Connections and connections of grounding, protective conductors and conductors of the equalization and potential equalization system must be reliable and ensure continuity of the electrical circuit. It is recommended to make connections of steel conductors by welding. It is allowed to connect grounding and neutral protective conductors in indoor and outdoor installations without aggressive environments in other ways that meet the requirements of GOST 10434 "Contact electrical connections. General technical requirements" for the 2nd class of connections.
Connections must be protected from corrosion and mechanical damage.
For bolted connections, provisions must be made to prevent contact loosening.
1.7.140
Connections must be accessible for inspection and testing, with the exception of connections filled with compound or sealed, as well as welded, soldered and pressed connections to heating elements in heating systems and their connections located in floors, walls, ceilings and in the ground.
1.7.141
When using devices for monitoring the continuity of the grounding circuit, it is not allowed to connect their coils in series (in a cut) with the protective conductors.
1.7.142
Connections of grounding and neutral protective conductors and potential equalization conductors to open conductive parts must be made using bolted connections or welding.
Connections to equipment that is subject to frequent disassembly or installed on moving parts or parts subject to shock and vibration must be made using flexible conductors.
Connections of protective conductors of electrical wiring and overhead lines should be made using the same methods as connections of phase conductors.
When using natural grounding conductors for grounding electrical installations and third-party conductive parts as protective conductors and potential equalization conductors, contact connections should be made using the methods provided for by GOST 12.1.030 "SSBT. Electrical safety. Protective grounding, grounding"
1.7.143
Places and methods of connecting grounding conductors to extended natural grounding conductors (for example, pipelines) must be selected such that when disconnecting the grounding conductors for repair work, the expected touch voltages and the calculated resistance values of the grounding device do not exceed safe values.
Shunting of water meters, valves, etc. should be carried out using a conductor of the appropriate cross-section, depending on whether it is used as a protective conductor of the potential equalization system, a neutral protective conductor or a protective grounding conductor.
1.7.144
The connection of each open conductive part of the electrical installation to the neutral protective or protective grounding conductor must be made using a separate branch. The series connection of exposed conductive parts into the protective conductor is not permitted.
The connection of conductive parts to the main potential equalization system must also be made using separate branches.
The connection of conductive parts to an additional potential equalization system can be done using either separate branches or connection to one common permanent conductor.
1.7.145
It is not allowed to include switching devices in circuits P.E.- And PEN- conductors, with the exception of cases of power supply to electrical receivers using plug connectors.
It is also allowed to simultaneously disconnect all conductors at the input to electrical installations of individual residential, country and garden houses and similar objects fed by single-phase branches from overhead lines. At the same time, the division PEN- conductor on P.E.- and - conductors must be installed before the input protective switching device.
1.7.146
If the protective conductors and/or potential equalization conductors can be disconnected using the same plug connector as the corresponding phase conductors, the socket and plug of the plug connector must have special protective contacts for connecting the protective conductors or potential equalization conductors to them.
If the body of the socket outlet is made of metal, it must be connected to the protective contact of that socket.
By the way, Dear experts, here is another comment on my original question, only from the ElectroAS website:
my question was this -
“How many conductors can be connected to one bolt?
Can you enlighten me on a question that is very difficult in my opinion: when, during the construction of industrial enterprises and in residential construction, electricians connect 2 wires under one grounding bolt, coming, for example, from two adjacent switchboards, are they right? I think they are wrong, because... in the PUE there is a requirement (1.7.119 - PUE 7th) for the main grounding bus - “The design of the bus must provide for the possibility of individual disconnection of the conductors connected to it. Disconnection must only be possible using a tool." Does this mean that in general, absolutely everywhere and not only on the GZSH, ONLY one grounding wire should be clamped under one bolt? This opinion or understanding is broken by the work of one scientist - R.N. KARYAKIN, Doctor of Engineering. Sciences, Professor STANDARDS FOR CONSTRUCTION OF GROUNDING NETWORKS, MOSCOW, Energoservice, 2002. There he writes like this (by the way, he interprets GOST R 50571 (IEC364) as well): “10.5.4. It is prohibited to connect more than two cables to one grounding bolt (screw). tips. The grounding (zero) bus must be provided with bolted connections of the required number of grounding, neutral protective and neutral working conductors.
10.5.5. It is not required to deliberately ground the housings of electrical equipment and devices installed on grounded metal structures, switchgears, switchboards, cabinets, shields, frames of machines, machines and mechanisms, provided that reliable electrical contact with grounded bases is ensured.” That is, the author states that no more than two tips can be placed under the bolt. But he described this about shields, obviously for a bolt inside the shields, and not for wires with lugs that fit on the bolts of the grounding loop, which usually runs nearby. GOST 10434-82 also states that it is allowed to install 2 grounding wires under one bolt (Excerpt from GOST: (Changed edition, Amendment No. 1, 2).
