GB 16895.3-1997 Electrical installations in buildings Part 5: Selection and installation of electrical equipment Chapter 54: Grounding arrangements and protective conductors
Some standard content:
GB16895.31997 | The first revised text was formulated, and the technical content and chapter, article, table, and figure numbers are the same as that of the publication. In order to be consistent with IEC364-5-54, the nature of the appendices of this standard is not specified. Among the cited standards listed in the introduction and text of IEC364-5-54, the ones that have been adopted as Chinese standards are: eqv IEC 79-8
GB3836.1-83 General requirements for explosion-proof electrical equipment for explosive environments GB3953- 83 Electrician round copper wire
GB3955--83 Electrician round aluminum wire
GB14821.1--93 Building electrical installation electric shock protection eqv IEC 28
eqv IEC 111||tt| |eqv IEC 364-4-41:1992
The data in the right column in the table in Appendix A is calculated and rounded based on the data in the left column. The calculation result of the third number is 41.157, which is rounded to 41, IEC364 The given value of -5-54 is 42, which will be corrected when this standard is adopted. It is divided into the following seven parts under the general title of "Electrical Installations in Buildings"; Part 1 Scope, Purpose and Basics
Definition
Part 2
Part 3| |tt||Part 4
Part 5
Part 6
General Characteristics Evaluation
Safety Protection
Selection and Installation of Electrical Equipment| |tt||Inspection
Requirements for special devices or locations
Part 7
This standard is Chapter 54 of Part 5.
This standard is proposed by the Ministry of Labor of the People's Republic of China. This standard is under the jurisdiction of the National Building Electrical Installation Standardization Technical Committee. This standard is drafted by the Machinery Standardization Institute of the Ministry of Machinery Industry. The main drafters of this standard are: Li Shilin, Guo Ting, and Feng Zongheng. This standard was first released on June 3, 1997. 36 | | tt | | GB 16895.3--1997 | Developed to express, as far as possible, an internationally consistent view on the subject matter covered. 2) These resolutions or agreements are intended for international use in the form of recommendations and are accepted by the National Committees in this sense. 3) In order to promote international consistency, IEC expresses the desire that national committees, if their national conditions permit, adopt the texts recommended by IEC in their respective national regulations. Any differences between the text of IEC recommendations and the corresponding national regulations should be clearly stated in the national regulations.
IEC Introduction
This standard was developed by IEC Technical Committee 64 (Electrical installations in buildings). The draft of this standard was discussed at the 1976 Toronto and 1977 Moscow conferences. As a result of the Moscow conference, the draft "Document 64 (Central Office) 68" was submitted to the national committees for voting in November 1977 according to the June Law. In addition, the wording of Articles 543.1, 543.1.1 and Appendix A [Document 64 (Central Office) 75] were distributed in December 1978 for voting under the "February Law".
The following national committees voted explicitly in favor of the draft June Law: Australia
Egypt
The Netherlands
Sweden
Austria
France| |tt||Norway
Switzerland
Belgium
Israel
Romania
Turkey
Bulgaria
Italy”|| tt||South Africa (Republic)
United States
The following national committees voted expressly in favor of the publication of Section 543.1, Section 543.1.1 and Appendix A: Australia
France
Poland| |tt||Switzerland
Austria
West Germany
Romania
Turkey
Other IEC standards cited in this standard:
Publications
28
79-8
111
287
364-1
364-4-41
Belgium
Israel
South Africa (Republic)
Soviet Union··
International Standard for Copper Resistance
Denmark
Italy*||tt| |Spain
United States
Canada
Japan
Spanish
Egypt
Netherlands
Sweden||tt| |Maximum surface temperature classification
Electrical equipment in explosive gas environments Chapter 8 Recommended values ??of resistivity of commercial cold-drawn aluminum conductors Calculation of rated continuous current values ??of cables (100% load factor) Electrical installations in buildings Chapter 1 Applicable Scope, Purpose and Definition Chapter 4 Safety Protection Chapter 41 Electric Shock Protection
The country changed to a fee-based vote after issuing a vote against it.
