GB/T 24274-2019Low-voltage withdrawable switchgear and controlgear assemblies (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 24274-2009 "Low-voltage withdrawable switchgear and control equipment", and GB/T 24274-2009 The main technical changes are as follows.

--- Added provisions for other features (see 5.6);

--- Removed the frame size preferences (see 7.1.2 of the 2009 edition);

--- Increased requirements for lifting devices and related verification (see 8.1.5 and 10.2.4);

--- Increased requirements for mechanical collision protection and related verification (see 8.2.1 and 10.3);

--- Increased the rms rms of the test voltage between the disconnected contacts of the equipment (see Table 8.3, Table 4, Table 4.4.2, 2009);

--- Increased requirements for fixed components and related verification (see 8.5.1 and 10.6);

--- Increased baffle requirements and related verification (see 8.5.7 and 10.6);

--- Increased requirements for the selection and installation of unprotected live conductors and related verification (see 8.7.5 and 10.8);

--- Increased cooling requirements (see 8.8);

--- Revised the test voltage value of the main frequency and auxiliary circuit power frequency withstand voltage in dielectric performance (see Table 8 and Table 9 in 9.1.2, 2009) Version 7.11.3, Table 11 and Table 12);

--- Increased the protection requirements and related verification of surge protection devices (see 9.1.4 and 10.10);

--- Increased the requirements for the cooperation of protective devices (see 9.3.4);

---Modified the verification method, and revised the type test and the factory test to design verification and routine inspection (see Chapter 10, 2009 edition). Chapter 8);

--- Revised the number of times the impact withstand voltage was applied to each pole of the impact withstand voltage test, and changed it to 5 times 3 times (see 10.10, 2009 edition) 8.2.9);

--- Modified the duration of each pole applied in the selectable power frequency voltage test and DC voltage test, and modified 10ms to Between 15ms and 100ms (see 10.10, 8.2.9 of the 2009 edition);

--- Increased the temperature rise test method, based on the verification test, added verification verification, verification evaluation method (see 10.11);

--- Modified the number of operations for mechanical operation verification, and changed it to 200 times 50 times (see 10.14, 8.2.18.1 of 2009 edition).

1 Scope

This standard specifies the classification, interface characteristics, information, and information of low-voltage withdrawable switchgear and control equipment (hereinafter referred to as complete sets of equipment). Use conditions, structural and performance requirements, and verification requirements.

This standard is applicable to fixed installation under normal conditions of use in the house. The rated voltage AC does not exceed 1000V, and the DC does not exceed 1500V. Extraction-type switchgear and control equipment for power distribution and motor control.

Note: The complete set of equipment with rated working voltage AC 1140V can be implemented with reference to this standard. Requirements regarding dielectric properties, etc. are determined by the manufacturer and the user.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 762-2002 standard current level

GB/T 4025 Human Machine Interface Marker Identification Basic and Safety Rule Indicators and Encoding Rules for Operating Devices

GB/T 4026 Basic and safety rules for human-machine interface markings Identification of equipment terminals and conductor terminals

GB/T 4205 Human Machine Interface Marking Logo Basic and Safety Rules Operating Rules

GB/T 4208 enclosure protection grade (IP code)

GB/T 5169.5 Fire hazard testing for electric and electronic products - Part 5: Tests Test methods and guidelines

GB/T 7251.1-2013 Low-voltage switchgear and control equipment - Part 1: General

GB/T 7251.12-2013 Low-voltage switchgear and control equipment - Part 2: Complete sets of power switches and control equipment

GB/T 7947 Human-machine interface logo marking basic and safety rules conductor color or alphanumeric identification

GB/T 14048.1 Low-voltage switchgear and control equipment - Part 1: General

GB/T 14048.3 Low-voltage switchgear and control equipment - Part 3: Switch, isolator, isolating switch and fuse combination

GB/T 16935.1-2008 Insulation of equipment in low-voltage systems - Part 1: Principles, requirements and tests

GB/T 20138 Protection level of external mechanical collision of electrical equipment casing (IK code)

GB/T 20641 General requirements for low-voltage switchgear and control equipment

IEC 60085 Electrical insulation heat resistance assessment and design (Electricalinsulation-Thermalevaluationanddesig- Nation)

IEC 60216 (all parts) Electrical insulation materials heat resistance [Electricalinsulatingmaterials-Thermalendur- Anceproperties(alparts)]

3 Terms and definitions

The following terms and definitions as defined in GB/T 7251.1-2013 and GB/T 7251.12-2013 apply to this document.