Standards series for electrical installations under severe outdoor conditions (GB/T 9089.1 - 2008 to 9089.5 - 2008)
This series of standards targets electrical facilities in outdoor, semi - outdoor, and harsh - climate areas (such as scenarios with high temperature, high humidity, corrosion, mechanical impact, etc.), and systematically standardizes safety and reliability requirements.Part 1 "Scope and Definitions" clarifies the applicable boundaries of the standard, covering the entire chain from equipment to devices. It also defines core terms such as "severe conditions" (referring to the combination of extreme factors beyond the normal indoor environment) and "protection levels" (such as the dust - and water - proof capabilities indicated by the IP code), providing a unified context for the subsequent content.Part 2 "General Protection Requirements" focuses on basic protection, stipulating that the enclosure must meet the dust - and splash - proof level of IP65 or above, and the materials must have the ability to resist UV aging (e.g., by adding UV stabilizers) and corrosion (e.g., through galvanizing or powder coating).Part 3 "General Requirements for Equipment and Accessories" is targeted at the equipment itself. It requires that the enclosure material be made of ABS engineering plastic with strong weather resistance or stainless steel, and the connection points of accessories must use rubber gaskets for waterproof sealing.Part 4 "Device Requirements" focuses on the overall installation layout, specifying that the wiring must pass through waterproof conduits, and the equipment spacing must meet the requirements for heat dissipation (spacing ≥ 50mm) and maintenance (passage width ≥ 1m).Part 5 "Operation Requirements" emphasizes operation management, stipulating that insulation resistance testing (resistance value ≥ 0.5MΩ) should be conducted at least once a month, and the equipment should be shut down and the power supply cut off before extreme weather such as typhoons and heavy rains.
Standard series of rubber-insulated cables with rated voltage of 450/750V and below (GB 5013.1 - 1997 to 5013.7 - 1997)
This series formulates rules covering all dimensions of "materials - structure - performance - application" for rubber-insulated cables. Part I "General requirements" serves as a general framework, stipulating that the cable structure shall include an annealed copper wire conductor (single - wire diameter ≤0.4mm), a rubber insulation layer (thickness ≥0.8mm) and a sheath (if required). The materials shall meet the requirements of oil resistance (weight change ≤5% after 24 - hour immersion) and aging resistance (insulation resistance decrease ≤30% after 7 days at 100℃), and the rated voltage, model and manufacturer information shall be clearly printed on the cable surface. Part II "Test methods" clarifies the verification means. For example, the DC resistance of the conductor is tested with a double - bridge (error ≤0.5%), the insulation resistance is tested with a 500V megohmmeter (resistance ≥100MΩ·km), and the voltage - withstand test requires applying a 2000V voltage for 1 minute without breakdown. Part III "Heat - resistant silicone rubber - insulated cables" is for high - temperature scenarios (such as near industrial furnaces), requiring a long - term operating temperature ≥180℃ and a short - circuit temperature ≥350℃. Part IV "Flexible cords and flexible cables" is suitable for flexible applications (such as mobile sockets and power cords of household appliances), stipulating a bending radius ≤6 times the cable outer diameter and bending fatigue resistance ≥10,000 cycles (no breakage or insulation cracking). Part V "Elevator cables" is for the dynamic scenario of frequent start - stop of elevators, requiring a tensile strength ≥1000N and bending resistance ≥50,000 times (bending radius: 10 times the cable outer diameter). Part VI "Welding machine cables" meet the high - current requirements (such as welding operations), stipulating a conductor cross - sectional area ≥16mm² and a voltage drop ≤5mV/m (at 20℃). Part VII "Heat - resistant ethylene - vinyl acetate rubber - insulated cables" balance heat resistance and flexibility, with a long - term operating temperature ≥90℃ and no cracks in low - temperature bending (-15℃×4 hours).
