear. Ground Bus (Protective Conductor) IEC 60439-1 specifies the cross sectional area of protective conductors according to the following table. the IP code for the standard ANSI construction would be IP10. one could argue that the standard ANSI construction coupled with additional insulation for circuit breaker connectors meets the requirements of “Form 3b” given by the written definition and the typical arrangements given in IEC 60439-1. on the operating face differs from that of the main portion. a temporary conductivity caused by condensation may be expected.62)<S≤800 (1.025) S 16 (. Test specifications and pass/fail criteria for each numeral or letter are given in IEC 60529. or dry. it is not mandated that secondary control circuits for these devices are electrically interchangeable. In the other three systems.62) S/2 400 (. for instance. D. IEC has extensive commentary regarding degrees of protection (references IEC 60529) and uses an “IP” (ingress protection) rating to classify the degrees. IEC does not address interchangeability. nonconductive pollution occurs which becomes conductive due to condensation. c) Degree 3: Conductive pollution occurs. b) Degree 2: Normally. the neutral shall have equivalent capacity. However. The letter “X” indicates that the characteristic need not be specified. Occasionally. a rod of diameter greater than 0. It has to be separated to the level required by the Form designation and have some means of isolation that often results in the use of 4-pole breakers. a) Degree 1: No pollution or only dry. Hence. industrial applications are for use in a pollution degree 4 environment. 2 If the phase conductor is less than 10 mm . TABLE IV IEC 60439-1 GROUND CONDUCTOR SIZE Cross Sectional Area of Phase Minimum Cross-sectional area of Conductors the Corresponding Protective S Conductor 2 2 Mm (in ) SP 2 2 mm (in ) S≤16 (. TT and IT systems. It should also be noted that if the degree of protection of part of the assembly. For comparison sake. particularly for bustie breakers. the neutral has to be considered to be live and must be treated as a phase conductor. a rod entry test is required to prevent the insertion of a rod of diameter 0. the conductors associated with “functional” units for 3 phase 4 wire applications are not packaged in close proximity due to the remotely mounted neutral conductors. the neutral conductor shall have half the current carrying capacity of the phase conductor with a 2 2 minimum of 10 mm if the phase conductor exceeds 10 mm . only non-conductive pollution occurs.025) 35 (.31) S>800 (1. ANSI does not specify the cross sectional area of ground conductors. Furthermore. Size of Neutral Conductor IEC 60439-1 states that unless agreed upon by the manufacturer and user. 2) Degrees of Protection: The ANSI requirements are that the enclosure design shall provide a degree of protection against limited amounts of falling dirt but will not prevent the entry of dust or liquids. The following definitions exist for degrees of pollution. IEC 60439-1 refers to IEC 60364-4-41 for earthing systems and requires that suitable earthing systems be indicated on the product labeling.025)<S≤35 (. Annex D.75 inch (19 mm) shall not be permitted to enter the opening. IEC indicates that unless otherwise stated. In TN-C systems. Enclosures 1) Environmental Classification: ANSI indicates that Low Voltage Switchgear shall be ventilated enclosures (NEMA Type 1) intended to provide a degree of protection against contact with the enclosed equipment.6 mm). the ground bus in ANSI low voltage Switchgear is sized to the NEC requirement of 12.24) S/4 6 . Therefore.1 does not address the capacity of neutral conductors.5 mm in diameter.5% of phase conductor cross section.difficult to apply. However. An IP2X rating provides protection against the ingress of a solid object no greater than 12. For 3-wire applications.24) 200 (.