2.1.12. It is recommended to connect no more than two conductors to each bolt (screw) of a flat terminal or to a pin terminal, unless otherwise specified in the standards or technical specifications for specific types of electrical devices.), but this GOST seems to be general technical and at the beginning of its text the following is written: “The requirements of the standard regarding the permissible value of electrical resistance and durability of contact connections during through currents also apply to contact connections in circuits of grounding and protective conductors made of steel.
The standard does not apply to electrical contact connections of special-purpose electrical devices.” There is a confusion of opinions here and all the documents bypass the exact instructions - after all, one or two wires (tip) need to be placed under one bolt. Why is it that in PUE 7 it is precisely about the GZSh, but nothing precise is written about the rest of the grounding and, in particular, about my question voiced? Please help me figure out how to understand all this and come to one correct understanding."
answer:
Message from FAQ
When, during the construction of industrial enterprises and in residential construction, electricians connect 2 wires under one grounding bolt, coming, for example, from two adjacent switchboards, are they right?
The ban applies to connecting more than two conductors, but up to two are always welcome. Although I personally think that it is necessary to tighten it and register - no more than one conductor.
Message from FAQ
I think they are wrong, because... in the PUE there is a requirement (1.7.119 - PUE 7th) for the main grounding bus - “The design of the bus must provide for the possibility of individual disconnection of the conductors connected to it.
And where did you find in paragraph 1.7.119 the prohibition on connecting 2 conductors? Connecting two lugs in a bolt does not make it impossible to individually disconnect the connected conductors. He unscrewed the nut, removed the corresponding tip and screwed the nut back on. What is the problem?
Message from FAQ
Does this mean that in general, absolutely everywhere and not only on the GZSH, ONLY one grounding wire should be clamped under one bolt?
Where did you find the prohibitions?
Message from FAQ
The standard does not apply to electrical contact connections of special-purpose electrical devices.”
For a complete understanding, you need to familiarize yourself with the terms and definitions of basic concepts.
GOST 18311-80
This standard establishes terms and definitions in the field of electrical products
Types of electrical products, electrical devices, electrical equipment
15. Electrical product (electrical device, electrical equipment) of general purpose - an electrical product (electrical device, electrical equipment) that satisfies a set of technical requirements common to most applications.
16. Electrical product (electrical device, electrical equipment) for special purposes - an electrical product (electrical device, electrical equipment) made taking into account requirements specific to a specific purpose or for certain operating conditions and (or) having special performance characteristics and (or) a special design .
17. Electrical product (electrical device, electrical equipment) for a specialized purpose - an electrical product (electrical device, electrical equipment) for a special purpose, adapted for use with only one specific object.
Message from FAQ
There is a confusion of opinions here and all the documents bypass the exact instructions - after all, one or two wires (tip) need to be placed under one bolt.
No more than 2 conductors (tips) per bolt.
Message from FAQ
Why is it that in PUE 7 it is precisely about the GZSh, but nothing precise is written about the rest of the grounding and, in particular, about my question voiced?
You have confused the number of conductors with individual disconnection.
In general, comrade FAQ points out that 2 conductors under a bolt are NOT PROHIBITED!!! Well, about one conductor for one bolt on the GZSh - this only concerns the GZSh! Well, yes, most likely he is right... and Volk is right!!! I hope our dialogue has now fully revealed the understanding of the topic I raised! Let it become useful for all doubters))) I am also for tightening the requirements - one wire for one bolt! This is both correct and easy to remember)))
3.3. Requirements for protective grounding
3.3.1. Products whose purpose does not require a method of protecting people from electric shock corresponding to classes II and III must be equipped with a grounding element.
It is allowed to carry out the following products without a grounding element and not to ground them:
intended for installation in places that are inaccessible without the use of special means (including inside other products);
intended for installation only on grounded metal structures, if this ensures stable electrical contact of the contacting surfaces and fulfills the requirement of clause 3.3.7;
parts of which cannot be under alternating voltage higher than 42 V and under direct voltage higher than 110 V;
grounding of which is not permitted by the principle of operation or purpose of the product.
(Changed edition, Amendment No. 1, 3).
3.3.2. To connect the grounding conductor, welded or threaded connections must be used.
By agreement with the consumer, the grounding conductor can be connected to the product by soldering or crimping performed by a special tool, fixture or machine.
3.3.3. Grounding clamps must comply with the requirements of GOST 21130-75.
It is not allowed to use bolts, screws, or studs that act as fasteners for grounding.
3.2.2-3.3.3. (Changed edition, Amendment No. 1).
3.3.4. The bolt (screw, stud) for connecting the grounding conductor must be made of metal that is resistant to corrosion, or coated with metal that protects it from corrosion, and the contact part must not have surface coloring.
(Changed edition, Amendment No. 4).
3.3.5. The grounding bolt (screw, stud) must be placed on the product in a place that is safe and convenient for connecting the grounding conductor. Near the place where the grounding conductor, provided for in clause 3.3.2, is to be connected, a grounding sign, applied in any way and indelible during operation, must be placed. The dimensions of the sign and the method of its implementation are in accordance with GOST 21130-75, and for lamps - in accordance with GOST 17677-82.
