Safety requirements for short wave single sideband communication equipment
Some standard content:
Military Standard of the Electronic Industry of the People's Republic of China FL5820
Safety requirements for short wave single sideband communication
Equipment
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Safety requirements for short wavesingle sideband communication equipment1992-02-01 Issued
China Electronics Industry Corporation
1992-05-01 Implementation
Military Standard of the Electronic Industry of the People's Republic of China Safety requirements for short wave single sideband communication equipment Safety requirements for short wave singlesideband communication equipment Subject content and scope of application
This standard specifies the safety requirements for short wave single sideband communication equipment. SJ20044-92
This standard applies to short wave single sideband communication equipment and any auxiliary equipment necessary for the normal operation of the equipment, including combination units and matching networks.
The use of this standard is not limited to type testing, but can also be used for acceptance testing after equipment installation, testing after equipment component changes, and testing at appropriate time intervals to ensure the continued safety of the equipment throughout its life. 2 Reference standards
GB4207—84
GB4728.2-85
GB5169—85
GB5465.2—82
GB8898—88
GB9159--88
GJB 367.2—87
3 Terminology
Method for determining comparative tracking index and resistance tracking index of solid insulating materials under humid conditions
Graphic symbols for electrical diagramsSymbol elements, limiting symbols and other commonly used symbolsFire hazard test for electrical and electronic products
Graphic symbols for electrical equipmentwww.bzxz.net
Safety requirements for household and similar general-purpose electronic and related equipment powered by mains power supplySafety requirements for radio transmitting equipment
General technical conditions for military communication equipmentEnvironmental test methods3.1 Electrical safetyelectrically safe
If a component does not cause harmful electric shock or radio frequency skin burns, the component is electrically safe. The electrical safety conditions of a component are one of the following conditionsa. When measured with an instrument with an internal resistance of not less than 10kQ/V, the peak voltage between the component and the ground or between the component and any other accessible component shall not exceed 72V. b. Although the above voltage exceeds 72V, the current and capacitance shall not exceed the limit values in Tables 1 and 2. China Electronics Industry Corporation issued on February 1, 1992 and implemented on May 1, 1992
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Current limit value
Current limit
0.7 (peak value)
0.7f (peak value)
70 (peak value)
Note: ① The current limit value is measured by connecting a 2kN non-inductive resistor between the component and the ground or between the component and any other accessible components.
②f represents the frequency value in kHz. Table 2 Capacitance limit value
Voltage range (peak value)
72~450
45015000
>15000
Capacitance limit
675000/U3
Note: ①Capacitance limit value refers to the capacitance value between the component and the ground or between the component and any other accessible component. ②U shows the peak voltage value in V. The internal resistance of the peak voltage measuring instrument should not be less than 10kn/V3.2 Creepage distance
The shortest distance measured in the air along the surface of the insulator between two conductive parts. 3.3 Clearance
The shortest distance measured in the air between two conductive parts. 3.4 By hand
Operation that does not require the use of tools, coins or any other objects. 3.5 Accessible part accessible part
Part that can be touched when the standard finger-shaped test rod described in GB8898 is inserted in any direction with a force not exceeding 50N. 3.6 Enclosure
A space where dangerous equipment parts are placed, which cannot be entered except through specially provided means, such as doors or removable covers.
3.7 Safety device
safetydevice
Any part or component used to protect personnel from possible harm. 3.8 Live part
Part with which contact may cause obvious electric shock. 3.9 Terminal device
Part used to connect to external wires or other equipment, which may contain several contacts. 3.10 Safety grounding terminal safetyearth terminal A terminal for connecting parts that must be grounded for safety reasons. 2
3.11 Basic insulationbasicinsulation
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Insulation added to provide basic protection against electric shock for live parts. 3.12 Supplementary insulationsupplementaryinsulation An independent insulation added to basic insulation so as to prevent electric shock in case of failure of basic insulation. 3.13 Double insulationdoubleinsulation Insulation composed of basic insulation and supplementary insulation. 3.14 Reinforced insulationreinforcedinsulation A separate insulation system added to live parts, under the conditions specified in this standard, its protection against electric shock is equivalent to double insulation.
3.15 Comparative tracking indexcomparativetrackingindex The highest voltage value that the surface of the material can withstand 50 drops of electrolyte without tracking. 4 Normal use conditions and fault conditions
4.1 Overview
When designing and manufacturing short-wave single-sideband communication equipment, it should be ensured that no danger occurs during normal use or under fault conditions. This chapter specifies the normal use conditions and fault condition ranges under which the equipment can work without danger to personnel. When the equipment works under the normal use conditions given in Article 4.2 and the initial faults listed in Article 4.3 are applied, the safety requirements of this standard shall be met. 4.2 Normal use conditions
a. The standard test atmospheric conditions of the equipment are as follows: temperature: 15~35℃;
Relative humidity: 4575%;
Air pressure: 86~106kPa
The above conditions can be formulated with a more stringent range after consultation between the manufacturer and the user. The power supply voltage and frequency should be within the design range of the equipment. b.