the applicable particular requirements shall be complied with or special agreements shall be made between the user and manufacturer”. ANSI requires door interlocks on compartments in which current-limiting fuses are mounted in separate removable elements. one of the following protective measures must be used to guard against direct contact with live parts. tilting. there are many minor differences that were not discussed in this paper and it cannot be assumed that the two standards are in total agreement regarding these issues. opening or withdrawal must necessitate the use of a key or tool. VIII.1 restates the requirement for several interlocks.20. Unusual Service Conditions Although required by the ANSI power circuit breaker standard. G. IEC indicates the limits of temperature range to be -5°C to +40°C with the average over a period of 24 hours not exceeding +35°C. Prevention from closing the circuit breaker unless the primary disconnecting devices are in full contact or are separated by a safe distance. C37. Additionally. These differences along with the associated power system designs of each market. 3. it requires the wire to be a minimum of 14 AWG stranded with an insulation rating of 600V. oil vapors. In addition. Unifying the two standards would be difficult based upon the vast differences in product scope and market expectations throughout the world.2) Terminal Blocks: ANSI C37. ANSI does not address the issue of incidental contact when doors or covers are removed. Interlocks B. ANSI C37. Temperature and Humidity The range of ambient operating temperatures as declared by ANSI for indoor low-voltage Switchgear is -30°C to +40°C. This implies the usage of different insulation ratings is permissible in control circuits. IEC 60439-1 permits the use of soldered connections provided where provision is made for these type connections on the apparatus. APPLICATION CONDITIONS A. abnormal vibration. Operators shall be protected from the accidental discharge of the stored energy mechanism. IEC 60439-1 §6. 3.8. This interlock prevents door opening unless the associated breaker or switch is in the open position. 2.1. All live parts that can unintentionally be touched after the door has been opened shall be disconnected before the door can be opened.3 requires the use of type TBS or SIS wire for use between component devices or parts of Switchgear assemblies. for example 90% at +20°C. For circuit breakers with stored energy mechanisms. Higher relative humidities may be permitted at lower temperatures. 4.20. Removal. It does limit the size of removable covers for inspection and maintenance purposes to 2 12 ft or 60 pounds unless equipped with lifting means or hinges. 7 . In addition. H. shocks. They include: 1.1 §6. IEC prescribes limits for the relative humidity. Lower minimums of -25°C and -50°C are given for equipment designed for artic conditions.3.20. salt air.1 §7 provides the application guide for lowvoltage Switchgear. Doors and Covers IEC 60439-1 states that if it is necessary to make provision for removal of barriers. but does require that “withdrawable parts shall be fitted with a device which ensures that the apparatus can only be withdrawn after its main circuit has been interrupted”. An internal obstacle or shutter shielding all live parts shall exist which provides protection against unintentional contact when the door is open. seismic shock. Special service conditions are not addressed specifically by IEC 60439-1. Prevention from moving the circuit breaker to or from the connected position when the circuit breaker is in the closed position. For applications with vibrations. Unusual conditions such as exposure to hot and humid climates. IEC 604391 does not address wire size or type. VII. 1.2 states that “where special service conditions exists.20. I. the release of energy shall not be permitted unless the mechanism is fully charged. opening of enclosures or withdrawal of parts of enclosures. excessive dust. IEC 60439-1 does not address interlocks specifically. require that special consideration must be given when applying ANSI or IEC equipment in an application differing from the design standard to which the equipment conforms. IEC 60439-1 §7. In addition to the ambient temperature conditions. supplementary means for securing should be provided.1 dictates that external connections be suitable to accept AWG #10 and be of the solderless variety. Control and Secondary Wiring 1) Wire Type: ANSI C37. damaging fumes.1 states that the wiring shall be rated for at least the rated insulation voltage of the circuit concerned. It states that the “relative humidity does not exceed 50% at a maximum temperature of +40°C”. applications at high altitude and overload capabilities are addressed. CONCLUSIONS There are substantial differences in the testing procedures and construction techniques between ANSI and IEC lowvoltage switchgear. 2.
20.IX.2) 70 45 70 65 (3. 8 .1 Rise (ºC) unless otherwise noted IEC 60439-1 Rise (ºC) Subject to relevant standard for component Subject to relevant standard for component 30 65 30 (1. APPENDIX APPENDIX A COMPARISON OF TEMPERATURE RISE LIMITS. nature and surface treatment of the contact material • IEC 60439-1 offers no differentiation between plated and bare conductors. Total allowable temperature. tin surfaced or equivalent Air Temperatures Surrounding Cables Other parts or enclosure Metal parts subject to contact by operating personnel Insulating parts subject to contact by operating personnel External metal surfaces accessible to an operator in the normal course of duties External insulating surfaces accessible to an operator in the normal course of duties External metal surfaces not accessible to an operator in the normal course of duties External insulating surfaces not accessible to an operator in the normal course of duties (1) (2) (3) (4) (5) ANSI C37.2) (1. un-plated copper Connection to insulated cable silver surfaced. Not addressed by IEC 60439-1. TABLE A-1 Description Components Built-in Components Bus Bare Copper Bus Connection Plated Bus Connection Connection to insulated cables. Temperature limitation is based on use of 90° C cable in a 40° C ambient.5) (4) 50 (3) 15 50 (3) 25 70 (3) 30 70 (3) 40 110 (3) 40 Subject to temperature limits of insulating material 50 IEC 60439-1 does not specify values specifically for buses but offers the following as guidelines for determining the upper limit: Mechanical strength of conducting material • Possible effect on adjacent equipment • Permissible temperature limit of the insulating materials in contact with the conductor • The effect of the temperature of the conductor on the apparatus connected to it • For plug-in contacts.