There must be a contact pad around the bolt (screw, stud) for connecting the grounding conductor. The platform must be protected from corrosion or made of anti-corrosion metal, and not have surface painting.
Measures must be taken against possible loosening of the contacts between the grounding conductor and the grounding bolt (screw, stud) (lock nuts, spring washers).
The diameters of the bolt (screw, stud) and contact pad must be selected according to the current (see Table 1).
Table 1
Rated current of electrical equipment Nominal diameter of the thread for the place Diameter of the contact pad of the connection point, mm
products, And connections, not less on the surface plane, elevated relative to the surface
St. 4 to 6 M 3 10 7
"6" 16 M 3.5 11 8
"16" 40 M 4 12 9
" 40 " 63 M 5 14 11
" 63 " 100 M 6 16 12
" 100 " 250 M 8 20 17
" 250 " 630 M 10 25 21
" 630 M 12 28 24
Notes:
1. For currents above 250 A, it is allowed to install two bolts instead of one, but with a total cross-section not less than the required one.
When choosing the smallest bolt diameter for consumers and converters of electromagnetic energy, the current value should be taken as the current. consumed by the product from the source (network), for sources of electromagnetic energy - the value of the rated load current.
2. For electromagnetic energy sources having several rated currents, the bolt diameter should be selected based on the largest of these currents.
(Changed edition, Amendment No. 1, 3, 4).
3.3.6. If the dimensions of the product are small, and also if the grounding bolt (screw) is installed by welding its head, it is allowed to provide the necessary contact surface in connection with the grounding conductor using washers. The material of the washers must meet the same requirements as the material of the grounding bolt (screw, stud).
3.3.7. The product must have an electrical connection between all touchable metal non-current-carrying parts of the product that may be energized with grounding elements.
The resistance value between the grounding bolt (screw, pin) and each accessible metal non-current-carrying part of the product, which may be energized, should not exceed 0.1 Ohm.
3.3.8. The following metal non-current-carrying parts of products to be grounded must be equipped with grounding elements:
shells, cases, cabinets;
frames, frames, cages, racks, chassis, bases, panels, slabs and other parts of products that may become live if the insulation is damaged.
It is allowed not to provide grounding elements for the following parts of the product (from those listed above):
housings of products intended for installation on grounded switchboards, metal walls of switchgear chambers, in cabinets;
non-current-carrying metal parts of the product that have electrical contact with grounded parts, subject to the requirements of clause 3.3.7;
parts fixed in or passing through insulating material and isolated from both grounded and live parts (provided that during operation of the product they cannot become live or come into contact with grounded parts).
3.3.9. Each part of the product equipped with a grounding element must be designed so that:
there was the possibility of its independent connection to the ground electrode or grounding line through a separate branch, so that when any grounded part of the product is removed (for example, for routine repairs), the grounding circuits of other parts are not interrupted;
there was no need to connect several grounded parts of the product in series.
3.3.10. Grounding of parts of products installed on moving parts must be done with flexible conductors or sliding contacts.
3.3.11. If there is a metal shell, the element for grounding it must be located inside the shell.
It is possible to perform it outside the shell or to perform several elements both inside and outside the shell.
(Changed edition, Amendment No. 1).
3.3.12. Electrical contact between the removable and grounded (non-removable) parts of the shell must be achieved by directly pressing the removable part against the non-removable part; at the same time, in places of contact, the surfaces of the removable and non-removable parts of the shell must be protected from corrosion and not covered with electrically insulating layers of varnish, paint or enamel.
It is allowed to electrically connect the removable part of the shell with the non-removable grounded part through the screws or bolts securing it, provided that 1-2 screws or bolts have an anti-corrosion metal coating, and between the heads of these screws or bolts and the removable metal part of the shell there is no electrically insulating layer of varnish, paint, enamels or between them, serrated washers are installed that destroy the electrical insulating layer to make an electrical connection or without serrated washers, provided that the removable part is attached to a non-removable grounded one with six or more bolts (or screws) and there is no electrical connection on the removable parts of electrical devices.
It is also permissible to use toothed washers for the electrical connection of the grounded shell and equipment mounted in the product, and to install them for grounding the elements of the product through bolted connections.
(Changed edition, Amendment No. 3).
3.3.13. The requirements listed in clause 3.3 do not apply to products intended for use only in areas with a tropical climate and made in accordance with GOST 15151-69, GOST 9.048-89.
CONTACT ELECTRICAL CONNECTIONS CLASSIFICATION. GENERAL TECHNICAL REQUIREMENTS GOST 10434-82
STATE STANDARD OF THE USSR UNION
CONTACT ELECTRICAL CONNECTIONS
Classification. General technical requirements
Electric contact connections. Classification.
General technical requirements
GOST 10434-82
Recording date 01/01/83
This standard applies to dismountable and non-separable electrical contact connections of busbars, wires or cables (hereinafter referred to as conductors) made of copper, aluminum and its alloys, steel, aluminum-copper wires with terminals of electrical devices, as well as contact connections of conductors with each other for currents from 2. 5 A. For contact connections of electrical devices for currents less than 2.5 A, the standard requirements are recommended. The requirements of the standard regarding the permissible value of electrical resistance and durability of contact connections during through currents also apply to contact connections in circuits of grounding and protective conductors made of steel.