37
National Standards of the People's Republic of China
Building Electrical Installations
Part 5: Selection and Installation of Electrical Equipment Chapter 54: Grounding Configuration and Protective Conductors
Electrical installations of buiidingsPart 5: Selection and erection of electrical equipmentChapter 54: Earthing arrangements and protective conductors541 General
541.1 Grounding configuration should meet the safety and functional requirements of electrical installations 542 Ground connection
542.1 Grounding configuration| |tt||GB 16895.3—1997
idt IEC 364-5-54:1980
542.1.1 In accordance with the requirements of the electrical installation, the grounding arrangement used for protective or functional purposes may be integrated or separate. 542.1.2 Equipment in a grounding configuration shall be selected and installed so that: the ground resistance value complies with the protective and functional requirements of the electrical installation and is expected to be effective over the long term; and is capable of withstanding ground fault currents and leakage currents to earth without danger, especially from thermal , Hazards caused by thermal mechanical stress and electrical mechanical stress;
- Have sufficient strength or additional mechanical protection to adapt to the external influence of the location (see Chapter 32 of IEC364-3). 542.1.3 Protective measures shall be taken to prevent damage to other metal parts due to electrical corrosion. 542.2 Ground electrode
542.2.1 The following types of ground electrodes can be used: buried rod or tube,
buried strip or wire:
buried plate;|| tt||Ground electrode buried in the foundation:
Rebar in reinforced concrete;
Note
1 Special caution should be taken when the structure contains prestressed reinforced concrete. ....... - Metal water pipe systems complying with Article 542.2.5; - Other suitable underground components (see Article 542.2.6). 2. The effectiveness of the grounding electrode depends on the local soil conditions. It is advisable to select one or several grounding electrodes suitable for the soil conditions according to the required grounding resistance value. The grounding resistance value of the grounding electrode can be obtained by calculation or actual measurement. Practical guidelines are under consideration.
542.2.2 The type and burial depth of the ground electrode should be such that the ground resistance value of the ground electrode will not exceed the required value due to drying and freezing of the soil.
542.2.3 The material and structure of the ground electrode should be able to withstand damage caused by corrosion. Approved by the State Bureau of Technical Supervision on June 03, 1997 38 | Increase the ground resistance value of the ground electrode. 542.2.5 Metallic plumbing systems may be used as grounding electrodes only with the consent of the water supply authority and with an agreement to notify users of electrical installations in advance of any proposed changes to the plumbing system. Note: The reliability of the grounding configuration should not be guaranteed by other protocols. 542.2.6 divided by 542.2.Except for metal pipes that are only used for water supply as mentioned in Article 5, other metal pipe supply systems (such as flammable liquids or gases, heating systems, etc.) should not be used as grounding electrodes for protective purposes. Note: This requirement does not prevent other public pipelines from being equipotentially bonded in accordance with GB14821.1. 542.2.7 Only with the consent of the cable owner, and the lead sheath and other metal outer sheaths of the cable are not easily damaged due to excessive corrosion, and if there are any plans to make changes to the cable that may affect its use as a grounding electrode, the cable must be installed in advance. Cable lead sheaths and other metallic outer sheaths may be used as earth electrodes only after appropriate protocol has been notified to the user of the electrical installation. 542.3 Grounding conductor
542.3.1 The grounding conductor shall comply with the provisions of Article 543.1, and the cross-section of the grounding conductor buried in the soil shall comply with the provisions of Table 54A. NOTE: Non-circular conductor sizes are under consideration. 542.3.2 The connection between the ground conductor and the ground electrode should be reliable and have good electrical performance. Where clamping devices are used, they shall not damage the earthing electrode (e.g. pipe) or earthing conductor. 542.4 General grounding terminal or grounding bus
542.4.1 Each device shall be provided with a general grounding terminal or grounding busbar, and the following conductors shall be connected to it: Grounding conductor:
Protective conductor; ||tt ||A total equipotential bonding conductor;
Table 54A commonly used cross-sections of grounding conductors
With mechanical protection
With anti-corrosion protection
Without anti-corrosion protection
Grounding conductors for functional purposes as required by Clause 543.1
When required. Copper 25 mm*; Iron 50 mm2
without mechanical protection
steel
iron
16 mm2
16 mm
542.4. 2. The connector used to disconnect the ground conductor must be set in an accessible position. This connector can be easily combined with the main ground terminal or ground bus bar to facilitate the measurement of the ground resistance value. The connector should only be used with tools. In order to be disconnected, it should be mechanically solid, strong and able to maintain electrical continuity. 542.5 Interconnections to ground configurations of other systems 542.5.1 Systems with higher voltages than it
are under consideration.