25) 10.50 0.25) (.31) Pollution Degree Material Group II IIIa mm (in.0 (.00 14.20 0.0 (.0 (.39) 9 IIIb 4.22) 6.28) 8.) 5.01 0.04 0.00 8.00 14.79) 20.0 (.00 6.5 (.00 1.00 0.0 (.30 0.80 0.49) 16.00 3.50 4.00 5.60 2.00 2.60 3.0 6.20 1.14) 4.0 (.50 1.5 (.60 0.20 0.63) 20.20 5.80 1.50 2.01 0.0 (.31) 9.00 14.49) 12.0 10.6 (.63) 16.00 3.50 0.22) 6.0 I (.80 0.16) 4. APPENDIX C IEC 60439-1 CREEPAGE DISTANCES FOR EQUIPMENT.20 1.00 4.33 0.25) 7.0 (.31) (.0 (.79) .30 1.6 (.0 (.5 (.00 3.3 8.50 3.50 8.00 2.00 3.50 4.31) 10.00 3.50 4 1.2 5.0 6.50 2.04 0.0 (.49) 12.00 8.00 8.1 (.00 8.13) (.) 3.3 (.00 3.16) (.39) 12.20) (. TABLE A-III Rated Insulation Voltage I 250 400 500 630 3.10 0.0 (.10 0.00 14.3 8.50 Note: Case A clearances are required for Pollution Degrees 3 and 4.5 (.0 (.50 5.63) 16.25) 8.49) Pollution Degree Material Group II IIIa IIIb mm (in.6 (.00 4.0 (.16) 5.00 Minimum Clearances (mm) Case A Case B Pollution Degree Pollution Degree 2 3 4 1 2 3 0.50 4.35) 10.3 (.50 1.00 12. TABLE A-II Rated Impulse Withstand Voltage (kV) 1 0.APPENDIX B IEC 60439-1 MINIMUM CLEARANCES.50 1.39) (.39) 12.3 (.60 0.50 5.25) 6.
0 mm diameter Dust protected Dust-tight Against access to hazardous parts with Non-protected Back of hand Finger Tool Wire Wire Wire 0 1 2 3 4 5 6 7 8 Against ingress of water with harmful effects Non-protected Vertically dripping Dripping (15 degree tilted) Spraying Splashing Jetting Powerful jetting Temporary immersion Continuous immersion N/A N/A N/A N/A N/A N/A N/A N/A N/A Against access of solid foreign objects The access probe. IEC 60439-1. Against access to hazardous parts with Supplementary information specific to: High-voltage apparatus Moving parts in motion during water test Moving parts stationary during water test Weather conditions N/A N/A N/A N/A A B C D Supplementary Letter (Optional) H M S W 10 Back of hand Finger Tool Wire .0 mm diameter and 100 mm in length.5 mm diameter and 100 mm in length.5 mm diameter ≥ 1.APPENDIX D ELEMENTS OF THE IP CODE. An access probe of 2. shall have clearance from hazardous parts. TABLE A-IV Element Code Letters First Characteristic Numeral Second Characteristic Numeral Additional Letter (Optional) Numerals or Letters IP Meaning for the Protection of Equipment Meaning for the Protection of Persons 0 1 2 3 4 5 6 Against ingress of solid foreign objects Non-protected ≥50 mm diameter ≥ 12. shall have adequate clearance from hazardous parts. sphere of 50 mm diameter.5 mm diameter ≥ 2. shall have adequate clearance from hazardous parts. An access probe of 1. shall have adequate clearance from hazardous parts. A jointed test finger of 12 mm diameter and 80 mm in length.
XI. VITA Eddie Wilkie graduated from North Carolina State University in 1990 with a BSME. IEC 60529 (2001-02). IEEE Standard for MetalEnclosed AC Power Circuit Breaker Conformance Test Procedures. NY: IEEE. NY: IEEE. ACKNOWLEDGEMENTS The author gratefully acknowledges the contributions of Bob Yanniello and Richard Trussler who reviewed the paper several times during the course of its development. IEC 60947-1 (2001-12). Geneva.1-1993. Low-Voltage Switchgear and Controlgear Assemblies. He has been a design engineer and product development manager for Lowvoltage Switchgear assemblies. New York. REFERENCES      ANSI/IEEE C37. Switzerland: IEC. He has been employed by Cutler-Hammer since 1990. Geneva. IEEE Standard for MetalEnclosed Low-Voltage Power Circuit Breaker Switchgear.20. Degrees of Protection Provided by Enclosures (IP Code). Low-Voltage Switchgear and Controlgear – Part1: General Rules. XII. Switzerland: IEC. Switzerland: IEC. ANSI/IEEE C37. IEC 60439-1 (1999-09).51-1989. He is currently the engineering manager for Low-voltage switching devices. New York. Geneva. 11 .X.
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