The standard does not apply to electrical contact connections of special-purpose electrical devices.
The terms used in the standard correspond to GOST 14312-79, GOST 18311-80.
1. CLASSIFICATION
1.1. Depending on the area of application, electrical contact connections (hereinafter referred to as contact connections) are divided into classes in accordance with table. 1.
Table 1
| Scope of contact connection | Contact class |
|---|---|
| 1. Contact connections of circuits whose conductor cross-sections are selected according to permissible long-term current loads (power electrical circuits, power lines, etc.) | 1 |
| 2. Contact connections of circuits, the conductor cross-sections of which are selected for resistance to through currents, voltage loss and deviation, mechanical strength, and overload protection. Contact connections in circuits of grounding and protective conductors made of steel | 2 |
| 3. Contact connections of circuits with electrical devices, the operation of which is associated with the release of a large amount of heat (heating elements, resistors, etc.) | 3 |
Note. Standards and technical specifications for specific types of electrical devices must indicate classes 2 and 3; class 1 is not indicated.
1.2. Depending on the climatic version and the category of placement of electrical devices according to GOST 15150-69, contact connections are divided into groups in accordance with table. 2.
1.3. According to their design, contact connections are divided into non-separable and collapsible.
1.4. Depending on the material of the connected conductors and the group of contact connections according to clause 1.2, dismountable contact connections are divided into:
- - not requiring the use of means for stabilizing electrical resistance - see paragraphs. 2.1.6 and 2.1.8;
- requiring the use of means of stabilizing electrical resistance - see paragraphs. 2.1.7 and 2.1.8.
table 2
| Climatic modification and category of electrical device placement | |
|---|---|
| 1. All climatic versions for location category 4.1 with atmosphere types II and I. Climatic modifications U, UHL, TS for placement category 3 and climatic modifications UHL, TS for placement category 4 in an atmosphere of types II and I |
A |
| 2. Any combination of climatic design and placement category, except those indicated above, with an atmosphere of types II and I. Any combination of climatic design and location category with atmosphere types III and IV |
B |
2. TECHNICAL REQUIREMENTS
2.1. Design requirements
2.1.1. Contact connections must be made in accordance with the requirements of this standard, standards and technical specifications for specific types of electrical devices according to working drawings approved in the prescribed manner.
2.1.2. The terminals of electrical devices must comply with the requirements of GOST 24753-81.
2.1.3. Contact screw terminals must comply with the requirements of GOST 25034-85, type-set terminals must comply with the requirements of GOST 19132-86.
2.1.4. Linear fittings must comply with the requirements of GOST 13276-79.
2.1.5. Permanent contact connections must be made by welding, soldering or crimping. It is permissible to use other methods specified in the standards or technical specifications for specific types of electrical devices.
Examples of making permanent contact connections are given in Appendix 1.
2.1.6. Demountable contact connections that do not require the use of means for stabilizing electrical resistance must be made using steel fasteners protected from corrosion in accordance with the requirements of GOST 9.303-84, GOST 9.005-72.
2.1.7. Demountable contact connections requiring the use of means for stabilizing electrical resistance must be made using both individually and in combination the following means:
- 1) fasteners made of non-ferrous metals with a linear expansion coefficient from 18·10 -6 to 21·10 -6 1/°С;
2) disc springs in accordance with GOST 3057-90 or technical specifications for specific types of springs;
3) protective metal coatings of working surfaces, selected according to GOST 9.303-84, taking into account the requirements of GOST 9.005-72.
It is allowed to use other types of protective coatings specified in the standards or technical specifications for specific types of electrical devices;
4) transition parts in the form of copper-aluminum plates in accordance with GOST 19357-81, copper-aluminum tips in accordance with GOST 9581-80 and hardware clamps made of clad aluminum in accordance with TU 34-13-11438-89;
5) transition parts in the form of plates and tips made of aluminum alloy with a tensile strength of at least 130 MPa (hereinafter referred to as hard aluminum alloy);
6) pin tips according to GOST 23598-79 made of hard aluminum alloy;
7) pin tips according to GOST 23598-79, copper-aluminum;
8) electrically conductive lubricants or other electrically conductive materials, if the possibility of their use is confirmed by test results in accordance with GOST 17441-84 and is specified in the standards or technical specifications for specific types of electrical devices.
When using means 2)-8), contact connections, as a rule, must be made using steel fasteners protected from corrosion in accordance with the requirements of GOST 9.303-84, GOST 9.005-72.
Note. The need to apply a protective metal coating to the working surfaces of copper conductors must be specified in the standards or technical specifications for specific types of electrical devices.
(Changed edition, Amendment No. 1, 2, 3).
2.1.8. Demountable contact connections, depending on the group according to clause 1.2 and the material of the connected conductors and terminals of electrical devices, must be made in accordance with the requirements of the standard specified:
- - for contact connections of conductors with flat leads, as well as contact connections of conductors among themselves - in table. 3;
- for contact connections of conductors with pin terminals - in table. 4;
- for contact connections of conductors with socket terminals - in table. 5.
