SA FETY REQUIREMENTS FOR ELECTRICAL EQUIPMENT Part 031: Safety requirements for hand-held probe assembl es f or electrical measurement and test 1 Scope and object 1.1 Scope 1.1.1 Probe a
Parts and accessories 1 4
TERMIN AL component provided for the connection of a device (equipment) to external conductors
Note 1 to entry: T ERMI NALS can contain one or several contacts and the term includes sockets, pins, connectors, etc
ENCLOSURE part providing protection of a probe assembly against certain external influences and, in any direction, protection against direct contact
PROTECTIVE FINGERGU ARD part of the ENCLOSURE that indicates the limit of safe access and that reduces the risk of the
OPERATOR touching HAZARDOUS LIVE parts
PROBE TIP part of a probe assembly or accessorywhich makes a connection to the point being measured or tested
Note 1 to entry: The term “ PROBE TI P ” includes the conductive parts of the jaws or hooks of SPRI N G - LOADED CLI PS
CONNECTOR component which is attached to the PROBE WIRE, to connect to a TERMINAL of the equipment or to a CONNECTOR of another probe assembly
TOOLexternal device, including a key or coin, used to aid a person performing a mechanical function
PROBE WIRE flexible wire or cable used as part of the probe assembly or its accessories, consisting of one or more conductors and associated insulation
SPRING-LOADED CLIP probe or probe accessory with one or more hooks or jaws forced by a spring to grip the part being measured or tested
CONNECTOR assembly which contains an additional TERMINAL
EXAMPLE: Figure 5 is an example of a STACKABLE CONN ECTOR with a male CON NECTOR and a female TERMI N AL
1 T ERM I N AL for additional CONN ECTOR
Figure 5 – Example of a STACKABLE CONNECTOR with a male CONNECTOR and a female TERMINAL
Quantities 1 5
RATED (condition or value) condition or quantity value assigned, generally by a manufacturer, for a specified operating condition of a component, device, or probe assembly
RATING set of RATED values and operating conditions
WORKING VOLTAGE highest r.m.s value of the a.c or d.c voltage across any particular insulation which can continuously appear during NORMAL USE
Note 1 to entry: Transients and voltage fluctuations are not considered to be part of the WORKI N G VOLTAGE
Tests 1 6
A TYPE TEST evaluates one or more samples of a probe assembly or its components, ensuring that the design and construction comply with the specified standards.
Note 1 to entry: This is an amplification of the IEC 60050-1 51 : 2001 , 1 51 -1 6-1 6 definition to cover design as well as construction
ROUTINE TEST conformity test made on each individual item during or after manufacture
Safety terms 1 6
ACCESSIBLE able to be touched with a standard test finger or test pin, when used as specified in 6.2
HAZARDOUS LIVE capable of rendering an electric shock or electric burn
HAZARD potential source of harm
PROTECTIVE IMPEDANCE component or assembly of components whose impedance, construction and reliability are suitable to provide protection against electric shock
NORM AL USE operation, including stand-by, according to the instructions for use or for the obvious intended purpose
NORM AL CONDITION condition in which all means for protection against HAZARDS are intact
SINGLE FAULT CONDITION condition in which one means for protection against a HAZARD is defective or one fault is present which could cause a HAZARD
OPERATOR person operating the probe assembly for its intended purpose
RESPONSIBLE BODY individual or group responsible for the safe use and maintenance of probe assemblies
A wet location is defined as an area where water or another conductive liquid may be present, potentially reducing the human body's impedance This occurs due to the wetting of the contact between the human body and the probe assembly, or between the human body and the surrounding environment.
MEASUREMENT CATEGORY classification of testing and measuring circuits according to the types of mains circuits to which they are intended to be connected
REASON ABLY FORESEEABLE MISUSE use of a product in a way not intended by the supplier, but which may result from readily predictable human behaviour
Insulation 1 7
BASIC INSULATION insulation of HAZARDOUS LIVE parts which provides basic protection
SUPPLEMENTARY INSULATION independent insulation applied in addition to BASIC INSULATION in order to provide protection against electric shock in the event of a failure of BASIC INSULATION
DOUBLE INSULATION insulation comprising both BASIC INSULATION and SUPPLEMENTARY INSULATION
REINFORCED INSULATION insulation which provides a degree of protection against electric shock not less than that provided by DOUBLE INSULATION
POLLUTION addition of foreign matter, solid, liquid or gaseous (ionized gases), that may produce a reduction of dielectric strength or surface resistivity
POLLUTION DEGREE numeral indicating the level of POLLUTION that may be present in the environment
POLLUTION DEGREE 1 no POLLUTION or only dry, non-conductive POLLUTION occurs, which has no influence
POLLUTION DEGREE 2 only non-conductive POLLUTION occurs except that occasionally a temporary conductivity caused by condensation is expected
POLLUTION DEGREE 3 conductive POLLUTION occurs, or dry, non-conductive POLLUTION occurs which becomes conductive due to condensation which is expected
CLEARANCE shortest distance in air between two conductive parts
CREEPAGE DISTANCE shortest distance along the surface of a solid insulating material between two conductive parts
SPACING any combination of CLEARANCES and CREEPAGE DISTANCES
General 1 8
The standard mandates TYPE TESTS on samples of probe assemblies or their components to verify that their design and construction comply with the specified requirements Additionally, ROUTINE TESTS outlined in Annex D must be conducted on the PROBE WIRE.
The probe assembly must meet the minimum requirements outlined in this standard, with the option to exceed them If a lower limit is set for a conformity value, the assembly can show a higher value, while a specified upper limit allows for a lower value It is essential to consider manufacturing variations and tolerances.
Components of the probe assembly that comply with the relevant standards do not require retesting during the TYPE TESTS of the entire assembly, provided they are used according to those standards.
If a probe assembly is of more than one probe type (see 1 1 1 ), each type shall be tested according to its applicable requirements
Compliance with this standard is verified through the execution of all relevant tests, although a test may be excluded if a thorough review of the probe assembly and design documentation confirms it would pass Testing is conducted under both reference test conditions and fault conditions.
Conformity statements in this standard necessitate inspection, which may involve measuring the probe assembly, reviewing its markings, assessing the accompanying instructions, and examining the data sheets of the materials or components used in its manufacture.
In each case, the inspection will either demonstrate that the probe assembly meets the applicable requirements, or will indicate that further testing is required
During conformity testing, if there is uncertainty regarding the exact value of an applied or measured quantity, such as voltage, manufacturers must ensure that the specified test value is met or exceeded, while test houses must ensure that the applied value does not exceed the specified limit.
Manufacturers must ensure that probe assemblies meet safety requirements even if their rated range of environmental conditions exceeds the specifications outlined in section 1.4.1 This can be achieved through appropriate modifications to testing requirements or by conducting additional tests.
Probe assemblies that have undergone type testing may become unsuitable for their intended function due to residual stress effects from the tests Therefore, any probe assembly that has been type tested should not be put into use.
Sequence of tests 1 9
The sequence of tests is optional unless stated otherwise, and probe assemblies must be thoroughly inspected after each test If any test result raises concerns about the validity of previous tests had the order been reversed, those earlier tests must be repeated.
Testing in SINGLE FAULT CONDITION
General
The examination of the probe assembly and its circuit diagram is essential to identify potential hazards Fault tests must be conducted as specified to ensure conformity, unless it can be proven that a specific fault condition poses no hazard Additionally, the probe assembly should be tested under the least favorable reference conditions, which may vary for different faults and must be documented for each test.
Application of fault conditions
Fault conditions must adhere to the specifications outlined in sections 4.4.2.2 to 4.4.2.5 Each fault should be applied individually and in a convenient sequence Simultaneous multiple faults are not permitted unless they result from an applied fault.