Standard series of polyvinyl chloride insulated cables with rated voltage of 450/750V and below (GB 5023.1 - 1997 to 5023.7 - 1997)
This series focuses on the characteristics of polyvinyl chloride (PVC) insulated cables (low cost, easy to process but with limited heat resistance) and specifically regulates the application requirements.Part I "General Requirements" stipulates that the cable structure is copper conductor + PVC insulation + PVC sheath (if required). The PVC material shall meet the requirements of oxygen index ≥ 30 (flame retardant) and tensile strength ≥ 12 MPa (sheath).Part II "Test Methods" corresponds to performance verification. For example, the insulation thickness is tested with a micrometer (error ≤ 0.01 mm), and the sheath tear strength is tested with a tensile testing machine (≥ 5 N).Part III "Non - sheathed cables for fixed wiring" is used in fixed scenarios such as inside walls and suspended ceilings. It requires that the deviation of the conductor outer diameter ≤ ±0.05 mm and the insulation withstand voltage ≥ 1500 V.Part IV "Sheathed cables for fixed wiring" adds sheath protection. It requires that the sheath thickness ≥ 1.0 mm and it should be puncture - resistant (not penetrated when a 5 N force is applied with a 2 mm - diameter steel needle).Part V "Flexible cables (flexible cords)" is for household appliances. It requires that the bending radius ≤ 4 times the cable outer diameter and it should be oil - resistant (volume change ≤ 10% after 24 - hour immersion).Part VI "Elevator cables and cables for flexible connections" is suitable for dynamic equipment such as elevators and robots. It requires that the number of bending cycles ≥ 30,000 times and the tensile strength ≥ 800 N.Part VII "Two - core or multi - core shielded and unshielded flexible cables" is for electromagnetic - sensitive scenarios (such as instruments and equipment). It requires that the shielding layer coverage rate ≥ 90% and the anti - interference attenuation ≥ 40 dB (at 100 MHz).
Environmental test standards series for electrical and electronic products (GB/T 2421 - 1999, GB/T 2423.1 - 2001, etc.)
This series verifies the environmental adaptability of products through the "simulated environment - test method - result evaluation" system. GB/T 2421 - 1999 "General rules" clarifies the test purpose - to evaluate the functional stability of products in expected environments (such as transportation, use, and storage). Environmental factors are divided into three categories: climatic (temperature, humidity), mechanical (vibration, impact), and chemical (salt spray, corrosion). It also stipulates that products need to be pre - treated before the test (e.g., placed at room temperature for 24 hours).GB/T 2423.1 - 2001 "Test A: Low temperature" simulates a cold environment. It requires a test temperature of - 40°C (adjustable as needed) and a duration of 24 hours. After the test, the product should be able to start normally.GB/T 2423.3 - 1993 "Test Ca: Damp heat, steady state" simulates a high - humidity environment (such as the plum - rain season in the south). The temperature is set at 40°C, the humidity at 93%RH, and the duration is 48 hours. After the test, the insulation resistance should be ≥ 50% of the initial value.GB/T 2423.6 - 1995 "Test Eb: Bump" simulates transportation collisions. The acceleration is 100m/s², and the number of bumps is 1000 times (500 times in each of the positive and negative directions). After the test, the structure should be free of looseness and the function should be normal.GB/T 2423.8 - 1995 "Test Ed: Free fall" is for handheld devices (such as mobile phones). The drop height is 1m, and the number of drops is 10 times (2 times on each different surface). The shell should be free of cracks and the screen should be undamaged.GB/T 2423.10 - 1995 "Test Pc: Vibration (sinusoidal)" simulates a vibration environment (such as automotive transportation). The frequency ranges from 5 - 500Hz, the acceleration is 20m/s², and the duration is 2 hours. After the test, no components should fall off.GB/T 2423.22 - 2002 "Test N: Temperature change" simulates alternating high - and low - temperature environments (such as areas with large diurnal temperature differences). The temperature ranges from - 20°C to 85°C with 5 cycles (1 hour per cycle), to evaluate the influence of thermal expansion and contraction of materials on the structure.GB/T 2423.28 - 1982 "Test T: Soldering test" verifies the heat resistance of soldering. The soldering temperature is 260°C and the time is 3 seconds. After the test, there should be no desoldering at the solder joints and no damage to the components.GB/T 2423.43 - 1995 "Guidelines for the mounting of specimens for dynamic tests" standardizes the fixing method during the test. It requires the use of special fixtures to simulate the actual installation state and ensure uniform load transfer to the product.
Standard series for fire hazard tests for electric and electronic products (GB/T 5169.5 - 1997, 5169.10 - 1997, etc.)