Table 3
| Contact group | Conductor material | Standard clause number depending on the terminal material or second conductor | |||
|---|---|---|---|---|---|
| copper and its alloys | hard aluminum alloy | aluminum | steel | ||
| A | Copper, aluminum copper | 2.1.6 | 2.1.6 | ||
| Solid aluminum alloy | |||||
| Aluminum | 2.1.7 1) or 2), or 3), or 4), or 5), or 8) | ||||
| B | Copper, aluminum copper | 2.1.6 | 2.1.6 | ||
| Solid aluminum alloy | 2.1.7* 3) or 4), or 5) and 3) | 2.1.6 | 2.1.7 4) or 5) and 3) | ||
| Aluminum | 2.1.7 4) or 5) and 3), or 1) and 3), or 2) and 3) | 2.1.7 1) or 2), or 3), or 4), or 5) | |||
Contact connections in accordance with the climatic design and the category of placement of electrical devices, determined according to GOST 15150-69 and GOST 15543-70, must withstand the influence of environmental climatic factors specified in GOST 15150-69, GOST 15543-70, GOST 15963-79, GOST 16350-80, GOST 17412-72 or in standards and technical specifications for specific types of electrical devices.
Table 4
| Contact group | Conductor material | Standard clause number depending on pin material | ||
|---|---|---|---|---|
| copper or brass for rated current | steel for rated current up to 40 A | |||
| up to 630 A | above 630 A | |||
| A | Copper, aluminum copper | 2.1.6 | ||
| Solid aluminum alloy | ||||
| Aluminum | 2.1.7 1) | 2.1.7 3) or 4), or 5) | 2.1.7 2) or 3), or 4), or 5) | |
| B | Copper, aluminum copper | 2.1.6 | ||
| Solid aluminum alloy | 2.1.7 4) or 5) and 3) | 2.1.7* 4) or 5) and 3) | 2.1.7 4) or 5) and 3) | |
| Aluminum | 2.1.7 4) or 5) and 3) | |||
* Contact connections of electrical devices of climatic versions U, UHL of placement categories 1 and 2 may be manufactured according to clause 2.1.6.
Note. In all cases, copper or brass thrust nuts must be used for pin terminals rated above 40 A.
Table 5
| Contact group | Conductor material | Standard clause number depending on the type of core | |
|---|---|---|---|
| single-wire | stranded | ||
| A | Copper | Direct connection | |
| Aluminum copper | - | ||
| Aluminum | Direct connection* or 2.1.7 6) or 7)** | ||
| B | Copper | Direct connection* or 2.1.6*** | 2.1.6*** |
| Aluminum copper | - | ||
| Aluminum | 2.1.7 7) or 6) and 3) | ||
* The possibility of direct connection must be specified in the standards or technical specifications for a specific type of electrical device.
** It is allowed to connect aluminum cores fused into a monolith with the addition of alloying additives from a hard aluminum alloy.
*** The contact connection is made by terminating with copper pin tips in accordance with GOST 22002.5-76, GOST 22002.12-76, GOST 22002.13-76, GOST 23598-79 or by tinning the cores with tin-lead solders in accordance with GOST 21931-76.
It is allowed, by agreement with the consumer, to use contact connections that differ from those indicated in the table. 3-5.
Examples of making collapsible contact connections are given in Appendix 2.
(Changed edition, Amendment No. 1, 3).
2.1.9. Contact connections of plates made of hard aluminum alloy and the aluminum part of copper-aluminum plates with aluminum conductors (leads) must be made by welding or soldering, and connections of lugs made of hard aluminum alloy and the aluminum part of copper-aluminum lugs with aluminum conductors of wires and cables must be made by welding or crimping.
2.1.10. Dismountable contact connections of single-wire conductors of wires and cables with flat or pin terminals must be carried out:
- - cores with a cross-section of up to 16 mm 2 - after termination with lugs in accordance with GOST 7386-80 or directly: by forming into a ring or without it, with protection in both cases from extrusion with shaped washers or other methods;
- cores with a cross-section of 25 mm 2 or more - after termination with lugs in accordance with GOST 7386-80, GOST 7387-82, GOST 9581-80 or by forming the end of the core into a flat clamping part with a hole for a bolt.
2.1.11. Demountable contact connections of stranded wires and cables with flat or pin terminals must be carried out:
- - cores with a cross section of up to 10 mm 2 - after termination with lugs in accordance with GOST 7386-80, GOST 9688-82, GOST 22002.1-82, GOST 22002.2-76 - GOST 22002.4-76, GOST 22002.6-82, GOST 22002.7-76 - GOST 2200 2.11- 76, GOST 22002.14-76 or directly: by forming into a ring or without it, with protection in both cases from extrusion with shaped washers, or other methods;
- cores with a cross-section of 16 mm 2 or more - after termination with lugs in accordance with GOST 7386-80, GOST 7387-82, GOST 9581-80, GOST 22002.1-82, GOST 22002.2-76, GOST 22002.6-82, GOST 22002.7-76.