542.5.2 lightning protection system
is under consideration.
542.5.3 Other systems
Devices such as those described in clause 1.3 of IEC364-1 are under consideration. 543 Protective conductor
Note: For equipotential bonding protective conductors, see Chapter 547. 543.1 Minimum cross-section
The cross-section of the protective conductor shall be calculated according to Article 543.1.1 of
, or selected according to Article 543.1.2 of
39
.
GB
16895.3-1997
The requirements of Article 543.1.3 should be considered in both cases above. NOTE: Equipment terminals within the electrical installation should be capable of being connected to these protective conductors. 543.1.1 The cross-section should not be smaller than the value calculated according to the following formula (only applicable when the disconnection time does not exceed 5s) S
where: -
cross-section, mm2
One stream passes through The fault current value (AC root mean square value) of the protective electrical appliance caused by a fault with negligible impedance, A; the action time of cutting off the electrical appliance, $:
Note: The current limiting effect of the loop impedance and the limit of the protective electrical appliance should be considered Pass capacity (Joule integral). A coefficient determined by the material of the protective conductor, insulation and other parts as well as the initial and final temperatures. See Appendix A for the calculation of the value.
The various table values ??of protective conductors with different purposes or usage conditions are shown in Table 54B, Table 54C, Table 54D and Table 54E. Table 54B Values ??for non-cable core insulated protective conductors or bare protective conductors in contact with cable outer sheath Insulation of protective conductors or cable outer sheath
PVC
Final temperature
Conductor material
Copper
Aluminum
Steel
160℃
143
95
52
Note: The initial temperature of the conductor is set to 30C
EPR,XLPE
250℃
TablebZxz.net
176
116
64|| tt||Butyl rubber
220℃
166
110
60
If the cross-section calculated by the formula is not a standard size, then Adjacent and larger standard sections should be used. Note 1: The cross section calculated according to this calculation must be adapted to the fault loop impedance value. Table 54C The value of one core wire used as a protective conductor in a multi-core cable. Insulating material
PVc
Initial temperature
Final temperature
Conductor material
Copper
Aluminum
Initial temperature
Final temperature
Conductor material
Steel, steel/copper
Aluminum, lead||tt| |40
70℃
160℃
115
76
XLPE,EPR
90℃
250℃
143
94
Table 54D Cable sheathing or armoring used as a protective conductor table value insulated material
PVC
160℃||tt || tt||89
butyl rubber
220℃
bar
quality
body material
guide
highest temperature
copper
maximum temperature
aluminum
maximum temperature
steel
pieces
GB16895.3-1997| |tt||Table 54K value of a bare conductor that poses no risk of endangering any adjacent materials at the following temperatures Visible and within a restricted location
500℃
228| |tt||300℃
125
500℃
82
Note: The initial temperature of the conductor is 30℃. *The temperatures listed are only valid if they do not compromise joint quality. Note
Normal conditions
200℃
159
200℃
105
200℃
58||tt ||2 For the allowable maximum surface temperature limit of devices in explosive hazardous environments, see GB3836.1. 3 The maximum allowable temperature of the connection point should be taken into account. 4Values ??for mineral insulated cables are under consideration. Fire hazard
150℃
138
150℃
91
150℃
50
543.1.2 Protection The cross-section of the conductor should not be smaller than the corresponding value in Table 54F, so there is generally no need to perform verification according to Article 543.1.1. When applying this table, if non-standard cross-section dimensions result, the conductor closest to the standard cross-section is used. The values ??in Table 54F only apply if the material of the protective conductor is in phase with the phase conductor. Otherwise, the cross-section of the protective conductor is determined so that the resulting conductance is equivalent to the conductance using the values ??listed in Table 54F. 543.1.3 The cross-section of each protective conductor other than the outer sheath of the supply cable or an integral part of the cable shall in no case be less than the following:
The cross-section of the phase conductor set out in Table 54F
s
S≤16
1635
s>35
With mechanical protection, 2.5mm;
Without mechanical protection , 4 mm2.