After each application of a fault condition, the probe assembly or part shall pass the applicable tests of 4.4.4
When a PROTECTIVE IMPEDANCE is created using multiple components, each component must be either short-circuited or disconnected, depending on which option is less favorable However, if the PROTECTIVE IMPEDANCE is established with a single component that complies with the requirements of section 6.4.5, it does not need to be short-circuited or disconnected.
4.4.2.3 Probe assemblies or parts for short-term or intermittent operation
These shall be operated continuously if continuous operation could occur in a SINGLE FAULT CONDITION
Outputs of Type B and Type C probe assemblies shall be short-circuited
4.4.2.5 Insulation between circuits and parts
Insulation that falls below the standards for BASIC INSULATION must be bridged to prevent fire spread when employing the method outlined in section 9.1.
Duration of tests
The probe assembly will continue to operate until it is unlikely that further changes will occur due to the applied fault Each test is typically restricted to one hour, as a secondary fault resulting from a single fault condition usually appears within this timeframe If any indications arise, they will be addressed accordingly.
HAZARD of electric shock, spread of fire or injury to persons may eventually occur, the test shall be continued for a maximum period of 4 h.
Conformity after application of fault conditions
To ensure compliance with electric shock protection requirements after single faults, it is essential to conduct specific checks First, measurements outlined in section 6.3.3 must be performed to verify that no accessible conductive parts have become hazardous live, except as allowed by section 6.1 Additionally, a voltage test should be conducted on double insulation or reinforced insulation to confirm that the protection level remains at least equivalent to basic insulation These voltage tests are to be carried out as specified in section 6.6, without humidity preconditioning, using the test voltage for basic insulation.
Conformity with requirements for temperature protection is checked by determining the temperature of the outer surface of the probe assembly (see Clause 9)
This temperature is determined by measuring the temperature rise of the surface or part and adding it to the maximum RATED ambient temperature
To ensure compliance with fire protection requirements, the probe assembly must be placed on white tissue paper over a softwood surface and covered with cheesecloth It is essential that no molten metal, burning insulation, or flaming particles come into contact with the surface beneath the probe assembly Additionally, there should be no charring, glowing, or flaming of the tissue paper or cheesecloth Melting of insulation material is permissible as long as it does not pose any hazard.
Conformity with the requirements for protection against other HAZARDS is checked as specified in Clauses 7 to 13.
Tests in REASONABLY FORESEEABLE MISUSE
General
Tests needed to support a risk assessment pertaining to REASONABLY FORESEEABLE MISUSE are carried out in the combinations of conditions and operations determined during the risk assessment.
Fuses
Fused probe assemblies are essential for ensuring safety in situations where the connected equipment may not offer adequate protection, especially under reasonably foreseeable misuse conditions that could result in fire or arc explosions.
This test assumes that the equipment connected to the probe assemblies behaves like a short circuit and that the fused probe assembly can be linked to any voltage source within its rating Consequently, any current level up to the maximum prospective short circuit current can be applied For mains installations, the fuse must be rated according to section 12.2, eliminating the need for additional testing related to the interrupt current rating However, it is essential to conduct tests at current levels close to the fuse rating to prevent excessive temperature rise in handheld components and to avoid damage to insulating parts, enclosures, and barriers.
The maximum fuse temperature, even under current loads up to five times the fuse rating, does not pose a hazard when assessed through the fused probe assembly Compliance is verified through thorough inspection and measurement.
Marking
Probe assemblies must be marked according to sections 5.1.2 to 5.2 Any markings that pertain to the entire probe assembly should not be placed on components that can be removed by an operator without the use of tools.
Letter symbols for quantities and units must adhere to IEC 60027 standards, while graphic symbols should follow the guidelines outlined in Table 1, if relevant There are no specific requirements regarding size or color In cases where a symbol is not listed in Table 1, any alternative graphic symbol can be utilized on a probe assembly, provided that it is clearly explained in the accompanying documentation (refer to section 5.4.1).
If all required markings cannot be applied to the part, essential information must be documented Additionally, Symbol 7 from Table 1 may be utilized.
Conformity is checked by inspection
Each probe assembly, along with its accessories when applicable, must be clearly labeled with the manufacturer's or supplier's name or registered trademark Additionally, for Type B and Type C probes, it is essential to include the model number, name, or another identifying means for the probe assembly or its components.
Probe assemblies intended for use with a specific equipment model must clearly indicate this limitation Identification of the specific equipment or model should be provided through markings on the probe assembly or detailed in the accompanying documentation.
Conformity is checked by inspection
3 IEC 6041 7-5033 (2002-1 0) Both direct and alternating current
4 IEC 6041 7-501 7 (2006-08) Earth (ground) TERM I NAL
5 IEC 6041 7-6042 (201 0-1 1 ) Caution, possibility of electric shock
7 ISO 7000-0434 (2004-01 ) Caution a a See 5.4.1 which requires manufacturers to state that documentation must be consulted in all cases where this symbol is marked
Probe assemblies designed for operator-replaceable fuses must be clearly marked with essential details to ensure the correct fuse is obtained This includes the voltage rating and breaking capacity, which indicates the maximum current the fuse can safely interrupt at the highest rated voltage If space is limited, Symbol 7 from Table 1 should be marked on the probe assembly, with the necessary information provided in the accompanying documentation.
Conformity is checked by inspection
If necessary for safety, an indication shall be given of the purpose of CONNECTORS, TERMI NALS, and controls, including any sequence of operations
Conformity is checked by inspection
Probe assemblies must be clearly marked with their RATING Assemblies without a RATING for MEASUREMENT CATEGORIES II, III, or IV should display the RATED voltage to earth along with Symbol 7 from Table 1 In contrast, probe assemblies designed for MEASUREMENT CATEGORIES II, III, and IV must indicate both the RATED voltages to earth and the corresponding MEASUREMENT CATEGORY markings, which should be labeled as "CAT II," "CAT III," or "CAT IV" as appropriate.
Markings on a probe assembly should ideally be located on the probe body, indicating the type of voltage (a.c., d.c., etc.), unless the marking is applicable to both a.c r.m.s and d.c If a reference connector is designed for connections at voltage levels exceeding those specified in section 6.3.2, the rated voltage must be clearly marked on the connector or as near to it as possible.
For Type A and Type D probe assemblies, it is essential to mark the RATED current alongside the RATED voltage to earth However, probe assemblies designed exclusively for use with equipment featuring high-impedance inputs or limited-current outputs do not require the RATED current to be marked.
Conformity is checked by inspection.
Warning markings
Warning markings shall be legible when the probe assembly is ready for NORMAL USE
To maintain the protection provided by the probe assembly, the OPERATOR must consult the instruction manual, which will be indicated by the Symbol 7 from Table 1 If a warning pertains to a specific component of the probe assembly, the corresponding marking will be located on or near that component.
When instructions permit an OPERATOR to access potentially HAZARDOUS LIVE parts using a TOOL, a warning must indicate that the probe assembly should be isolated or disconnected from the HAZARDOUS LIVE voltage prior to access Alternatively, Symbol 7 from Table 1 can be utilized, provided that this information is included in the instructions for use.
Parts that can be easily touched and may exceed the temperature limits specified in section 9.1 must be marked with Symbol 6 from Table 1, unless their heated state is clearly visible or evident from the probe assembly's function.
Conformity is checked by inspection.