For AC-powered equipment, the power supply voltage waveform should be a basic sine wave. For AC and DC dual-use equipment, the two power supplies should be supplied separately. If there is a safety grounding terminal or contact, it should be reliably connected to the ground. Other grounding terminals should also be reliably connected to the ground. If there are doors and covers or other protective covers for entry and exit, they should be closed or fixed in their positions. The equipment works in any position specified by the design. The equipment controller is accessible at any position. The equipment operates under any input and output signal conditions specified in its specifications. All connectors that are not used during normal operation of the equipment should be protected (for example, with plastic covers). 4.3 Fault conditions
Equipment operating under normal use conditions is considered to be operating under fault conditions when one of the faults listed a to h below and the related faults that occur with it occurs. Fault conditions should be applied in the most convenient order. a.
Short circuit between creepage distances caused by creepage distances less than that specified in Appendix A (Supplement) (unless its insulation complies with the provisions of 3.5).
b. Short circuit between gaps caused by gaps less than that specified in Appendix A (Supplement). C. Failure of any component that is considered to be potentially dangerous by inspection of the equipment and analysis of the circuit diagram, unless it is known that the component meets the safety requirements through tests suitable for its use in the equipment. 3
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Impedance mismatch connection at the RF output, including open circuit and short circuit. Short circuit of the AC or DC power connector. Failure of the cooling system.
A motor intended for intermittent operation is operated continuously unless there are protective measures in the equipment for this purpose. f.
The moving parts of a rotating or linear motion device are stuck due to mechanical failure. A phase of the three-phase power supply is missing.
5 Marking
5.1 General requirements
5.1.1 Safety signs should remain legible and easy to identify throughout the life of the equipment. Check visually and verify with the following test.
The mark should not be wiped off by gently wiping with a cloth soaked in gasoline or water. b. When exposed to sunlight, the mark should not be difficult to identify due to the root color. 5.1.2 The text of the mark should be in Chinese characters, or English or other characters should be added according to the scope of use. If symbols are used, they should comply with the provisions of Appendix B of GB9159.
5.1.3 Switches and isolators specially set up for the safety of equipment should have clear and visible markings to prevent confusion with other switches.
5.1.4 Parts used to prevent harmful radiation and removable during maintenance should be marked with appropriate warning marks. 6 Components
6.1 General requirements
Under normal conditions, the component load should not exceed its rated value. Try not to exceed its rated value under fault conditions. Components that have been verified to meet safety requirements through tests that are compatible with the conditions under which the components are used in the equipment do not need to be tested.
Components that do not fall into the above conditions must be tested inside or outside the equipment (under conditions equivalent to the conditions under which the components are used in the equipment). The number of components to be tested should be negotiated by the manufacturer and the user. 6.2 Connectors
a. The connector should be designed so that it will not cause harm due to misconnection, and when the normal disconnection method is used, the staff will not be shocked or injured.
b. The structure of the connector should prevent the bare wire connected to it from passing through the connector and ensure that it does not contact other parts. c. The gap and electrical distance between the connector used for auxiliary purposes (such as monitoring) and the connection point in the equipment and other circuits should be at least twice the value specified in Appendix A (Supplement). d. Connectors with non-detachable cords and cables should comply with the requirements of GB8898. 6.3 Switches
a. The switch should have good switching performance and load capacity. b.. The on and off positions of the switch shall be clearly identified. 6.4 Fuse
The fuse element in the fuse shall be encapsulated. The rated value of the fuse shall be marked on its fixed part or near the fuse as much as possible.
6.5 Corrosion-prone parts
The structure of the equipment shall ensure that the failure of any part due to corrosion will not cause harm to personnel. The test shall be agreed upon by the manufacturer and the user.
7 Structure
7.1 General requirements
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a. The design of the equipment shall take into account the maximum convenience and safety for the staff during installation, operation and maintenance. b. The equipment shall be made of non-flammable materials as much as possible and shall have sufficient strength to ensure safety. c. In places where the electrical connection is loose and causes harm, the electrical connection shall be separated from the mechanical connection, and its fixing degree shall be independent of the pressure acting on the insulating material. The screws that serve as both electrical and mechanical connections shall be fully locked. d. Moving parts that may cause personal injury should be adequately protected. e. The mechanical design of the equipment should minimize the possibility of personal injury (for example, injury caused by sharp edges, protruding corners, hot pipes, and heat released by various devices). Warning signs should be placed where personal injury may occur.
f. For parts activated by remote control, appropriate protective measures should be taken to prevent possible injury. g. The design of the equipment should ensure that the center of gravity is at the bottom to prevent tipping over and causing harm to people and machines. h. The design of the equipment should minimize the sound noise to prevent people from suffering hearing and nervous system damage due to excessive noise. In places with loud noise, there should be obvious signs and reminders to wear protective earmuffs. 7.2 Moisture-proof
Inspection The moisture-proof test should be agreed upon by the manufacturer and the user, and should be carried out after the equipment has undergone the corresponding condensation heat test specified in GJB.367.2.