(Changed edition, Amendment No. 1, 2).
2.1.12. It is recommended to connect no more than two conductors to each flat terminal bolt (screw) or pin terminal, unless otherwise specified in the standards or technical specifications for specific types of electrical devices.
2.1.13. In collapsible contact connections, fasteners of strength classes in accordance with GOST 1759.4-87 and GOST 1759.5-87 specified in table should be used. 6. It is recommended to use screws in contact connections with a cylindrical or hexagonal head.
Table 6
2.1.14. Requirements for the preparation of working surfaces of contact parts are given in Appendix 3.
2.2. Electrical Requirements
2.2.1. The ratio of the initial electrical resistance of contact connections (except for contact connections with pin terminals) to the electrical resistance of the section of connected conductors, the length of which is equal to the length of the contact connection, should not exceed:
- - for class 1 - 1, unless otherwise specified in the standards or technical specifications for specific types of electrical devices;
- for class 2 - 2;
- for grades 3 - 6.
In contact connections of conductors with different electrical resistance, a comparison is made with a contact part with greater electrical resistance.
2.2.2. The initial electrical resistance of contact connections of class 1 conductors with pin terminals should not exceed the values specified in table. 7.
Table 7
Requirements for contact connections of classes 2 and 3, if necessary, are specified in standards or technical specifications for specific types of electrical devices.
2.2.3. The electrical resistance of contact connections (except welded and soldered), tested for compliance with the requirements of standards and other technical documentation according to the method specified in GOST 17441-84, should not exceed the initial value by more than 1.5 times. The electrical resistance of welded and soldered contact connections must remain unchanged. The need for mandatory use of torque indicator keys must be indicated in the standards or technical specifications for specific types of electrical devices.
2.2.4. When the rated (long-term permissible) current flows, the maximum permissible temperature of contact connections of classes 1 and 2 should not exceed the values indicated in table. 8. In this case, the current loads of conductors are taken according to the “Rules for the Construction of Electrical Installations”, approved by Gosenergonadzor on April 12, 1969, according to standards or technical specifications for specific types of electrical devices.
Table 8
| Characteristics of connected conductors | Highest permissible heating temperature, °C in installations | |
|---|---|---|
| up to 1000 V | St. 1000 V | |
| 1. Conductors made of copper, aluminum-copper, aluminum and its alloys without protective coatings of working surfaces | 95 | According to GOST 8024-90 |
| 2. Conductors made of copper, aluminum-copper, aluminum and its alloys with protective coatings of working surfaces with base metals | 110* | |
| 3. Conductors made of copper and its alloys without insulation or with insulation of classes B, F and H according to GOST 8865-87 with a protective coating of working surfaces with silver | 135 | |
* It is allowed for conductors made of copper without insulation or with insulation of classes B, F and H according to GOST 8865-87 to increase the temperature to 135 ° C, if the possibility of this is confirmed by test results according to GOST 17441-84 and is indicated in the standards or technical specifications for specific types electrical devices.
The temperature of class 3 contact connections is established in standards or technical specifications for specific types of electrical devices, depending on the materials used, coatings, insulation class of connected conductors and operating conditions.
(Changed edition, Amendment No. 1, 2, 3).
2.2.5. (Deleted, Amendment No. 1).
2.2.6. After the through current mode, the contact connections should not have mechanical damage that would prevent their further operation. The temperature of contact connections in through current mode should not be more than 200 °C for connections of conductors made of aluminum copper, aluminum and its alloys, as well as for connections of these conductors with copper, 300 °C for connections of copper conductors and 400 °C for connections of steel conductors.
2.2.7. The value of the permissible through current of contact connections must be no less than the permissible through currents of specific types of electrical devices specified in the standards or technical specifications for these devices.
In the absence of these data, the value of the one-second current density should correspond to 165 A/mm 2 - for copper conductors, 105 A/mm 2 - for aluminum and aluminum-copper conductors, 90 A/mm 2 - for conductors made of aluminum alloy and 20 A/mm 2 - for steel conductors.
(Changed edition, Amendment No. 1).
2.3. Requirements for resistance to mechanical factors
2.3.1. Contact connections must withstand the effects of mechanical environmental factors according to the group of operating conditions in accordance with GOST 17516-72, which must be specified in the standards or technical specifications for specific types of electrical devices.
In the absence of such instructions, contact connections subject to vibration must withstand vibration for 1 hour at a constant frequency of 40 to 50 Hz and an amplitude of 1 mm.
2.3.2. Contact connections must withstand the effects of static axial tensile loads causing stresses of at least:
- - 90% of the tensile strength of the entire conductor - for contact connections of power line wires operating in tension;
- 30% tensile strength of an entire conductor - for permanent contact connections that do not work in tension, as well as for connections of conductors with socket terminals, connections of unterminated wires and cables with flat terminals equipped with shaped washers.
For conductors with a cross section of up to 1.5 mm2, it is not allowed to use a screw clamp, the end of the screw of which is rotated along the core.