The phase conductor cross-section of the device and the minimum cross-section of the corresponding protective conductor The minimum cross-section of the corresponding protective conductor
Sp
s
16
S/2
Note: See also IEC 364-5-52 standard for the selection and installation of conductors and cables according to external influences. 543.2 Types of protective conductors
Note: The selection and installation of various types of protective conductors should consider the requirements of the IEC 364-5-52 standard and this standard. 543.2.1 The protective conductor may consist of the following parts: the core of a multi-core cable;
insulated conductors or bare conductors that share a sheath with live conductors; fixed number of bare or insulated conductors; a metal sheath, such as the sheath, screen and armor of some cables (further requirements are under consideration); the metal casing or other metal sheath of the conductor (further requirements are under consideration); the conductive part outside some devices.
mm2
41
GB 16895.3—1997
543.2.2 When there are factory-made complete sets of equipment or metal-enclosed busbar duct systems (busbar ducts) sheaths or frames in the device, they can be used as protective conductors if they meet the following three requirements at the same time: a) their electrical continuity should not be affected by mechanical, chemical or electrochemical corrosion; b) their conductivity should be at least equal to the result obtained by applying 543.1, c) they should be able to have a terminal at each intended branch to connect to other protective conductors. 543.2.3 The outer metal sheath of certain wiring, including sheath (bare and insulated), especially the sheath of mineral insulated cables, and certain metal casings and trunkings for electrical lines (whose types are under preparation), can be used as protective conductors for corresponding circuits if they meet the requirements of 543.2.2 a) and b).
543.2.4 The conductive parts outside the device can be used as protective conductors if they meet all the following four requirements: a) Their electrical continuity should be ensured whether from the structure or from the applicable connection, so that they are not mechanically, chemically or electrochemically damaged and corroded;
b) Their conductivity should be at least equal to the conductivity value obtained in accordance with 543.1; c) Measures should be taken to prevent them from shifting, except for compensatory measures d) When they have been considered as protective conductors, appropriate measures can be taken if necessary. The use of metal water pipes is permitted as long as the person in charge or department of the water supply and drainage system agrees, and gas pipes should not be used as protective conductors. 543.2.5 Conductive parts outside the device should not be used as PEN conductors. 543.3 Maintenance of electrical continuity of protective conductors 543.3.1 The protective conductor should be properly protected against mechanical and chemical damage and corrosion and the effects of electrodynamics. 543.3.2 The joints of the protective conductors should be easy to inspect and test, except for joints filled with insulating paste or encapsulated. 543.3.3 Switching electrical appliances should not be connected to the protective conductors, but joints that can only be disconnected by tools for testing may be provided. 543.3.4 When electrical monitoring is used for grounding continuity, the operating coil should not be connected to the protective conductor. 543.3.5 The exposed conductive parts of electrical appliances should not be used as part of the protective conductor of other equipment, except as permitted in Article 543.2.2. 544 Grounding arrangements for protective purposes
Note: For protective measures for TN, TT and IT grounding systems, see GB14821.1. 544.1 Protective conductors used with overcurrent protective devices Note: When overcurrent protective devices are used for electric shock protection, it is strongly recommended to incorporate the protective conductor in the same wiring system as the live conductors, or to place it in close proximity to the protective conductor.
544.2 Grounding conductors and protective conductors of fault voltage operated protectors 544.2.1 There should be an auxiliary grounding electrode that is electrically unconnected to all other grounded metal bodies, such as metal components, pipelines or metal sheathed cables. This requirement is considered to have been met if the installed auxiliary grounding electrode is located at a specified distance (this value is under consideration) from all other grounded metal bodies.
544.2.2 The grounding conductor leading to the auxiliary grounding electrode should be insulated to prevent it from touching the protective conductor or any part connected to the protective conductor, or conductive parts outside the device that may be touched. Note: This requirement is necessary to prevent voltage-sensitive components from being accidentally bridged. 544.2.3 The protective conductor shall be connected only to the exposed conductive parts of such electrical equipment: when a ground fault occurs, the power supply to these equipment is cut off by the action of the protective device.
544.3 Excessive leakage current to earth
The requirements are under consideration.