7.3 Waterproof
Equipment that is specified to be waterproof shall remain safe when subjected to tests under conditions agreed upon by the manufacturer and the user. 7.4 Battery placement
Batteries shall be placed in a manner that provides good ventilation to remove harmful gases and vapors, and ensure that electrolyte leakage will not damage other components or injure people. 7.5 Bracket structure
The design of the bracket structure shall prevent the equipment from accidentally falling when it is operating normally in the carrier or in the event of a collision. 8 Protection against harmful electric shock and radio frequency skin burns
8.1 Grounding
8.1.1 Safety grounding terminal
All accessible conductive parts shall be reliably connected to the safety grounding terminal. In addition, the following provisions shall also be met: a. Equipment connected to a fixed power supply line shall use a separate safety grounding terminal, which shall be as close as possible to the grid power terminal and shall be marked with a safety grounding symbol. The material used for the grounding terminal shall be consistent with the grounding copper conductor in terms of electrolytic properties. The grounding connection shall ensure that it cannot be loosened by hand. b. Equipment with non-detachable cords or cables shall comply with the requirements of a above. In addition, the cord or cable used to connect the equipment to the power supply shall contain an insulated grounding wire with a sufficient cross-section, which shall be yellow and green in color and consistent with the requirements of Article 16.1.1 of GB8898. The insulated grounding wire shall be connected to the safety grounding terminal of the equipment, and if a plug is provided, it shall be connected to the safety grounding terminal of the plug.
c. Equipment with a mains power connector shall ensure that the connector contains a safety grounding contact, which shall be the main part of the connector.
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When inserting the connector, the safety grounding shall be connected before power is supplied: when unplugging the connector, the safety grounding shall be disconnected after the power supply is interrupted.
The safety grounding terminal and the safety grounding contact shall not be used for other purposes. 8.1.2 Safety grounding connection
a. Safety grounding connection shall not be made by relying on conductive housing or frame. A separate low-impedance conductor should be used as the grounding connection to ensure that the accessible parts are electrically safe under normal use conditions and fault conditions. b. The safety grounding wire should not be used for other purposes. 8.2 Enclosed areas
To prevent personnel from entering enclosed areas with dangerous voltages, safety devices should be installed. The requirements are given in 8.2.1 below (the definitions of enclosed areas and safety devices are given in 3.6 and 3.7). 8.2.1. Enclosed area safety devices
. It should not be possible to open the access door and remove the covers, protective covers, etc. that are manually installed and removed before all dangerous voltages are removed and the accessible parts meet the electrical safety requirements. In addition, it is recommended that all parts with a peak voltage to ground exceeding 1000V must be grounded with a safety grounding switch before the access door can be opened or the covers, etc. can be removed.
b. The safety protection of personnel should be completed by safety devices that are part of the equipment. The design of the safety system should ensure that the safety of personnel not only depends on the reliable operation of relays, contactors, circuit breakers (electric, hydraulic or pneumatic), etc., but also on the mechanical aspects of the safety device (see 8.3). c. The interlock between the safety mechanism and the locking device of the access to the closed area should ensure that personnel cannot enter the closed area before the safety mechanism is properly operated. For this purpose, an appropriate mechanical system is usually required. d. The dangerous voltage cannot be reapplied before the safety grounding switch is disconnected from the ground and all access doors are closed and the covers are reset.
e. The safety system with access door equipment for entering the closed area should have a device that allows personnel to enter the closed area, but should prevent the door from being closed when the personnel are in the closed area. 8.2.2 Residual voltage on the equipment
a. The parts that become accessible after the access door of the closed area is opened and the covers, protective covers, etc. are removed should comply with the electrical safety requirements defined in 3.1.
b. The voltage on the equipment, in addition to the provisions in 3.1a, is not allowed to meet the requirements in 3.1b as long as it is inaccessible and the peak voltage to ground measured by an instrument with an internal resistance of not less than 10ka/V is less than 354V. A special protective cover that cannot be removed manually should be used to prevent personnel from approaching unsafe voltages. The protective cover should have a warning mark that meets the requirements of 5.1.2.
8.2.3 Additional measures
a. Grounding rods should be used as additional safety measures as much as possible. The grounding rod should have an insulated handle, and the insulation level of the handle should be adapted to the voltage to be contacted. There is a rigid conductive hook at one end of the handle, and the conductive hook is clearly grounded with a soft wire of appropriate cross-section. If there is insulation on this soft wire, the insulation should be transparent and loosely fitted on the conductor. Insulating beads can also be used instead.
b. The design of the equipment should ensure that there will be no electric shock when touching the surface of insulating materials outside the equipment (such as ungrounded instrument observation windows, loading and unloading parts, etc.).
Check by conducting a voltage test according to Article 3.1.
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8.3 Mechanical properties of safety devices
a.The design of the safety device should comply with the principle of "fail-safe", that is, in case of a failure inside the safety device, it can still provide protection for personnel.
b. False safety indications are not allowed.
c. The conversion of the safety device from the "safe" to the "unsafe" position must be carried out under accurate operation. And the "safe" position and the "unsafe" position cannot be confused. d. The safety device should not be manually disabled. e. The design of the safety device should withstand possible incorrect operations during use and remain effective throughout the life of the equipment.