Durability of markings
Required markings shall remain clear and legible under conditions of NORMAL USE and shall resist the effects of cleaning agents specified by the manufacturer
Conformity is checked by performing the following test for durability of markings on the outside of the probe assembly The markings are rubbed by hand, without undue pressure, for
30 s with a cloth soaked with each specified cleaning agent, one at a time, or, if not specified, with a solution containing a minimum of 70 % isopropyl alcohol in water
After the above treatment the markings shall be clearly legible and adhesive labels shall not have worked loose or become curled at the edges.
Documentation
General
Probe assemblies must include essential documentation for safety, which should consist of the technical specification, usage instructions, the manufacturer's or supplier's contact information for technical support, and the details outlined in sections 5.4.2 to 5.4.4.
Warning statements and clear explanations of warning symbols on the probe assembly must be included in the documentation or marked durably and legibly on the assembly itself Specifically, it is essential to consult the documentation whenever Symbol 7 from Table 1 is referenced to understand the nature of the potential hazard and the necessary actions to be taken.
Conformity is checked by inspection.
Probe assembly RATING
Documentation shall include the voltage and current RATING (as appropriate), and the
MEASUREMENT CATEGORY as well as a statement of the range of environmental conditions for which the probe assembly is designed (see 1 4)
Conformity is checked by inspection.
Probe assembly operation
Instructions for use must include the identification and operation of controls in all modes, a clear identification of compatible equipment for specific probe assemblies, and an explanation of safety symbols on the probe Additionally, it should define the relevant MEASUREMENT CATEGORY, specify limits for intermittent operation, and provide interconnection instructions for accessories and equipment Cleaning and replacement instructions for consumable materials are essential, along with periodic inspection guidelines for PROBE WIRE without a wear indicator For assemblies with a wear indicator, a warning against use if the indicator is visible is necessary Furthermore, a caution against using probe assemblies without a MEASUREMENT CATEGORY rating for mains circuits should be included, especially for Type B probe assemblies with lower-rated PROBE WIRE voltage.
The rated voltage of the probe tip indicates that the probe wire may not offer sufficient protection if it contacts a hazardous live part Additionally, it is important to note that the applicable measurement category for a combination of a probe assembly and an accessory is determined by the lower measurement category of either the probe assembly or the accessory.
The instructions must include a statement indicating that using the probe assembly in a manner not specified by the manufacturer may compromise its protective features.
Conformity is checked by inspection.
Probe assembly maintenance and service
Detailed instructions must be given to the RESPONSIBLE BODY to facilitate safe maintenance and inspection of the probe assembly, ensuring its continued safety following these procedures.
The manufacturer shall specify any parts which are required to be examined or supplied only by the manufacturer or his agent
The RATING and characteristics of fuses used shall be stated (see 5.1 3)
Service personnel will receive instructions on essential topics to ensure the safe servicing and ongoing safety of the probe assembly, provided it is deemed suitable for servicing These topics include: a) identification of product-specific risks that may impact service personnel; b) implementation of protective measures against these risks; and c) procedures for verifying the safe condition of the probe assembly following repairs.
Instructions for service personnel do not need to be supplied to the RESPONSIBLE BODY, but should be made available to service personnel
Conformity is checked by inspection
General
Protection against electric shock shall be maintained in NORMAL CONDITION and SI NGLE FAULT CONDITION ACCESSIBLE parts of probe assemblies shall not be HAZARDOUS LIVE (see 6.3)
In situations where it is impractical to ensure that certain components are both inaccessible and not live, these parts may remain accessible to the operator during normal operation, even if they are hazardous live This includes components intended for replacement by the operator, such as fuses.
HAZARDOUS LIVE during replacement, but only if they have warning markings in accordance with 5.2; b) PROBE TIPS, provided that they meet the requirements of 6.4.3; c) unmated CONNECTORS as specified in 6.4.2 c)
Conformity is checked by the determination of 6 2 and the measurements of 6.3, followed by the tests of 6.4 to 6.7.
Determination of ACCESSIBLE parts
General
The determination of whether a part is ACCESSIBLE is outlined in sections 6.2.2 and 6.2.3, where test fingers and pins are used without applying force A part is deemed ACCESSIBLE if it can be touched by any part of a test finger or pin, or if it could be touched without a covering that does not provide adequate insulation, as specified in section 6.7.2.
In normal use, operators should take any necessary actions to enhance the accessibility of parts, whether using a tool or not, prior to conducting the examinations outlined in sections 6.2.2 and 6.2.3.
NOTE Examples of such actions include: a) removing covers; b) adjusting controls; c) replacing consumable materials; d) removing or installing parts and supplied accessories
Figure 6 gives methods for determination of ACCESSIBLE parts of probe assemblies.
Examination
The jointed test finger (see Figure B.2) is applied in every possible position without force The test is applied to all outer surfaces
1 accessory PROBE TI P 4 CON NECTOR
2 PROBE TI P 5 CON NECTOR to equipment
Figure 6a – Parts of a probe assembl y
Figure 6b – Full y-mated probe assembl y (see 6.2 and 6.4.2 a)
Connecting parts are partially mated so as just to make electrical contact while allowing maximum access to the test finger
Figure 6c – Partiall y-mated probe assembl y (see 6.2 and 6.4.2 b)
F rigid test finger (see Figure B.1 )
H potentially H AZARDOU S LI VE part
Figure 6d – Unmated parts of a probe assembl y (see 6.2 and 6.4.2 c))
Figure 6 – Methods for determination of ACCESSIBLE parts (see 6.2) and for voltage tests of (see 6.4.2)
Openings for pre-set controls
A 3 mm diameter metal test pin is used to access pre-set controls that typically require a screwdriver or other tools The pin can be inserted in various directions through the designated hole, but its penetration must not exceed three times the distance from the enclosure surface to the control shaft, or 100 mm, whichever is less.
Limit values for ACCESSIBLE parts
General
The voltage between any accessible part and earth, or between two accessible parts on the same probe assembly, must not exceed the limits specified in section 6.3.2, unless otherwise permitted in section 6.1.
NORMAL CONDITION or of 6.3.3 in SINGLE FAULT CONDITION
Outer conductors (shields) of probe assemblies, intended to be floating, are considered to be held at the same voltage as the PROBE TIP
The ACCESSIBLE voltage must be measured as outlined in section 6.3.4 If the voltage is below the thresholds specified in sections 6.3.2 a) or 6.3.3 a), there is no need to measure the touch current and capacitance However, if the voltage exceeds these levels, both the touch current and capacitance must be measured Additionally, for high-frequency test probes, the alternative method described in section 6.3.4.3 may be utilized.
Conformity is checked by inspection and as specified in 6 3 2 to 6 3.3
Levels in NORMAL CONDITI ON
Voltages exceeding 30 V r.m.s (42.4 V peak) for a.c and 60 V for d.c are classified as HAZARDOUS LIVE when combined with specific conditions For probe assemblies designed for WET LOCATIONS, the applicable a.c voltage levels must be considered.
1 6 V r.m.s or 22,6 V peak, and the d.c voltage level is 35 V b) The touch current levels are:
For sinusoidal waveforms, a measurement of 0.5 mA r.m.s is required, while for non-sinusoidal waveforms or mixed frequencies, a peak measurement of 0.7 mA is necessary, or 2 mA d.c can be used, as indicated in Figure A.1 If the frequency is 100 Hz or lower, the measuring circuit shown in Figure A.2 is applicable Additionally, the measuring circuit in Figure A.5 is specifically designed for probe assemblies intended for use in wet locations.
2) 70 mA r.m.s when measured with measuring circuit of Figure A.3 This relates to possible burns at frequencies above 1 00 kHz c) The levels of capacitive charge or energy are:
1 ) 45 àC charge for voltages up to 1 5 kV peak or d.c Line A of Figure 7 shows the capacitance versus voltage for cases where the charge is 45 àC
2) 350 mJ stored energy for voltages above 1 5 kV peak or d.c.
