The functioning of any electrical appliance cannot be ensured without a good connection to the electrical cable. Copper cable lugs are used to create this contact. Their main properties are considered to be tightness and resistance to aggressive factors.
Content
- Varieties of tips
- Coated and uncoated products
- Special designation
- Installation methods
Varieties of tips
A simple connection to the mains is not enough for the efficient operation of the equipment. Another important condition is to ensure a reliable contract between the equipment and the wire. A bad connection can cause:
- overloads;
- power surges.
These situations in most cases lead to the fact that devices fail, require expensive repair or replacement. The use of special connectors will help to avoid such problems.
The material used for their production can be different. The most common are:
-
Aluminum. Suitable for wires with aluminum conductors with a cross section of 16-240 mm2. For their manufacture, a pipe made of aluminum of the AD1M brand is used. - Aluminum-copper. They are used to connect aluminum cables with copper leads of electrical devices. The cylindrical part of such products is made from an aluminum rod of the AD1M brand, the contact part on which the mounting hole is located is from a copper rod of the M1 brand. Both parts are connected by frictional diffusion.
- Copper. Used for wires with copper conductors with a diameter of 2.5-240 mm2. Solid-drawn copper pipes of the M2 brand and sheets of copper of the M1 and M2 brands are chosen as the starting material for them.
During the production of cable contacts, the standards prescribed by GOST are observed. To fix the terminals on the wires, the crimping method is most often used.
Coated and uncoated products
Copper is considered the most suitable material for cable lugs. This metal provides the fastener with sufficient strength and reliability. Copper parts have good air tightness, therefore, they can be successfully used on water equipment and devices operating in an aggressive environment.
The element made of copper is of two types: insulated or tin-plated. Each type has its own characteristics. Tinned tips are more practical to use. The coating perfectly protects parts from corrosion and significantly increases the period of their operation. They are not destroyed under the influence of nitric, hydrochloric, sulfuric acid and other aggressive factors (moisture, air of different temperatures). However, the presence of a protective coating reduces the electrical conductivity of the contacts.
Uncoated contacts are subject to rapid oxidation, resulting in a decrease in conductivity and an increase in resistance. Such a change in the current parameters leads to a rapid heating of the connection and subsequent breakdown of the device.
Special designation
Coated products have several varieties, differing in material and method of fastening. To designate products it is customary to use marking in the form of a combination of letters:
- TA. Aluminum tubular connector.
-
IEK. Copper plug. - NKB. Geophysical cable.
- RFI-M. Cable flag.
- TMD. Double blind tip.
- SIP. Self-supporting insulated contact, which has an annular mounting plate in its design.
- NShP. Straight, non-threaded copper pin tip.
- NSHVI. Bushing pin.
The abbreviation TML is usually used to designate a fixed electrolytic cell, which is a modified version of a threaded pin tip. A special type of crimper is required to install it.
Each marking symbol has a specific meaning:
- T. Pipe.
- W. Corner contact.
- L. Treated with tin.
The name of the material also appears on the tip label. The letter M marks copper, the letter A - aluminum, the letter L - brass products. The full designation of the cable lug consists of three letters and three numbers.
The first letter denotes the semi-finished product that was used to manufacture the connector, the second - the material of manufacture, the third - the coating (if any). Further there are numbers indicating the nominal contact cross-section, the diameter of the contact bar and the inner size of the shank. All numbers are indicated in millimeters.
Installation methods
The cable lugs are attached to the wires in different ways. Most often, their installation is carried out by welding, soldering or crimping. Also for this purpose, special installation bolts can be used.
The pressing method requires a special tool (press) that can be operated manually, mechanically or hydraulically, or by means of a pump. For the installation of a household contact, a manual mechanism - a stripper - or crimping pliers is suitable. It is not difficult to manually attach the lug to the copper or aluminum cable used to create grounding or wiring when connecting household electrical appliances.
Crimping a power cable requires a more powerful press and can be done in three ways. The metal core is inserted into the tubular tail of the tip and compressed in the die using a punch. In some places where the punch teeth are pressed the most, the best connection of the tip to the core is ensured.
With a solid crimp, equal pressure is guaranteed over the entire length of the ferrule. This achieves full electrical contact between the elements. For an improved connection of the tubular part with the cable, a combined crimp is used, which, under conditions of continuous crimping, provides additional compression at the point of entry of the teeth.
Equipment for crimping lugs can differ in the type of adjustable wrench or in the diameter of the hole. The standard hole is considered to be from 0.25 to 1 millimeter in size.
Creating a reliable contact with a soldering iron takes place in several stages. First, the cable, stripped to a shine and treated with neutral solder, is fully inserted into the connector, then solder is poured through a special hole.
During the installation of the cable lug using set screws, the size of their heads is automatically controlled inside the crimping machine. The bolts are screwed all the way into the connector hole, then their head breaks off. This ensures reliable and irreversible contact.
The advantage of bolted connections is that they can also be carried out without using a press using a wrench. In this case, the size of the connected cable can be several times less than the maximum diameter that is provided by the manufacturer for the tubular part of the lug.