The structure and installation of the safety earthing switch should allow personnel to directly see the connection of the contact at the installation position. f
g. Handles, knobs, etc. that are part of the safety system should be securely fixed on their shafts. Mechanical transmission devices should adopt reliable methods (such as keys, safety fixing pins, etc.) to prevent slipping or incorrect positioning. h. All components of the safety system (including mechanical connectors, bearings, conical pins, etc.) should be easy to inspect and repair. 8.4 Wiring
. The wires and cables selected for the equipment should have good insulation strength and high temperature resistance. Under the conditions of the operating voltage, temperature, humidity, atmospheric pressure, condensation, service life, pollution, etc. specified by the equipment, they should not be broken down by voltage. b. All wires and cables should be properly protected to prevent possible mechanical damage under normal working conditions.
c. The wires used for monitoring, keying, control or modulation inside the equipment and the wires connected to the external circuit should take sufficient insulation measures, preferably using structural isolation or grounding shielding to prevent contact with other wires inside the equipment. d. The end connection of the flexible cable should ensure that all electrical connections are free of mechanical stress and the cable is not worn. 8.5 Insulation
a. Where the creepage distance in the equipment is less than that specified in Appendix A (Supplement), the insulating material used must be free of leakage traces and non-flammable. For materials other than ceramics, the comparative tracking index should be determined using the test method given in GB4207. If the comparative tracking index is equal to or greater than 175, the insulating material can be considered to have no leakage traces. The flammability of insulating materials shall be tested using the test method given in GB5169. b. As long as hot cathode electron tubes, pins and sockets, relays, plugs and sockets, printed boards, transistors, micro-components and small devices comply with their respective technical specifications, they are allowed to have smaller creepage distances inside. 8.6 Voltage at RF output terminal
a. Non-electrically safe RF output terminals on transmitters, especially open feeder connectors, are allowed to exist as long as it is impossible for personnel to accidentally approach these dangerous parts. Protection or shielding should be provided where necessary. b. The RF output circuit should be designed to discharge any charge (for example, due to the accumulation of static charge that may cause dangerous voltage) to the ground as far as possible.
c. Due to coupling from other transmitters in the same workplace, there may be high voltage at the output of the transmitter. Measures should be taken to make the affected parts electrically safe. 9 High temperature, fire and other hazards
9.1 Overview
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The purpose of this chapter is to ensure that operators are not easily harmed by hot parts during normal operation, and to ensure that high temperature conditions that may cause fire or other hazards do not occur. This chapter also includes some other hazards that must be avoided in the design of equipment. 9.2 High temperature
9.2.1 Permissible temperature rise under normal use conditions No accessible part of the equipment should reach a temperature that may harm personnel, and no part should reach a temperature that may damage electrical insulation or reduce mechanical strength.
For detailed provisions on the maximum safe temperature rise under normal use conditions, see GB8898. 9.2.2 Temperature rise under fault conditions
Under fault conditions, no part of the equipment should reach a temperature that may cause fire or release flammable or harmful gases.
Use the following test methods to check;
a. If the temperature rise is limited by thermal release, overload tripping, or fuse, the temperature measurement should be carried out within 2 minutes after the device is put into operation.
If the above device is not equipped, the temperature should be measured continuously until the maximum temperature is reached, but the maximum working time of the equipment shall not exceed 6 hours.
c. Compare the measured temperature value with the maximum safe working temperature value of the parts and materials used. For the maximum temperature rise under fault conditions, see GB8898.
9.3 Fire
9.3.1 The design of the equipment should avoid the use of flammable components and materials (for example, non-flame retardant plastics) as much as possible to minimize the possibility of fire and fire spread.
9.3.2 When it is unavoidable to use components containing flammable liquids, measures should be taken to contain the leaked liquid and prevent the leaked liquid from contacting components that may reach a temperature close to the ignition point of the liquid, or prevent the insulation of the components from being damaged by the leaked liquid. 9.4 Explosion
9.4.1 General requirements
In the design of equipment, explosive components should be avoided as much as possible. Explosive components used in the equipment should be protected to avoid harm to personnel.
9.4.2 Explosion
Components that may cause harm due to explosion should be equipped with safety valves or have an "explosive structure" that releases energy to prevent excessive pressure.
The location of the safety valve or "explosive structure" should ensure that its operation will not cause harm to personnel. 9.5 Radiation
9.5.1 Requirements
The structure of the transmitting equipment should ensure that any stray or non-ionizing radio frequency radiation generated by it will not cause harm to personnel. At a distance of 10 cm from the equipment, the field quantity parameters of any stray electromagnetic radiation field generated by the transmitting equipment should meet the requirements of Table 3. 8
Frequency range
30~3000
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Electromagnetic radiation limit value
Electric field strength
150/hall
Note: f in the table represents the frequency value in MHz. 9.5.2 Monitoring
Magnetic field strength
Power density
When the operating frequency of the electromagnetic radiator is lower than 300MHz, the electric field strength and magnetic field strength should be measured separately. When the operating frequency of the electromagnetic radiator is higher than 300MHz, only the electric field strength can be measured. b. The measuring instrument should try to use a field strength meter or leakage energy meter with an omnidirectional probe. When using a non-omnidirectional probe, the probe direction must be continuously adjusted during the measurement until the maximum field strength value is measured. The instrument frequency response unevenness and accuracy should not be worse than ±3dB. 9.6 Hazardous materials
All hazardous materials used in the equipment should be listed in the equipment instructions, with detailed instructions on the safe handling, storage and disposal of these materials, and the hazards of the materials contained in the components should be pointed out at the same time. 9.7 Hazardous short circuits of low-voltage power supplies
When the equipment contains high-current low-voltage components (such as large-capacity battery packs), although its wires and connecting terminals are electrically safe according to Article 3.1, if a short circuit occurs suddenly, it is easy to cause serious arcing or overheating, causing fire and even causing harm to personnel. Therefore, the design of the equipment should minimize the possibility of such dangerous short circuits. 9.8 Safety of abnormal power supply procedures
9.8.1 When the power supply is turned on or off, even when the power supply switch is in the "on" position, no harm should be caused to personnel. 9.8.2 Protection against reverse polarity of power supply
When the power supply polarity is reversed, no harm should be caused to personnel. 9
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Appendix A
Clearance and creepage distance
(Supplement)
There should be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
72The wires and cables selected for the equipment should have good insulation strength and high temperature resistance. Under the conditions of the working voltage, temperature, humidity, atmospheric pressure, condensation, service life, pollution, etc. specified by the equipment, they should not be broken down by voltage. b. All wires and cables should be properly protected to prevent possible mechanical damage under normal working conditions.