Levels in SI NGLE FAULT CONDITION
In SINGLE FAULT CONDITION, voltages exceeding 50 V r.m.s (70.7 V peak) for a.c and 120 V for d.c are considered HAZARDOUS LIVE if any of the specified voltage levels are surpassed simultaneously For probe assemblies designed for WET LOCATIONS, the a.c voltage levels must also be taken into account.
33 V r.m.s or 46,7 V peak, and the d.c voltage level is 70 V b) The touch current levels are:
For sinusoidal waveforms, a measurement of 3.5 mA r.m.s is required, while for non-sinusoidal waveforms or mixed frequencies, a peak measurement of 5 mA is necessary In the case of direct current (d.c.), a measurement of 15 mA is applicable when using the measuring circuit shown in Figure A.1 If the frequency is 100 Hz or lower, the measuring circuit depicted in Figure A.2 can be utilized Additionally, the measuring circuit in Figure A.5 is specifically designed for probe assemblies intended for use in wet locations.
2) 500 mA r.m.s when measured with the measuring circuit of Figure A.3 This relates to possible burns at frequencies above 1 00 kHz c) The capacitance level is line B of Figure 7
B = SI N GLE FAULT CON DI TI ON
Figure 7 – Capacitance level versus voltage in NORM AL CONDITION and SINGLE -FAULT CONDITION (see 6.3.2 c) and 6.3.3 c))
Measurement of voltage and touch current
Voltage and touch current measurements on accessible parts of probe assemblies are conducted by wrapping metal foil around specific components These components include the probe body, a section of the probe wire measuring 150 mm ± 20 mm or the maximum cable length if shorter, hand-held or hand-manipulated parts of each connector, and other similar parts.
The RATED voltage to earth is applied between the PROBE TIP and the earth, with measurements taken between the foil and the earth If needed, the measurement circuit can be sequentially connected between each foil-wrapped item and the earth.
2 Measurement of voltage or touch current (see annex A for applicable measuring circuits for touch current measurements)
2a Connection to metal foil tightly wrapped around parts intended to be hand-held or hand-manipulated 2b Connection to metal foil tightly wrapped around the CON NECTOR
2c Connection to metal foil tightly wrapped around the cable (see 1 2.3.2)
3 Maximum RATED voltage with connection to internal conductor of the PROBE WI RE
4 Not connected to test or measuring equipment
Figure 8 – Voltage and touch current measurement
1 P ROBE TI P of the reference CON NECTOR
2 Measurement of voltage or touch current (see annex A for applicable measuring circuits for touch current measurements)
3 Maximum RATED voltage for the reference CONN ECTOR
Figure 9 – Voltage and touch current measurement for the reference CONNECTOR
6.3.4.2 Probe assemblies with floating outer conductors
In probe assemblies designed for floating outer conductor (shield) connections, testing is conducted between the outer conductor probe tip and the earth, as illustrated in Figure 10.
The touch current is determined by using the applicable measuring circuit of Annex A
2 Measurement of voltage or current (see Annex A for applicable measuring circuits for touch current measurements)
2a Connection to metal foil tightly wrapped around parts intended to be hand-held or hand-manipulated 2b Connection to metal foil tightly wrapped around the CON NECTOR
2c Connection to metal foil tightly wrapped around the cable (see 1 2.3.2)
3 Maximum RATED voltage with connection to outer conductor PROBE TI P
4 Not connected to test or measuring equipment
5 A floating PROBE TI P connected to the shield or outer conductor of the PROBE WI RE
Figure 1 0 – Voltage and touch current measurement with shielded test probe
For test probes rated for frequencies exceeding 100 kHz with a floating outer conductor (shield), it is essential to determine the maximum allowable voltage between the shield and accessible parts of the probe to prevent electrical burns Additionally, the touch current must be measured across the entire frequency range at the maximum voltage for each frequency range.
Measurements were conducted as illustrated in Figure 10, focusing on three key areas: a) the distance between the shield and the foil surrounding the probe body (2a), b) the distance between the shield and the foil encasing the coaxial connector (2b), and c) the distance between the shield and the foil around the probe wire (2c).
Alternative to the touch current measurement, the capacitance between the shield and the foil can be measured for the cases a) to c)
The capacitance \( C_s \), which is the measured capacitance between the shield and the foil, along with the circuit from A.3, determines the impedance illustrated in Figure A.4 The variable parameters affecting this impedance are the capacitance \( C_s \) and the frequency, while \( R_1 \), \( C_1 \), and \( R_2 \) remain constant By utilizing these two parameters, the maximum allowable voltage for the test probe can be calculated, particularly for a permissible touch current of 70 mA.
35 V over R2) as shown in Figure 11 for some values of the capacitance Cs
The maximum voltage for each frequency can then be calculated
NOTE In practice for the calculation with frequencies above 100 kHz, the values of R1 and C1 can be ignored
1 0 pF between probe (shield) and foil
20 pF between probe (shield) and foil
50 pF between probe (shield) and foil
1 00 pF between probe (shield) and foil
Figure 1 1 – Maximum test probe input voltage for 70 mA touch current
Means of protection against electric shock
General
CONNECTORS shall meet the requirements of 6.4.2
PROBE TIPS shall meet the requirements of 6.4.3
To ensure safety, all accessible parts of probe assemblies must be protected from becoming hazardous live under both normal and single fault conditions This can be achieved through various means, including: a) double insulation, which combines basic insulation with supplementary insulation; b) basic insulation paired with enclosures or protective finger guards; c) basic insulation along with impedance; d) reinforced insulation; and e) protective impedance.
NOTE The PROBE WI RE is considered to be hand-held Also see Clause 1 2 for requirements pertaining to the PROBE WI RE
Conformity is checked by inspection and as specified in 6.4.2 to 6 4 6, as applicable.
C ONNECTORS
Insulation, ACCESSIBLE parts and SPACINGS for CONNECTORS of probe assemblies shall meet the applicable requirements of a) to c) below
Annex E provides information regarding the recommended dimensions of 4 mm CONNECTORS a) CONNECTORS in fully-mated position
Accessible parts of connectors, designed solely for linking the probe assembly to test or measurement equipment, must be insulated from hazardous live parts using basic insulation, as they are not meant to be hand-held during measurement operations.
2) ACCESSIBLE parts of CONNECTORS which are used for any other purpose or which are intended to be hand-held during the measurement operation shall be insulated from
Hazardous live parts are protected by double insulation or reinforced insulation Compliance is verified by identifying accessible parts as outlined in section 6.2 and section 6.4.6, which pertain to basic insulation and reinforced insulation Additionally, connectors in a partially-mated position are also considered in this assessment.
ACCESSIBLE parts of CONNECTORS in partially-mated condition shall be insulated from
Hazardous live parts are protected by basic insulation Conformity is verified by identifying accessible parts as outlined in section 6.2 and further detailed in section 6.4.6 for basic insulation, including connectors in their unmated position.
When the RATED voltages to earth are applied to other CONNECTORS or PROBE TIPS of the probe assembly,
1 ) Conductive parts of locking-type or screw-held-type CONNECTORS including
CONNECTORS which do not require the use of a TOOL for unlocking or unscrewing are permitted to be ACCESSIBLE while they are in unmated position,
2) unmated integrated TERMINALS of STACKABLE CONNECTORS shall be protected by BASIC INSULATION,
3) Conductive parts of other unmated CONNECTORS shall be prevented from becoming
Hazardous live parts must be protected by impedance or must meet specific spacing requirements For unmated connectors with a voltage rating up to 1,000 V a.c or 1,500 V d.c., the applicable spacings are defined in Table 2, measured from the closest approach of a test finger touching the external parts of the connector in the least favorable position For unmated connectors with voltage ratings exceeding 1,000 V a.c., additional considerations apply.