This series focuses on the fire risks of "ignition - combustion - spread" and evaluates the flame - retardant performance of products by simulating small - energy ignition sources. GB/T 5169.5 "Needle - flame test" simulates tiny flames (such as those from lighters or electrical short - circuit sparks). It uses a needle - shaped flame with a diameter of 0.9 mm and a length of 35 mm (temperature: 750℃ ± 50℃) and aims it at the weak parts of the sample (such as the gaps in the casing) for 30 seconds. The sample is required not to ignite the surrounding combustibles (such as the filter paper 20 mm below). GB/T 5169.10 "General rules for glow - wire tests" stipulates the general rules. The glow - wire is made of nickel - chromium alloy wire (diameter: 4 mm), with a temperature range of 750 - 960℃ (selected according to the material category) and an applied pressure of 1 N ± 0.2 N. The test should be carried out in an environment without wind and at room temperature (20℃ ± 5℃). GB/T 5169.11 "Glow - wire test for finished products" is for final products (such as household appliance casings and sockets). The glow - wire should be in contact with the sample for 30 seconds and then removed. The sample should extinguish within 30 seconds and no dripping matter should ignite the filter paper. GB/T 5169.12 "Glow - wire flammability test for materials" is for raw materials (such as plastic granules and rubber sheets). It tests the "glow - wire ignition temperature" (the lowest temperature of the glow - wire at which the material can burn continuously) and the "glow - wire burning time" (the time during which the material continues to burn after the glow - wire is removed). For example, the ignition temperature of ABS plastic should be ≥ 850℃ and the burning time should be ≤ 30 seconds.
Limit and fit standard series (GB/T 1800.1 - 1997 to 1800.3 - 1998, etc.)
This series constructs a dimensional control framework of "basic terms - tolerance system - application guidance", which is the "language" of mechanical design and manufacturing. The GB/T 1800 series is the core:I. Part 1 "Vocabulary" defines key concepts:- "Tolerance" refers to the allowable variation range of dimensions (for example, the tolerance of a dimension of 10mm ± 0.015mm is 0.03mm).- "Deviation" refers to the difference between the actual dimension and the basic dimension (for example, the upper deviation of an actual dimension of 10.01mm is +0.01mm).- "Fit" refers to the dimensional relationship between a hole and a shaft (clearance fit: hole < shaft).ii. part 2 "basic provisions" clarifies the composition of the tolerance zone, which consists of:- "standard tolerance" (from it01 to it18, with it01 having the highest accuracy and the smallest tolerance).- "fundamental deviation" (which determines the position of the tolerance zone relative to the basic dimension. holes are represented by capital letters h/h, and shafts are represented by lowercase letters g/g).iii. part 3 "numerical tables" provides specific tolerance values. for example, the tolerance of a size of 10mm at it7 level is 0.015mm. the lower deviation of an h7 hole is 0, and the upper deviation is +0.015mm. the upper deviation of an h6 shaft is 0, and the lower deviation is -0.009mm.gb/t 1801 - 1999 "selection of tolerance zones and fits" guides applications. for example, a clearance fit (h7/g6) is used for parts that need to rotate (such as the inner ring of a bearing and the shaft), a transition fit (h7/h6) is used for parts that need to be positioned (such as a gear and the shaft), and an interference fit (h7/u6) is used for parts that transmit torque (such as a pulley and the shaft).gb/t 1803 - 2003 "tolerance zones for holes and shafts up to 18mm in size" is for small - sized parts (such as precision screws and bearings), listing the specific tolerance values of common fits such as h7/g6 and h7/h6.gb/t 1804 - 2000 "general tolerances" specifies the tolerance grades for unmarked dimensions. for example, the unmarked tolerance for linear dimensions is it14 level (the tolerance is ±0.2mm when the size ≤ 30mm), and the unmarked tolerance for angular dimensions is ±1°.gb/t 1167 - 1996 "transition - fit threads" is used for the positioning fit between bolts and nuts (such as the fixing of equipment bases), specifying the thread tolerance zone as 6h/6g (hole 6h, shaft 6g).gb/t 1181 - 1998 "interference - fit threads" is used for set screws (such as fixing gears on a shaft), requiring an interference amount of 0.01 - 0.03mm for the thread pitch diameter to ensure that the screw does not loosen after being screwed in.gb/t 1182 - 1996 "geometric tolerances" specifies the symbols and marking methods for geometric tolerances. for example, roundness is represented by "○", and coaxiality is represented by "◎". the tolerance frame should be marked on the dimension line or the datum line.gb/t 1184 - 1996 "unspecified geometric tolerance values" provides the default values for unspecified geometric tolerances. for example, the unspecified tolerance for straightness is 0.1mm/1000mm, and the unspecified tolerance for roundness is it12 level (0.025mm for a size of 10mm).