c. The wires used for monitoring, keying, control or modulation inside the equipment and the wires connected to the external circuit should take adequate insulation measures, preferably structural isolation or grounding shielding to prevent contact with other wires inside the equipment. d. The end connection of the flexible cable should ensure that all electrical connections are free of mechanical stress and the cable is not worn. 8.5 Insulation
a. Where the creepage distance in the equipment is less than that specified in Appendix A (Supplement), the insulating material used must be free of leakage traces and non-flammable. For materials other than ceramics, the comparative tracking index should be determined by the test method given in GB4207. If the comparative tracking index is equal to or greater than 175, the insulating material can be considered to be free of leakage traces. The flammability of insulating materials shall be tested using the test methods given in GB5169. b. As long as hot cathode electron tubes, pins and sockets, relays, plugs and sockets, printed boards, transistors, micro-components and small devices comply with their respective technical specifications, smaller creepage distances are permitted inside them. 8.6 Voltage at RF output terminal
a. Non-electrically safe RF output terminals on transmitters, especially open feeder connectors, are permitted as long as it is impossible for personnel to approach these dangerous parts unintentionally, and protection or shielding shall be provided where necessary. b. As far as possible, the RF output circuit shall be designed to discharge any charge (for example, due to accumulation of static charge that may cause dangerous voltage) to the ground.
c. Due to coupling from other transmitters in the same workplace, high voltage may exist at the output of the transmitter. Measures shall be taken to make the affected components electrically safe. 9 High temperature, fire and other hazards
9.1 Overview
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The purpose of this chapter is to ensure that operators are not easily harmed by hot parts during normal operation, and to ensure that high temperature conditions that may cause fire or other hazards do not occur. This chapter also includes some other hazards that must be avoided in the design of equipment. 9.2 High temperature
9.2.1 Permissible temperature rise under normal use conditions No accessible part of the equipment should reach a temperature that may harm personnel, and no part should reach a temperature that may damage electrical insulation or reduce mechanical strength.
For detailed provisions on the maximum safe temperature rise under normal use conditions, see GB8898. 9.2.2 Temperature rise under fault conditions
Under fault conditions, no part of the equipment should reach a temperature that may cause fire or release flammable or harmful gases.
Use the following test methods to check;
a. If the temperature rise is limited by thermal release, overload tripping, or fuse, the temperature measurement should be carried out within 2 minutes after the device is put into operation.
If the above device is not equipped, the temperature should be measured continuously until the maximum temperature is reached, but the maximum working time of the equipment shall not exceed 6 hours.
c. Compare the measured temperature value with the maximum safe working temperature value of the parts and materials used. For the maximum temperature rise under fault conditions, see GB8898.
9.3 Fire
9.3.1 The design of the equipment should avoid the use of flammable components and materials (for example, non-flame retardant plastics) as much as possible to minimize the possibility of fire and fire spread.
9.3.2 When it is unavoidable to use components containing flammable liquids, measures should be taken to contain the leaked liquid and prevent the leaked liquid from contacting components that may reach a temperature close to the ignition point of the liquid, or prevent the insulation of the components from being damaged by the leaked liquid. 9.4 Explosion
9.4.1 General requirements
In the design of equipment, explosive components should be avoided as much as possible. Explosive components used in the equipment should be protected to avoid harm to personnel.
9.4.2 Explosion
Components that may cause harm due to explosion should be equipped with safety valves or have an "explosive structure" that releases energy to prevent excessive pressure.