1 500 V d.c., the SPACINGS shall not be less than 2.8 mm and shall withstand the voltage test of 6.6 with a test voltage equal to the RATED voltage of the CONNECTOR multiplied by 1 ,25
Table 2 – SPACINGS for unmated CONNECTORS RATED up to
1 000 V a.c or 1 500 V d.c with HAZARDOUS LIVE conductive parts
Voltage on conductive parts of CON NECTOR S PACING
Conformity is verified through inspection by measuring current or voltage to ensure they remain within the specified limits of 6.3 This includes identifying ACCESSIBLE parts as outlined in section 6.2 (refer to Figure 6 c)) and assessing the required SPACINGS Additionally, if necessary, the voltage test described in section 6.6 is conducted.
Insulation covers or sleeves on connectors that can be easily manipulated by the operator without tools do not offer sufficient protection against electric shock For instance, retractable insulation sleeves fail to provide adequate safety They are only deemed acceptable when necessary for connecting to test or measurement equipment.
TERMI NALS which cannot accept fully shrouded CONNECTORS
Conformity is checked by inspection.
P ROBE TIPS
PROBE TIPS that can become HAZARDOUS LIVE during NORMAL USE (see also 6.1 b)) shall meet the requirements of one of 6.4.3.2, 6.4.3.3, or 6.4.3.4
PROBE TIPS that can be used as CONNECTORS shall also meet the requirements of 6.4.3.5
NOTE See Clause 1 3 for additional requirements for the exposed conductive parts of PROBE TI PS
Spring-loaded clips and similar probes designed to pierce wire insulation for voltage measurement must not exceed a voltage rating specified in section 6.3.2 a).
Conformity is checked by inspection and measurement
6.4.3.2 Protection by a PROTECTIVE FINGERGU ARD
To minimize the risk of accidental contact with exposed conductive parts of a probe tip that may become hazardous live, it is essential to install a protective finger guard This guard not only reduces the likelihood of touching dangerous areas but also serves as a visual indicator of the safe limits for handling the probe during operation.
SPACINGS between the HAZARDOUS LIVE part of the PROBE TIP and the hand-held side of the
PROTECTIVE FINGERGUARD shall be those specified for REINFORCED INSULATION
The PROTECTIVE FINGERGUARD must have a minimum height of 2 mm on the side where fingers are applied, and its thickness should not exceed twice the height.
The PROTECTIVE FINGERGUARD for probe assemblies with a voltage RATING exceeding 6.3.2 a) must cover at least 80% of the sides where fingers are meant to be applied.
Figure 1 2 gives an example of a probe assembly with a PROTECTIVE FINGERGUARD and indicates applicable SPACINGS
2 CREEPAGE DI STANCE (along surface)
4 hand-held area of probe body
5 PROTECTI VE FI N GERGU ARD
Figure 1 2 – Protection by a PROTECTIVE FINGERGU ARD
SPRI NG-LOADED CLIPS RATED for voltages to earth up to 1 kV are acceptable without a
PROTECTIVE FINGERGUARD provided that: a) actuation of the spring-loaded mechanism prevents the OPERATOR from touching a
The hazardous live part requires increased spacing between the probe tip and the nearest surface that the operator must touch to activate the mechanism, ensuring an additional protective distance for safety.
Figure 1 3 gives an example of a probe assembly protected by distance and indicates applicable SPACINGS
2 CLEARAN CE and CREEPAGE DI STANCE as specified in 6 5
5 hand-held area of the probe assembly
Spring-loaded clips classified under Measurement Category II can be used without a protective finger guard, as long as they require finger pressure at approximately 90° to the clip's axis and include a tactile indicator to mark the safe access limit for the operator.
Figure 1 4 gives an example of a SPRING-LOADED CLIP with a tactile indicator
Figure 1 4 – Protection by tactile indicator
6.4.3.5 P ROBE TIPS used as CONNECTORS
Probe tips designed as connectors, such as those intended for use with a spring-loaded clip, must comply with the connector requirements in both fully-mated and partially-mated positions (refer to sections 6.4.2 a) and b)).
Impedance
Impedance, when used alongside BASIC INSULATION, must fulfill specific criteria to ensure safety and effectiveness It should limit current or voltage to levels specified in section 6.3.3, be rated for the WORKING VOLTAGE and the power it will dissipate, and maintain appropriate SPACINGS between terminations as outlined in section 6.5 for BASIC INSULATION.
Conformity is verified through inspection, which includes measuring voltage or current to ensure they remain within the limits set by section 6.3.3 Additionally, clearance and creepage distance are assessed according to the specifications outlined in section 6.5.
P ROTECTIVE IMPEDANCE
A PROTECTIVE IMPEDANCE shall limit the current or voltage to the levels of 6.3.2 in NORMAL CONDITION and 6.3.3 in SI NGLE FAULT CONDITION (see also 4.4.2.2)
Insulation between the terminations of the PROTECTIVE IMPEDANCE shall meet the requirements of 6.4.6 for DOUBLE INSULATION or REINFORCED INSULATION
A PROTECTIVE IMPEDANCE shall be one or more of the following:
2 a) an appropriate single component which shall be constructed, selected and tested so that safety and reliability for protection against electric shock is assured In particular, the component shall be:
1 ) RATED for twice the WORKING VOLTAGE;
2) if a resistor, RATED for twice the power dissipation for the WORKING VOLTAGE;
3) if a capacitor, RATED for the maximum transient overvoltage; b) a combination of components
When a combination of components is used, the SPACINGS shall take into account the
WORKING VOLTAGE across each insulation
A PROTECTIVE I MPEDANCE shall not be a single electronic device that employs electron conduction in a vacuum, gas or semiconductor
Conformity is verified through inspection, which includes measuring current or voltage to ensure they remain within the specified limits of 6.3, as well as assessing SPACINGS according to section 6.5 Additionally, the conformity of individual components is confirmed by inspecting their RATING.
B ASIC INSULATION , SUPPLEMENTARY INSULATION , DOUBLE INSULATION and
SPACINGS and solid insulation forming BASIC INSULATION, SUPPLEMENTARY INSULATION or
REINFORCED INSULATION between ACCESSIBLE parts and HAZARDOUS LIVE parts shall meet the applicable requirements of 6.5
DOUBLE INSULATION is comprised of BASIC INSULATION and SUPPLEMENTARY I NSULATION, each of which shall meet the applicable requirements of 6.5
Conformity is checked as specified in 6.5.
Insulation requirements
The nature of insulation
Insulation between circuits and ACCESSIBLE parts (see 6.2) or between separate circuits consists of SPACINGS, solid insulation, or a combination of SPACINGS and solid insulation
SPACINGS comprise both CLEARANCES and CREEPAGE DISTANCES
To ensure safety against hazards, insulation must be capable of withstanding the electrical stresses generated by the voltages present on various components of the probe assembly.
The requirements for insulation depend on: a) the required level of insulation (BASIC INSULATION, SUPPLEMENTARY INSULATION, or
Reinforced insulation is essential for ensuring safety in electrical circuits, particularly in relation to the maximum transient overvoltage that can occur due to external events like lightning strikes or switching transients, as well as from the operation of the probe assembly Additionally, it is crucial to consider the working voltage and the pollution degree of the micro-environment to maintain optimal performance and reliability.