2.3.1.-2.3.3. (Changed edition, Amendment No. 1).
2.3.4. Dismountable contact connections of conductors with leads, single-bolt contact connections that may be exposed to through short-circuit currents, as well as dismountable contact connections subject to vibration or located in explosive areas must be protected from self-unscrewing by locknuts, spring washers, disc springs or other means.
(Changed edition, Amendment No. 2).
2.4. Reliability requirements
2.4.1. To assess the reliability of contact connections, a gamma-percentage resource is established, unless otherwise established in the standards or technical specifications for specific types of electrical devices.
The lower value of the gamma percentage resource must ensure the operation of electrical devices in accordance with the reliability requirements established in the standards or technical specifications for these electrical devices.
(Changed edition, Amendment No. 1).
2.5. Safety requirements
2.5.1. Contact connections in terms of safety requirements must comply with GOST 12.2.007.0-75 and ensure the operating conditions established by the “Rules for the technical operation of consumer installations” and “Safety rules for the operation of consumer electrical installations”, approved by Gosenergonadzor on April 12, 1969.
2.5.2. Contact connections in terms of fire safety requirements must comply with GOST 12.1.004-91, which is ensured by meeting the requirements of GOST 10434-82.
(Introduced additionally, Amendment No. 3).
ANNEX 1
Information
PERMANENT CONTACT CONNECTIONS
a - welding or soldering; b - with pin terminal welding; c - welding through a transition copper-aluminum plate; d - connection of wire (cable) cores through a connecting sleeve by crimping; d - connection of a wire (cable) core with a cable lug by crimping (welding, soldering); e - connection of wire cores in oval connectors
1 - flat output (bus); 2 - tire; 3 - pin terminal; 4 - copper-aluminum plate; 5 - wire (cable); 6 - connecting sleeve; 7 - cable lug; 8 - oval connector
APPENDIX 2
Information
DISMOUNTABLE CONTACT CONNECTIONS
a - with a lock nut; b - with a spring washer; c - single-wire (multi-wire) core of wire (cable) cross-section. up to 10 mm 2 with bending into a ring; g - single-wire (multi-wire) wire (cable) core cross-section. up to 10 mm 2 without bending into a ring.
1 - flat output (bus); 2 - bus (cable lug); 3, 4, 5 - steel washer, bolt and nut; 6 - spring washer; 7 - screw; 8 - shaped washer (star washer); 9 - wire (cable); 10 - shaped washer (arched washer)
a - fasteners made of non-ferrous metal with a lock nut; b - fasteners made of non-ferrous metal with a spring washer; c - steel fasteners with a disc spring; d - steel fasteners with protective metal coatings on working surfaces with a lock nut (spring washer); d - steel fasteners through a transition copper-aluminum plate with a lock nut (spring washer); e - steel fasteners through an adapter plate made of hard aluminum alloy with a lock nut (spring washer).
1 - flat output (bus); 2 - bus (cable lug); 3 - 5 - washer, bolt, nut made of non-ferrous metal; 6 - spring washer; 7 - steel nut; 8 - steel bolt; 9 - disc spring; 10 - steel washer (enlarged washer); 11 - steel washer; 12 - flat terminal (bus) with a protective metal coating of the working surface; 13 - busbar (cable lug) with a protective metal coating of the working surface; 14 - copper-aluminum plate; 15 - hard aluminum alloy plate
a - conductor made of copper, hard aluminum alloy or aluminum with a protective metal coating of the working surface; b, c, d - aluminum conductor; d - aluminum conductor through a copper-aluminum transition plate; e - single-wire (multi-wire) core of the cable cross-section. 10 mm 2 with bending into a ring.
1-pin copper or brass terminal; 2 - nut made of copper or brass; 3 - busbar (cable lug) made of copper, hard aluminum alloy or aluminum with a protective metal coating of working surfaces; 4 - steel nut; 5 - pin copper terminal; 6 - steel washer; 7 - aluminum busbar (cable lug); 8 - pin brass terminal; 9 - pin steel terminal; 10 - disc spring; 11 - copper-aluminum plate; 12 - wire (cable); 13 - spring washer; 14 - shaped washer (star washer)
a, b - single-wire (multi-wire, fused into a monolith) core; c - stranded core terminated with a cable lug.
1 - dial clamp; 2 - wire (cable); 3 - socket output; 4 - pin cable lug
REQUIREMENTS FOR PREPARATION OF WORKING SURFACES OF CONTACT PARTS
1. Contact parts that have two or more holes for bolts in a transverse row are recommended to be made with longitudinal cuts, as shown in the drawing.
2. The working surfaces of contact parts of dismountable contact connections and non-separable contact connections with linear fittings must be prepared immediately before assembly:
- - copper without coating and aluminum-copper - stripped.
When stripping aluminum-copper wires, the copper sheath should not be damaged;
- aluminum and aluminum alloys - cleaned and lubricated with neutral lubricant (KVZ Vaseline in accordance with GOST 15975-70, CIATIM-221 in accordance with GOST 9433-80 or other lubricants with similar properties).