The location of the safety valve or "explosive structure" should ensure that its operation will not cause harm to personnel. 9.5 Radiation
9.5.1 Requirements
The structure of the transmitting equipment should ensure that any stray or non-ionizing radio frequency radiation generated by it will not cause harm to personnel. At a distance of 10 cm from the equipment, the field quantity parameters of any stray electromagnetic radiation field generated by the transmitting equipment should meet the requirements of Table 3. 8
Frequency range
30~3000
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Electromagnetic radiation limit value
Electric field strength
150/hall
Note: f in the table represents the frequency value in MHz. 9.5.2 Monitoring
Magnetic field strength
Power density
When the operating frequency of the electromagnetic radiator is lower than 300MHz, the electric field strength and magnetic field strength should be measured separately. When the operating frequency of the electromagnetic radiator is higher than 300MHz, only the electric field strength can be measured. b. The measuring instrument should try to use a field strength meter or leakage energy meter with an omnidirectional probe. When using a non-omnidirectional probe, the probe direction must be continuously adjusted during the measurement until the maximum field strength value is measured. The instrument frequency response unevenness and accuracy should not be worse than ±3dB. 9.6 Hazardous materials
All hazardous materials used in the equipment should be listed in the equipment instructions, with detailed instructions on the safe handling, storage and disposal of these materials, and the hazards of the materials contained in the components should be pointed out at the same time. 9.7 Hazardous short circuits of low-voltage power supplies
When the equipment contains high-current low-voltage components (such as large-capacity battery packs), although its wires and connecting terminals are electrically safe according to Article 3.1, if a short circuit occurs suddenly, it is easy to cause serious arcing or overheating, causing fire and even causing harm to personnel. Therefore, the design of the equipment should minimize the possibility of such dangerous short circuits. 9.8 Safety of abnormal power supply procedures
9.8.1 When the power supply is turned on or off, even when the power supply switch is in the "on" position, no harm should be caused to personnel. 9.8.2 Protection against reverse polarity of power supply
When the power supply polarity is reversed, no harm should be caused to personnel. 9
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Appendix A
Clearance and creepage distance
(Supplement)
There should be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
72The wires and cables selected for the equipment should have good insulation strength and high temperature resistance. Under the conditions of the working voltage, temperature, humidity, atmospheric pressure, condensation, service life, pollution, etc. specified by the equipment, they should not be broken down by voltage. b. All wires and cables should be properly protected to prevent possible mechanical damage under normal working conditions.
c. The wires used for monitoring, keying, control or modulation inside the equipment and the wires connected to the external circuit should take adequate insulation measures, preferably structural isolation or grounding shielding to prevent contact with other wires inside the equipment. d. The end connection of the flexible cable should ensure that all electrical connections are free of mechanical stress and the cable is not worn. 8.5 Insulation
a. Where the creepage distance in the equipment is less than that specified in Appendix A (Supplement), the insulating material used must be free of leakage traces and non-flammable. For materials other than ceramics, the comparative tracking index should be determined by the test method given in GB4207. If the comparative tracking index is equal to or greater than 175, the insulating material can be considered to be free of leakage traces. The flammability of insulating materials shall be tested using the test methods given in GB5169. b. As long as hot cathode electron tubes, pins and sockets, relays, plugs and sockets, printed boards, transistors, micro-components and small devices comply with their respective technical specifications, smaller creepage distances are permitted inside them. 8.6 Voltage at RF output terminal
a. Non-electrically safe RF output terminals on transmitters, especially open feeder connectors, are permitted as long as it is impossible for personnel to approach these dangerous parts unintentionally, and protection or shielding shall be provided where necessary. b. As far as possible, the RF output circuit shall be designed to discharge any charge (for example, due to accumulation of static charge that may cause dangerous voltage) to the ground.
c. Due to coupling from other transmitters in the same workplace, high voltage may exist at the output of the transmitter. Measures shall be taken to make the affected components electrically safe. 9 High temperature, fire and other hazards
9.1 Overview
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The purpose of this chapter is to ensure that operators are not easily harmed by hot parts during normal operation, and to ensure that high temperature conditions that may cause fire or other hazards do not occur. This chapter also includes some other hazards that must be avoided in the design of equipment. 9.2 High temperature
9.2.1 Permissible temperature rise under normal use conditions No accessible part of the equipment should reach a temperature that may harm personnel, and no part should reach a temperature that may damage electrical insulation or reduce mechanical strength.
For detailed provisions on the maximum safe temperature rise under normal use conditions, see GB8898. 9.2.2 Temperature rise under fault conditions
Under fault conditions, no part of the equipment should reach a temperature that may cause fire or release flammable or harmful gases.
Use the following test methods to check;
a. If the temperature rise is limited by thermal release, overload tripping, or fuse, the temperature measurement should be carried out within 2 minutes after the device is put into operation.
If the above device is not equipped, the temperature should be measured continuously until the maximum temperature is reached, but the maximum working time of the equipment shall not exceed 6 hours.
c. Compare the measured temperature value with the maximum safe working temperature value of the parts and materials used. For the maximum temperature rise under fault conditions, see GB8898.
9.3 Fire
9.3.1 The design of the equipment should avoid the use of flammable components and materials (for example, non-flame retardant plastics) as much as possible to minimize the possibility of fire and fire spread.
9.3.2 When it is unavoidable to use components containing flammable liquids, measures should be taken to contain the leaked liquid and prevent the leaked liquid from contacting components that may reach a temperature close to the ignition point of the liquid, or prevent the insulation of the components from being damaged by the leaked liquid. 9.4 Explosion
9.4.1 General requirements
In the design of equipment, explosive components should be avoided as much as possible. Explosive components used in the equipment should be protected to avoid harm to personnel.
9.4.2 Explosion
Components that may cause harm due to explosion should be equipped with safety valves or have an "explosive structure" that releases energy to prevent excessive pressure.