SPACINGS, defined by CLEARANCES and CREEPAGE DISTANCES, are crucial for ensuring that probe assemblies can withstand the voltages present in their intended systems, as outlined in sections 6.5.1.2.2 and 6.5.1.2.3 These spacings are carefully chosen to consider the environmental conditions and any protective devices specified by the manufacturer.
CLEARANCES are designed to endure the highest transient overvoltage that may occur in the circuit during normal operation of the probe assembly In the absence of transient overvoltages, CLEARANCES are determined based on the working voltage.
The CLEARANCES specified in Table 6 and Table 7 are determined under absolute inhomogeneous field conditions However, reduced CLEARANCES may be applicable for constructions designed to achieve a more homogeneous field, as the dielectric strength of an air gap is influenced by both the shape of the electric field and the gap's width.
For more homogeneous constructions, a specific value for reduced CLEARANCE cannot be defined; however, it can be evaluated through a voltage test (refer to section 6.6) CLEARANCES that comply with the values outlined in Table 6 and Table 7 satisfy the requirements for any construction and do not require a voltage test, as they can be verified through measurement alone.
If the probe assembly is RATED to operate at an altitude greater than 2 000 m, the values for
CLEARANCES are multiplied by the applicable factor of Table 3
Table 3 – Multiplication factors for CLEARANCES of probe assembly RATED for operation at altitudes up to 5 000 m
R ATED operating altitude m Multiplication factor
In all cases, the minimum CLEARANCE value for POLLUTION DEGREE 2 is 0,2 mm and for
See Annex C for details of how to measure CLEARANCES
Conformity is checked by inspection, measurement, and in the case of more homogeneous construction by the voltage test of 6 6
CREEPAGE DISTANCES shall be based on the actual WORKING VOLTAGE which stresses the insulation (see Table 9) Linear interpolation of CREEPAGE DISTANCE is permissible
Coatings that meet the requirements of Annex H of IEC 61 01 0-1 :201 0 when applied to the outer surfaces of printed wiring boards reduce the POLLUTION DEGREE of the coated area to
For REI NFORCED I NSULATI ON, the value of the CREEPAGE DISTANCE is twice the value specified for BASIC INSULATION
Creepage distances are essential for preventing surface tracking on insulation, a long-term issue that cannot be verified through voltage testing Instead, these distances must be measured according to the guidelines outlined in Annex C.
Conformity is checked by inspection and measurement
Solid insulation shall withstand the electric and mechanical stresses that may occur in NORMAL USE, in all RATED environmental conditions (see 1 4)
The manufacturer should take the expected life of the probe assembly into account when selecting insulating materials
Conformity is checked by inspection, and by the a.c voltage test of 6.6 5.1, or for probe assemblies stressed only by d.c , the d.c voltage test of 6.6.5 2, with a duration of at least
1 min using the applicable test voltage of Table 4 :
Table 4 – Test voltages for testing solid insulation
Nominal a.c r.m.s or d.c RATED voltage to earth
B ASIC IN SU LATION and SU PPLEMEN TARY INSULATION
B ASIC IN SU LATION and SU PPLEMEN TARY INSULATION
1 ,5 times the RATED voltage to earth or
Twice the RATED voltage to earth or
1 ,5 times the RATED voltage to earth or
Twice the RATED voltage to earth or
Solid insulation must comply with specific requirements based on its application For insulation used as an enclosure or protective finger guard, it must meet the standards outlined in Clause 8 Moulded and potted parts are subject to the criteria in section 6.5.1.2.4.2, while the inner layers of printed wiring boards must adhere to the requirements specified in section 6.5.1.2.4.3 Additionally, thin-film insulation is governed by the standards set forth in section 6.5.1.2.4.4.
Conformity is checked as specified in 6 5 1.2.4 2 to 6.5 1.2.4 4, and in Clause 8, as applicable
For BASIC INSULATION, SUPPLEMENTARY INSULATION, and REINFORCED INSULATION, conductors situated at the interface of two molded layers must maintain a minimum separation distance as specified in Table 5, following the completion of the molding process.
Conformity is checked by inspection and either by measurement of the separation or by inspection of the manufacturer’s specifications
Figure 1 5 – Distance between conductors on an interface between two layers
6.5.1 2.4.3 Insulating layers of printed wiring boards
For BASIC INSULATION, SUPPLEMENTARY INSULATION, and REINFORCED INSULATION, conductors situated between the same two layers must maintain a minimum separation distance as specified in Table 5.
Conformity is checked by inspection and either by measurement of the separation or by inspection of the manufacturer’s specifications
L Distance between conductors on the same surface
Figure 1 6 – Distance between adjacent conductors along an interface of two layers
Table 5 – Minimum values for distance or thickness
Minimum distance L (see Figure 1 6) a mm
For insulation systems, values ranging from 600 to 1,000 volts are applicable for basic, supplementary, and reinforced insulation For voltages exceeding 1,000 volts, a partial discharge test is recommended, with the testing procedure currently under consideration.
Reinforced insulation of the insulating layers in printed wiring boards must possess sufficient electric strength across the respective layers To achieve this, one of the following methods should be implemented: the insulation thickness must meet or exceed the values specified in Table 5.
Conformity is verified through inspection, which includes measuring the separation or reviewing the manufacturer's specifications The insulation consists of a minimum of two distinct layers of printed wiring board materials, each rated by the manufacturer for an electric strength that meets or exceeds the test voltage specified in Table 4 for basic insulation.
Conformity is verified through an inspection of the manufacturer's specifications The insulation consists of a minimum of two distinct layers of printed wiring board materials, and the manufacturer rates this combination for electric strength, ensuring it meets or exceeds the test voltage values specified in Table 4 for reinforced insulation.
Conformity is checked by inspection of the manufacturer’s specifications
For BASIC INSULATION, SUPPLEMENTARY INSULATION, and REINFORCED INSULATION, conductors located between the same two layers (see Figure 1 7, item L).shall be separated by at least the applicable SPACI NGS
Conformity is checked by inspection and either by measurement of the separation or by inspection of the manufacturer’s specifications
A layers of thin-film material such as tape and polyester film
NOTE There might be air present between the layers
Figure 1 7 – Distance between adjacent conductors located between the same two layers
Reinforced insulation must possess sufficient electric strength through the layers of thin-film insulation To ensure this, the insulation thickness should meet or exceed the values specified in Table 5.
Insulation requirements for probe assemblies
Measuring circuits experience working voltages and transient stresses from the connected circuit during tests When measuring mains supplies or circuits directly linked to them, the transient stresses can be assessed based on the measurement location within the installation For other electrical signals, operators must consider transient stresses to ensure they remain within the probe assembly's capabilities.
6.5.2.2 C LEARANCES for probe assemblies of MEASUREMENT CATEGORIES II, III and IV
CLEARANCES for probe assemblies of MEASUREMENT CATEGORIES II, III and IV are specified in Table 6
Table 6 – C LEARANCES for probe assemblies of MEASUREMENT CATEGORIES II, III and IV
Nominal a.c r.m.s line-to-neutral or d.c voltage of mains to which the probe assembl y is designed to be connected
B ASIC IN SU LATION and SUPPLEMEN TARY INSULATION R EINFORCED I NSULATION
M EASUREM EN T CATEGORY II M EASUREM EN T
Conformity is verified through inspection and measurement, or by conducting a.c voltage tests as specified in section 6.6.5.1 for a minimum duration of 5 seconds Alternatively, impulse voltage tests outlined in section 6.6.5.3 may be used For probe assemblies subjected solely to d.c., a 1-minute d.c voltage test from section 6.6.5.2 or the impulse voltage test from section 6.6.5.3 should be performed, utilizing the test voltage indicated in Table 10 to ensure the necessary clearance.