The recommended time between cleaning and lubrication is no more than 1 hour;
- working surfaces with protective metal coatings are washed with an organic solvent.
(Changed edition, Amendment No. 3).
3. The working surfaces of copper contact parts connected by crimping must be cleaned, unless otherwise specified in the standards or technical specifications for specific types of electrical devices.
The working surfaces of aluminum contact parts must be cleaned and lubricated with quartz-vaseline paste or other lubricants, pastes and compounds with similar properties.
4. The surfaces of contact parts connected by welding or soldering must first be cleaned, degreased or etched.
5. The location and size of holes for bolts in contact parts of dismountable contact connections is recommended to be taken in accordance with GOST 21242-75.
By agreement with the consumer, oval holes can be made.
(Introduced additionally, Amendment No. 2).
TORQUES
Table 9
| Thread diameter, mm | Torque, Nm, for bolted connection | |
|---|---|---|
| with slotted head (screws) | with hex head | |
| M3 | 0,5+0,1 | - |
| M3.5 | 0.8±0.2 | |
| M4 | 1.2±0.2 | |
| M5 | 2.0±0.4 | 7.5±1.0 |
| M6 | 2.5±0.5 | 10.5±1.0 |
| M8 | - | 22.0±1.5 |
| M10 | 30.0±1.5 | |
| M12 | 40.0±2.0 | |
| M16 | 60.0±3.0 | |
| M20 | 90.0±4.0 | |
| M24 | 130.0±5.0 | |
| M30 | 200.0±7.0 | |
| M36 | 240.0±10.0 | |
Note. For bolted connections of conductors made of copper and hard aluminum alloy, it is recommended to use torques whose values are 1.5 - 1.7 times higher than those specified in the table.
(Changed edition, Amendment No. 3).
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of Installation and Special Construction Works of the USSR
DEVELOPERS
N. N. Dzektser, Ph.D. tech. Sciences (topic leader); V. L. Fuks; O. V. Fesenko, Ph.D. tech. sciences
2. APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee for Product Quality Management and Standards dated 02/03/82 No. 450
3. INSTEAD GOST 10434-76
4. REFERENCED REGULATORY TECHNICAL DOCUMENTS
| Designation of the referenced technical document | Number of item, transfer, application |
|---|---|
| GOST 9.005-72 | |
| GOST 9.303-84 | 2.1.6; 2.1.7, items 3, 8 |
| GOST 12.1.004-91 | 2.5.2 |
| GOST 12.2.007.0-75 | 2.5.1 |
| GOST 1759.4-87 | 2.1.13 |
| GOST 1759.5-87 | 2.1.13. |
| GOST 3057-90 | 2.1.7, item 2 |
| GOST 7386-80 | 2.1.10; 2.l.11 |
| GOST 7387-82 | 2.1.10; 2.1.11 |
| GOST 8024-90 | 2.2.4 |
| GOST 8865-87 | 2.2.4 |
| GOST 9433-80 | Appendix 3 |
| GOST 9581-80 | 2.1.7, item 4; 2.1.10; 2.1.10; 2.1.11 |
| GOST 9688-82 | 2.1.11 |
| GOST 13276-79 | 2.1.4; 2.1.7 |
| GOST 14312-79 | Introductory part |
| GOST 15150-69 | 1.2; 2.1.8 |
| GOST 15543-70 | 2.1.8 |
| GOST 15963-79 | 2.1.8 |
| GOST 15975-70 | Appendix 3 |
| GOST 16350-80 | 2.1.8 |
| GOST 17412-72 | 2.1.8 |
| GOST 17441-84 | 2.1.7, item 8; 2.2.3; 2.2.4 |
| GOST 17516-72 | 2.3.1 |
| GOST 18311-80 | Introductory part |
| GOST 19132-86 | 2.1.3 |
| GOST 19357-81 | 2.1.7, item 4 |
| GOST 21242-75 | Appendix 3 |
| GOST 21931-76 | 2.1.8 |
| GOST 22002.1-82 | 2.1.11 |
| GOST 22002.2-76 - GOST 22002.4-76 | 2.1.11 |
| GOST 22002.5-76 | 2.1.8 |
| GOST 22002.6-82 | 2.1.11 |
| GOST 22002.7-76 - GOST 22002.11-76 | 2.1.11 |
| GOST 22002.12-76 | 2.1.8 |
| GOST 22002.13-76 | 2.1.8 |
| GOST 22002.14-76 | 2.1.11 |
| GOST 23598-79 | 2.1.7, listing 6, 7; 2.1.8 |
| GOST 24753-81 | 2.1.2 |
| GOST 25034-85 | 2.1.3 |
| GOST 34-13-11438-89 | 2.1.7, item 4 |
5. Validity period extended until 01/01/96 by Decree of the USSR State Committee for Product Quality Management and Standards dated 05/25/90 No. 1309
6. REISSUE (October 1993) with Amendments No. 1, 2, 3, approved in April 1985, June 1987, May 1990 (IUS 7-85, 10-87, 8-90)