The location of the safety valve or "explosive structure" should ensure that its operation will not cause harm to personnel. 9.5 Radiation
9.5.1 Requirements
The structure of the transmitting equipment should ensure that any stray or non-ionizing radio frequency radiation generated by it will not cause harm to personnel. At a distance of 10 cm from the equipment, the field quantity parameters of any stray electromagnetic radiation field generated by the transmitting equipment should meet the requirements of Table 3. 8
Frequency range
30~3000
SJ20044--92
Electromagnetic radiation limit value
Electric field strength
150/hall
Note: f in the table represents the frequency value in MHz. 9.5.2 Monitoring
Magnetic field strength
Power density
When the operating frequency of the electromagnetic radiator is lower than 300MHz, the electric field strength and magnetic field strength should be measured separately. When the operating frequency of the electromagnetic radiator is higher than 300MHz, only the electric field strength can be measured. b. The measuring instrument should try to use a field strength meter or leakage energy meter with an omnidirectional probe. When using a non-omnidirectional probe, the probe direction must be continuously adjusted during the measurement until the maximum field strength value is measured. The instrument frequency response unevenness and accuracy should not be worse than ±3dB. 9.6 Hazardous materials
All hazardous materials used in the equipment should be listed in the equipment instructions, with detailed instructions on the safe handling, storage and disposal of these materials, and the hazards of the materials contained in the components should be pointed out at the same time. 9.7 Hazardous short circuits of low-voltage power supplies
When the equipment contains high-current low-voltage components (such as large-capacity battery packs), although its wires and connecting terminals are electrically safe according to Article 3.1, if a short circuit occurs suddenly, it is easy to cause serious arcing or overheating, causing fire and even causing harm to personnel. Therefore, the design of the equipment should minimize the possibility of such dangerous short circuits. 9.8 Safety of abnormal power supply procedures
9.8.1 When the power supply is turned on or off, even when the power supply switch is in the "on" position, no harm should be caused to personnel. 9.8.2 Protection against reverse polarity of power supply
When the power supply polarity is reversed, no harm should be caused to personnel. 9
SJ20044-92
Appendix A
Clearance and creepage distance
(Supplement)
There should be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
721 Overview
SJ20044-92
The purpose of this chapter is to ensure that operators are not easily harmed by hot parts during normal operation, and to ensure that high temperature conditions that may cause fire or other hazards do not occur. This chapter also includes some other hazards that must be avoided in the design of equipment. 9.2 High temperature
9.2.1 Permissible temperature rise under normal use conditions No accessible part of the equipment should reach a temperature that may harm personnel, and no part should reach a temperature that may damage electrical insulation or reduce mechanical strength.
For detailed provisions on the maximum safe temperature rise under normal use conditions, see GB8898. 9.2.2 Temperature rise under fault conditions
Under fault conditions, no part of the equipment should reach a temperature that may cause fire or release flammable and harmful gases.
Check with the following test methods;
a. If the temperature rise is limited by thermal tripping, overload tripping, or fuse, the temperature measurement should be carried out within 2 minutes after the device is put into operation.
If the above device is not equipped, the temperature should be measured continuously until the maximum temperature is reached, but the maximum working time of the equipment shall not exceed 6h.
c. Compare the measured temperature value with the maximum safe working temperature value of the parts and materials used. The maximum temperature rise under fault conditions is shown in GB8898.
9.3 Fire
9.3.1 The design of the equipment should avoid the use of flammable components and materials (for example, non-flame retardant plastics) as much as possible to minimize the possibility of fire and fire spread.
9.3.2 When it is unavoidable to use components containing flammable liquids, measures should be taken to contain the leaked liquid and prevent the leaked liquid from contacting components that may reach a temperature close to the ignition point of the liquid, or prevent the insulation of the components from being damaged by the leaked liquid. 9.4 Explosion
9.4.1 General requirements
In the design of the equipment, explosive components should be avoided as much as possible, and protective measures should be taken for the explosive components used in the equipment to avoid harm to personnel.
9.4.2 Explosion
Components that may cause harm due to explosion shall be equipped with safety valves or have an "explosive structure" that releases energy to prevent excessive pressure.
The safety valve or "explosive structure" shall be located in a position that ensures that its operation will not cause harm to personnel. 9.5 Radiation of Animals
9.5.1 Requirements
The structure of the transmitting equipment shall ensure that any stray or non-ionizing radio frequency radiation generated by the chassis will not cause harm to personnel. At a distance of 10 cm from the equipment, the field quantity parameters of any stray electromagnetic radiation field generated by the transmitting equipment shall meet the requirements of Table 3. 8
Frequency range
30~3000
SJ20044--92
Electromagnetic radiation limit value
Electric field strength
150/hall
Note: f in the table represents the frequency value in MHz. 9.5.2 Monitoring
Magnetic field strength
Power density
When the operating frequency of the electromagnetic radiator is lower than 300MHz, the electric field strength and magnetic field strength should be measured separately. When the operating frequency of the electromagnetic radiator is higher than 300MHz, only the electric field strength can be measured. b. The measuring instrument should try to use a field strength meter or leakage energy meter with an omnidirectional probe. When using a non-omnidirectional probe, the probe direction must be continuously adjusted during the measurement until the maximum field strength value is measured. The instrument frequency response unevenness and accuracy should not be worse than ±3dB. 9.6 Hazardous materials
All hazardous materials used in the equipment should be listed in the equipment instructions, with detailed instructions on the safe handling, storage and disposal of these materials, and the hazards of the materials contained in the components should be pointed out at the same time. 9.7 Hazardous short circuits of low-voltage power supplies
When the equipment contains high-current low-voltage components (such as large-capacity battery packs), although its wires and connecting terminals are electrically safe according to Article 3.1, if a short circuit occurs suddenly, it is easy to cause serious arcing or overheating, causing fire and even causing harm to personnel. Therefore, the design of the equipment should minimize the possibility of such dangerous short circuits. 9.8 Safety of abnormal power supply procedures
9.8.1 When the power supply is turned on or off, even when the power supply switch is in the "on" position, no harm should be caused to personnel. 9.8.2 Protection against reverse polarity of power supply
When the power supply polarity is reversed, no harm should be caused to personnel. 9
SJ20044-92
Appendix A
Clearance and creepage distance
(Supplement)
There should be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
721 Overview
SJ20044-92
The purpose of this chapter is to ensure that operators are not easily harmed by hot parts during normal operation, and to ensure that high temperature conditions that may cause fire or other hazards do not occur. This chapter also includes some other hazards that must be avoided in the design of equipment. 9.2 High temperature
9.2.1 Permissible temperature rise under normal use conditions No accessible part of the equipment should reach a temperature that may harm personnel, and no part should reach a temperature that may damage electrical insulation or reduce mechanical strength.