6.5.2.3 C LEARANCES for probe assemblies which are not RATED for MEASUREMENT
CATEGORIES II, III, or IV 6.5.2.3.1 General
CLEARANCES for probe assemblies which are not RATED for MEASUREMENT CATEGORIES II, III, or IV are calculated according to 6.5.2.3.2
Clearances are determined according to section 6.5.2.3.3 when specific characteristics are present The required clearance is the larger value between two options: a) when the working voltage features a recurring peak voltage, which may consist of a periodic non-sinusoidal waveform or a regularly occurring non-periodic waveform; b) when the working voltage operates at a frequency exceeding 30 kHz.
CLEARANCES for BASIC INSULATION and SUPPLEMENTARY INSULATION are determined from the following formula:
F is a factor, determined from one of the equations:
U w = the maximum peak value of the WORKING VOLTAGE;
U t = the maximum additional transient overvoltage
D 1 and D 2 are values taken from Table 7 for U m where
D 1 represents the CLEARANCE that would be applicable to a transient overvoltage with the shape of a 1 ,2 ì 50 às impulse
D 2 represents the CLEARANCE that would be applicable to the peak WORKING VOLTAGE without any transient overvoltage
CLEARANCES for REINFORCED INSULATION are twice the values for BASIC INSULATION
Conformity is verified through inspection and measurement, or by conducting the a.c voltage test specified in section 6.6.5.1 for a minimum duration of 5 seconds, or the impulse voltage test outlined in section 6.6.5.3, utilizing the relevant voltage from Table 10 to ensure the necessary clearance.
Table 7 – CLEARANCE values for the calculation of 6.5.2.3.2
NOTE The following is an example calculation:
Clearance for reinforced insulation is required for a working voltage with a peak value of 3,500 V, along with an additional transient voltage of 4,500 V, which may occur in electronic switching circuits.
U w / U m = 3 500 / 8 000 = 0,44 > 0,2 thus F = (1 ,25 × U w / U m ) – 0, 25 = (1 ,25 × 3 500 / 8 000) – 0,25 = 0,297 Values derived from Table 7 at 8 000 V:
For REI NFORCED I NSU LATI ON the value is doubled C LEARAN CE = 20,6 mm
6.5.2.3.3 C LEARANCES for probe assemblies subjected to recurring peak voltages, or
WORKING VOLTAGES with frequencies above 30 kHz, or both
Clearances for basic insulation and supplementary insulation in probe assemblies exposed to recurring peak voltages with frequencies up to 30 kHz must comply with the values specified in the second column of Table 8, using the recurring peak voltage as the reference index (refer to Figure 18 for an example of recurring peak voltage).
In practical recurring waveforms, the fundamental frequency typically exhibits a significantly higher amplitude than its harmonics, making it the key factor for assessing whether the waveform frequency surpasses 30 kHz However, for determining SPACINGS, it is essential to consider the peak amplitude of the entire waveform rather than just the fundamental component For further details, refer to E.2 of IEC 60664-4:2005.
A peak value of recurring voltage
Figure 1 8 – Example of recurring peak voltage
Clearances for basic and supplementary insulation in probe assemblies exposed to working voltages exceeding 30 kHz must adhere to the values specified in the third column of Table 8, utilizing the peak value of the working voltage as the reference.
Clearances for basic and supplementary insulation in probe assemblies exposed to recurring peak voltages and working voltages with frequencies exceeding 30 kHz must adhere to the more stringent of the applicable requirements.
CLEARANCES for REINFORCED INSULATION are twice the values for BASIC INSULATION
Conformity is checked by inspection and measurement
Table 8 – CLEARANCES for BASIC INSULATION in probe assemblies subjected to recurring peak voltages or WORKING VOLTAGES with frequencies above 30 kHz
C LEARAN CE Frequencies up to
Creepage distances for basic or supplementary insulation in probe assemblies must adhere to the values specified in Table 9, determined by the working voltage that affects the insulation For reinforced insulation, the required distances are double those of basic insulation Compliance is verified through inspection and measurement.
Table 9 – CREEPAGE DISTANCES for BASIC INSULATION or SUPPLEMENTARY INSULATION
C REEPAGE DISTAN CES Printed wiring board material Other insulating material
P OLLU TION DEGREE P OLLU TI ON DEGREE
V mm mm mm mm mm
Procedure for voltage tests
General
The following test procedures apply to type testing, and deterioration of the test specimen may occur Further use of the test specimen may not be appropriate
Test equipment for the voltage tests is specified in IEC 61180-1 and IEC 61180-2
The reference point for voltage tests includes accessible conductive parts, excluding live parts that meet specific criteria, and accessible conductive parts deemed hazardous live under certain exceptions Additionally, it encompasses accessible insulating parts of the enclosure that are covered with metal foil, except around connectors, with a maximum distance of 20 mm from the foil to the connector for test voltages up to 10 kV For higher voltages, the distance must be minimized to prevent flashover Lastly, it includes accessible control parts made of insulating material that are either wrapped in metal foil or have soft conductive material pressed against them.
Humidity preconditioning
To ensure that the probe assembly does not become hazardous in the humidity conditions of
1 4, it is subjected to humidity preconditioning before the voltage tests The probe assembly is not operated during preconditioning
If wrapping in foil is required by 6 6.1, the foil is applied after humidity preconditioning and recovery
Electrical components, covers, and other parts which can be removed by hand are removed and subjected to the humidity preconditioning together with the main part
Preconditioning is carried out in a humidity chamber containing air with a humidity of 93 % RH ± 3 % RH The temperature of the air in the chamber is maintained at 40 °C ± 2 °C
Before applying humidity, the probe assembly is brought to a temperature of 42 °C ± 2 °C, normally by keeping it at this temperature for at least 4 h before the humidity preconditioning
The air in the chamber is stirred and the chamber is designed so that condensation will not precipitate on the probe assembly
The probe assembly is kept in the chamber for 48 hours, followed by a 2-hour recovery period under specific environmental conditions After this time, the previously removed parts are re-installed.
Conduct of tests
The tests are performed and completed within 1 h of the end of the recovery period after humidity preconditioning The probe assembly is not operated during the tests
Voltage tests are not made between two circuits, or between a circuit and an ACCESSIBLE conductive part, if they are connected to each other or not separated from each other
PROTECTIVE IMPEDANCE in parallel with the insulation to be tested is disconnected
When using multiple protective means together, it is important to ensure that the voltages designated for DOUBLE INSULATION and REINFORCED INSULATION are not inadvertently applied to circuit components that do not need to withstand these voltages To prevent this issue, these components can be disconnected during testing, or the sections of the circuit requiring DOUBLE INSULATION or REINFORCED INSULATION can be tested independently.
Test voltages
Voltage tests for solid insulation are applied using the values specified in Table 4
Voltage tests for CLEARANCES are applied using the values specified in Table 10
The CLEARANCE in case of homogeneous construction (see 6.5.1.2.2), is tested with an a.c., d.c., or peak impulse voltage with the peak value specified in Table 10 for the value of
CLEARANCE specified for inhomogeneous construction
Table 10 values are specifically for test sites at an altitude of 2,000 meters For test sites at different altitudes, the correction factors from Table 11 should be used to adjust the values from Table 10 during testing.