545 Grounding configuration for functional purposes
545.1
—General requirements
The grounding configuration for functional purposes shall ensure the normal operation of the equipment, or enable the equipment to reliably and correctly perform its functions (more requirements 42
under consideration).
545.2 Low noise
Under consideration
546 Grounding configuration with both protection and functional purposes 546.1 General requirements
GB 16895.3—1997
The grounding configuration with both protection and functional purposes shall first meet the requirements of the protection measures. 546.2 PEN conductor
546.2.1 In TN systems, for cables with a copper core cross-section of not less than 10 mm2 or an aluminum core cross-section of not less than 16 mm2 in fixed installations, a single conductor may serve as both a protective conductor and a neutral conductor, provided that that part of the installation is not protected by a residual current operated protector. However, if the cable is a concentric cable that complies with IEC standards and all joints and terminals along the entire length of the concentric core are double-conductingly connected, the minimum cross-section of the PEN conductor may be 4 mm2. 546.2.2 The PEN conductor shall be insulated at the highest voltage to which it may be subjected to avoid the generation of stray currents. Note: PEN conductors inside complete switchgear and control equipment do not need to be insulated. 546.2.3 If the functions of the neutral conductor and the protective conductor are provided by their own conductors from any point in the installation, it is not allowed to connect these conductors to each other from that point. At the separation point, terminals or busbars for connecting the protective conductor and the neutral conductor shall be provided respectively. The PEN conductor shall be connected to the terminal or busbar for the protective conductor. 547 Equipotential bonding conductors
547.1 Minimum cross-section
547.1.1 Total equipotential bonding conductor
The cross-section of the total equipotential bonding conductor shall not be less than half the cross-section of the largest protective conductor of the installation, but shall not be less than 6 mm2. If the bonding conductor is copper wire, its cross-section need not be greater than 25 mm2. If it is other metal, its cross-section need not be greater than the cross-section that can carry the same current-carrying capacity as 25 mm2 of copper wire.
547.1.2 Auxiliary equipotential bonding conductors
The cross-section of an auxiliary equipotential bonding conductor connecting two exposed conductive parts may not be less than the cross-section of the smaller protective conductor connected to the two exposed conductive parts.
The cross-section of an auxiliary equipotential bonding conductor connecting an exposed conductive part to a conductive part outside the installation may not be less than half the cross-section of the corresponding protective conductor.
The provisions of 543.1.3 shall be complied with.
Auxiliary equipotential bonding can use the conductive part outside the permanent device such as metal components, or use auxiliary conductors, or both.
547.1.3 Connection of water meter
When the water pipe of the building is used as the grounding or protective conductor, the water meter should be connected across the connection. The cross-section of the bonding conductor should be selected according to the requirements of its use as a protective conductor, equipotential bonding conductor or functional grounding conductor. 547.2 Ungrounded equipotential bonding
Under consideration.
43
The coefficient is determined by the following formula:
GB16895.3-1997
Appendix A
The calculation method for the coefficient in Article 543.1.1
k
Q.(B + 20),
Inl1+
P20
Where: Q. —Volume heat capacity of a conductor material, J/℃·mm\); R + 0
BThe reciprocal of the temperature coefficient of resistivity of the conductor material at 0℃, ℃; P20
8
8
Material
Steel
Aluminum
Lead
Steel
The resistivity of a conductor material at 20℃, Q·mm; Initial temperature of the conductor, ℃;
Final temperature of the conductor, ℃.
B·
℃
234.5
228
230
202
Q
J/(C ·mm3)
3.45×10-3
2.5×10-3
1.45×10-3
3.8×10-3
*The values ??are taken from GB3953, GB3955 and IEC287 (Table). **The values ??are taken from ELECTRA, October 24, 1972, page 63. Appendix B
Earthing and protective conductor
B
pao
n.mm
17. 241 ×10-6
28.264 ×10-c
214×10-6
138×10-6
Q (B+20)
Pzo
226|| tt||148
41
78
1—Protective conductor: 2—Total equipotential bonding conductor: 3—Grounding conductor, 4—Auxiliary equipotential bonding conductor: B-- General grounding terminal; M - exposed conductive part; C - conductive part outside the device: P - metal water main pipe, T - grounding electrode 44
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