For detailed provisions on the maximum safe temperature rise under normal use conditions, see GB8898. 9.2.2 Temperature rise under fault conditions
Under fault conditions, no part of the equipment should reach a temperature that may cause fire or release flammable and harmful gases.
Check with the following test methods;
a. If the temperature rise is limited by thermal tripping, overload tripping, or fuse, the temperature measurement should be carried out within 2 minutes after the device is put into operation.
If the above device is not equipped, the temperature should be measured continuously until the maximum temperature is reached, but the maximum working time of the equipment shall not exceed 6h.
c. Compare the measured temperature value with the maximum safe working temperature value of the parts and materials used. The maximum temperature rise under fault conditions is shown in GB8898.
9.3 Fire
9.3.1 The design of the equipment should avoid the use of flammable components and materials (for example, non-flame retardant plastics) as much as possible to minimize the possibility of fire and fire spread.
9.3.2 When it is unavoidable to use components containing flammable liquids, measures should be taken to contain the leaked liquid and prevent the leaked liquid from contacting components that may reach a temperature close to the ignition point of the liquid, or prevent the insulation of the components from being damaged by the leaked liquid. 9.4 Explosion
9.4.1 General requirements
In the design of the equipment, explosive components should be avoided as much as possible, and protective measures should be taken for the explosive components used in the equipment to avoid harm to personnel.
9.4.2 Explosion
Components that may cause harm due to explosion shall be equipped with safety valves or have an "explosive structure" that releases energy to prevent excessive pressure.
The safety valve or "explosive structure" shall be located in a position that ensures that its operation will not cause harm to personnel. 9.5 Radiation of Animals
9.5.1 Requirements
The structure of the transmitting equipment shall ensure that any stray or non-ionizing radio frequency radiation generated by the chassis will not cause harm to personnel. At a distance of 10 cm from the equipment, the field quantity parameters of any stray electromagnetic radiation field generated by the transmitting equipment shall meet the requirements of Table 3. 8
Frequency range
30~3000
SJ20044--92
Electromagnetic radiation limit value
Electric field strength
150/hall
Note: f in the table represents the frequency value in MHz. 9.5.2 Monitoring
Magnetic field strength
Power density
When the operating frequency of the electromagnetic radiator is lower than 300MHz, the electric field strength and magnetic field strength should be measured separately. When the operating frequency of the electromagnetic radiator is higher than 300MHz, only the electric field strength can be measured. b. The measuring instrument should try to use a field strength meter or leakage energy meter with an omnidirectional probe. When using a non-omnidirectional probe, the probe direction must be continuously adjusted during the measurement until the maximum field strength value is measured. The instrument frequency response unevenness and accuracy should not be worse than ±3dB. 9.6 Hazardous materials
All hazardous materials used in the equipment should be listed in the equipment instructions, with detailed instructions on the safe handling, storage and disposal of these materials, and the hazards of the materials contained in the components should be pointed out at the same time. 9.7 Hazardous short circuits of low-voltage power supplies
When the equipment contains high-current low-voltage components (such as large-capacity battery packs), although its wires and connecting terminals are electrically safe according to Article 3.1, if a short circuit occurs suddenly, it is easy to cause serious arcing or overheating, causing fire and even causing harm to personnel. Therefore, the design of the equipment should minimize the possibility of such dangerous short circuits. 9.8 Safety of abnormal power supply procedures
9.8.1 When the power supply is turned on or off, even when the power supply switch is in the "on" position, no harm should be caused to personnel. 9.8.2 Protection against reverse polarity of power supply
When the power supply polarity is reversed, no harm should be caused to personnel. 9
SJ20044-92
Appendix A
Clearance and creepage distance
(Supplement)
There should be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
722 Protection against reverse polarity of power supply
When the polarity of power supply is reversed, it shall not cause harm to personnel. 9
SJ20044-92
Appendix A
Clearance and creepage distance
(Supplement)
There shall be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
722 Protection against reverse polarity of power supply
When the polarity of power supply is reversed, it shall not cause harm to personnel. 9
SJ20044-92
Appendix A
Clearance and creepage distance
(Supplement)
There shall be appropriate clearance and creepage distance between conductive parts to avoid failure under dust deposition or humid conditions. The clearance and creepage distance given in Table A1 are the minimum practical clearances for design assembly and part tolerances. DC or peak voltage
72
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