CLEARANCE but not when testing solid insulation
NOTE The electric testing of CLEARANCES will also stress the associated solid insulation
Table 1 0 – Test voltages based on CLEARANCES
50/60 Hz or d.c mm V peak V V mm V peak V V
Table 1 1 – Correction factors according to test site altitude for test voltages for CLEARANCES
Correction factors Test voltage peak ≥ 327 V < 600 V ≥ 600 V < 3 500 V ≥ 3 500 V < 25 kV ≥ 25 kV Test voltage r.m.s ≥ 231 V < 424 V ≥ 424 V < 2 475 V ≥ 2 475 V < 1 7,7 kV ≥ 1 7,7 kV Test site altitude m
Test procedures
The voltage test equipment must provide a regulated output that consistently maintains the test voltage during the assessment Additionally, the power frequency test voltage should exhibit a waveform that is predominantly sinusoidal, which is achieved if the ratio of the peak value to the root mean square (r.m.s.) value is within the range of √2 ± 3%.
The test voltage is raised uniformly from 0 V to the specified value within 5 s and held at that value for at least the specified time
No flashover of CLEARANCES or breakdown of solid insulation shall occur during the test
The voltage test equipment must provide a stable output that consistently maintains the test voltage during the evaluation Additionally, the direct current (d.c.) test voltage should exhibit minimal ripple, achieved when the ratio of the peak voltage to the average voltage is 1.0 ± 3%.
The d.c test voltage is raised uniformly from 0 V to the specified value within 5 s and held at that value for at least 1 min
No flashover of CLEARANCES or breakdown of solid insulation shall occur during the test
The impulse voltage test will be performed using five impulses of each polarity, ensuring a minimum interval of 1 second between each impulse This test follows the 1, 2/50 µs waveform as specified in Figure 1 of IEC 61180-1:1992, and it is essential to monitor the wave shape of each impulse during the testing process.
When verifying CLEARANCES within probe assembly by an impulse voltage test, it is necessary to ensure that the specified impulse voltage appears at the CLEARANCE
No flashover of CLEARANCES or breakdown of solid insulation shall occur during the test, but partial discharges are allowed.
Constructional requirements for protection against electric shock
General
To prevent hazards from failures, it is essential that wiring connections under mechanical stress are not solely reliant on soldering Additionally, screws that secure removable covers must be captive if their length creates a gap between accessible conductive parts and hazardous live components Furthermore, any accidental loosening or detachment of wiring or screws should not result in accessible parts becoming hazardous live.
NOTE Screws or nuts with lock washers are not regarded as likely to become loose, nor are wires which are mechanically secured by more than soldering alone
Conformity is checked by inspection and by measurement of SPACINGS.
Insulating materials
For safety purposes, insulation materials that should be avoided include easily damaged substances such as lacquer, enamel, oxides, and anodic films, as well as non-impregnated hygroscopic materials like paper and fibrous materials Compliance with these guidelines is verified through inspection.
E NCLOSURES of probe assemblies with DOUBLE INSULATION or REINFORCED
A probe assembly that utilizes double insulation or reinforced insulation for electric shock protection must feature an enclosure that encases all metal components However, this requirement is exempt for small metal parts like nameplates, screws, or rivets, provided they are adequately separated from hazardous live parts by reinforced insulation or an equivalent barrier.
ENCLOSURES or parts of ENCLOSURES made of insulating material shall meet the requirements for DOUBLE INSULATION or REINFORCED INSULATION
Protection for metal enclosures or their components must be ensured through specific methods, excluding areas utilizing protective impedance This can be achieved by applying an insulating coating or barrier on the interior of the enclosure, covering all metal parts and locations where a hazardous live component may come into contact with the enclosure Additionally, maintaining adequate spacing between the enclosure and hazardous live parts is essential, ensuring that these distances do not fall below the values outlined in section 6.5 due to any loosening of components or wires.
Conformity is checked by inspection and measurement and as specified in 6 5.
P ROBE WIRE attachment
The attachment of the PROBE WIRE to the probe body and to the equipment (or to the
CONNECTORS if the attachment is not fixed) shall withstand forces likely to be encountered in
Proper usage of the probe wire is essential to prevent hazards, ensuring that solder is not solely relied upon for strain relief without mechanical support Additionally, the insulation of the probe wire must be securely fastened to prevent any retraction.
Conformity is verified through inspection and the application of tests 6.7.4.2 to 6.7.4.4 The results must show that the PROBE WIRE is undamaged, its insulation is intact without cuts or tears, and it has not shifted more than 2 mm in the bushing Additionally, SPACINGS must meet the minimum requirements specified in section 6.5, and the PROBE WIRE must successfully pass either the a.c or d.c voltage test outlined in section 6.6, using the appropriate test voltage and duration from Table 4, without humidity preconditioning.
For testing purposes, it may be beneficial to create a special sample of the probe that is identical to the probe under investigation, except that it has no solder applied.
The probe wire must be securely clamped to prevent movement, and any soldered connections should be severed It is then subjected to a steady axial pull for one minute, with specific force values: for probe bodies and locking connectors, the pull force should be twice the value indicated in Table 12; for non-locking connectors, it should be either twice the value from Table 12 or four times the axial pull force needed to disconnect the connector, whichever is lower.
CONNECTORS shall be subjected to a flexing test in an apparatus similar to that shown in Figure 19
The CONNECTOR is securely attached to the oscillating member of the apparatus, ensuring that when the member is at the midpoint of its travel, the axis of the flexible PROBE WIRE entering the CONNECTOR is vertical and aligned with the axis of oscillation.
The oscillating member is adjusted by varying the distance \(d\) to ensure that the flexible probe wire experiences minimal lateral movement during the full travel of the test apparatus.
2 Part of oscillating member for fixing the CONNECTOR
3 Depth specified for the shroud of corresponding equipment TERMI NAL
Figure 1 9 – Flexing test The PROBE WIRE is loaded with a weight such that the force from Table 12 is applied
The oscillating member moves 90° in total, with 45° on each side of the vertical It undergoes 5,000 flexings at a rate of 60 flexings per minute, with each complete cycle consisting of two flexings.
CONNECTORS with PROBE WIRE of nominally circular cross-sectional area are rotated approximately 90° around the vertical axis within the oscillating member after 2 500 flexings;
CONNECTORS with flat flexible PROBE WIRE are not so rotated, and are only flexed in a direction perpendicular to the thinner dimension of the cross-section
In testing for hazards associated with conductor breakage or short-circuits, a current equal to the rated current of the probe assembly is applied to each conductor, with the voltage maintained at the rated voltage It is crucial that the test current remains uninterrupted and that no short-circuit occurs between the conductors during the testing process.
Table 1 2 – Pull forces for PROBE WIRE attachment tests
Cross sectional area of the conductor (a) Pull force mm 2 N
For PROBE WI RES with multiple conductors, the cross-sectional area (a) is calculated as the sum of the cross-sectional areas of the individual conductors
For the purpose of this calculation, the cross-sectional area of any shield is ignored
The probe assembly is securely positioned in the test fixture, as illustrated in Figure 20, ensuring that the fixed clamp holds the probe body, connector, or equipment with a minimum of 5 mm of the solid portion extending through the clamp Additionally, the rotating clamp is connected to the probe lead at a designated point.
The PROBE WIRE's diameter is measured at 50 times along the lead's surface from the fixed clamp The rotating clamp operates at a distance of 20 times the PROBE WIRE's diameter from the fixed clamp It completes a full oscillation from point F to G and back to F at a frequency of 20 oscillations per minute.
250 swings The probe body or CONNECTOR is turned 90° about its axis and the test continued for a further 250 oscillations
Key d diameter of PROBE WI RE
Handling of a probe assembly or an accessory during NORMAL USE shall not lead to a HAZARD
Easily touched edges, projections, etc should be smooth and rounded so as not to cause injury This does not apply to PROBE TIPS
Conformity is checked by inspection