One of the most vital components for conduit installation with electrical steel pipes is the galvanized coupling. Couplings are metal ring-shaped parts that allow both ends of a pipe to be placed inside them via threading. Without electrical conduit couplings, it is not possible to create very long lengths for cable transmission. Therefore, this component can be recognized as one of the important fittings alongside pull elbows, electrical conduit clamps, and pull tees, whose quality plays a very important role in creating a safe connection in electrical conduit installations.
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A stainless steel coupling is one of the widely used fittings in electrical conduit systems and industrial facilities, used for connecting two pipes together and creating a continuous, safe, and corrosion-resistant path. Due to its stainless steel material, this type of coupling has higher strength and is considered a suitable choice for humid or industrial environments.
The outstanding feature of the stainless steel coupling is its high resistance to corrosion, heat, and pressure, especially in high-pressure models that are produced from seamless pipes. This plays an important role in increasing the safety of pipelines and preventing fluid leakage. Precise threading and the use of standard alloys in the production of this type of coupling guarantee long-term performance.
Using electrical conduit couplings is one of the mandatory standards in industrial and building electrical wiring and can prevent contaminants from entering the electrical conduit. Among the most important advantages of using couplings in electrical conduit installation are the following:
Creating electrical continuity: By creating a firm metal-to-metal connection, the coupling ensures that the entire conduit path acts as a protective conductor and maintains the safety of the earthing system against short-circuit faults.
Protecting cable insulation: The internal design of couplings is such that it covers the sharp and cutting edges of cut pipes. This prevents damage to the wire and cable sheathing during fishing and cable pulling.
Increasing mechanical strength: By evenly distributing stress at the connection point of two conduit branches, the coupling significantly increases the resistance of the entire line against physical impacts, industrial vibrations, and possible structural settlement.
Sealing and preventing contamination penetration: Using standard couplings (especially threaded or steel models) prevents dust, moisture, and suspended particles from entering the conduit, which directly increases the service life of the wiring.
Facilitating troubleshooting and expansion: Due to the detachable structure of couplings, in the event of a fault or the need to change the route, the desired section can be separated and new parts replaced without destroying the entire conduit installation.
Compliance with regulatory standards: Using couplings instead of traditional and unauthorized methods (such as heating or flaring the pipe end) is one of the main requirements of contractors and building engineers for obtaining project completion approval.
In this section, we will briefly become familiar with the manufacturing method of high-pressure couplings. The high-pressure coupling is a type of seamless coupling that, due to the absence of weld seams, possesses high mechanical strength and is capable of withstanding high pressures. This coupling, made of steel without the use of welding in its production, is considered one of the most popular options for connecting pipeline lines. Additionally, the high-pressure steel coupling is plated through a galvanizing process and becomes resistant to corrosion, rust, and oxidation.
The mechanical strength of seamless couplings against stresses, pressures, and earthquakes is very favorable and is suitable for exposed and underground connections. This type of coupling is produced in various types including weld couplings, reducing coupling connectors, reducer couplings, press couplings, flat couplings, threaded couplings, single-threaded couplings, and electrofusion seamless couplings, in diverse sizes for various pipes at normal, semi-heavy, and high-pressure levels.
The price of couplings is influenced by various factors. Different types and models of these fittings have specific features and applications, and each shows a different price. Their size and dimensions also affect the price, so that larger products usually cost more. The manufacturing brand also plays an important role in determining the price, whereby products from reputable brands are usually more expensive. The raw material quality is also important; steel, cast iron, or galvanized couplings have a higher price compared to plastic products. To receive the exact and up-to-date price of these fittings, using the services of our website is recommended.
Couplings are divided into various categories, and this classification is based on their connection type, material, and application.
Plain coupling: These types of couplings are designed in a cylindrical and hollow shape and are mostly made of cast iron. These couplings have internal threading and are used for joining two pipes of the same diameter.
Threaded couplings: The threaded coupling is actually considered a type of plain coupling, with the difference that there are internal and external grooves (threads) on both sides. This feature provides the possibility of creating various connections between different pipes.
Reducer coupling: Reducer couplings are used for joining pipes of different sizes. This type of coupling is especially very useful in swimming pool piping systems, industrial facilities, and liquid transmission networks.
Steel coupling: Steel couplings are used in pressurized systems due to their high strength. These couplings are divided into two types: welded steel and welded stainless steel, and are used for connecting steel pipes.
Brass coupling: Brass couplings are made of brass alloy and, due to their high resistance to corrosion, rust, and scaling, are a suitable choice for water supply systems and building facilities.
The steel conduit coupling enables the connection of two or more electrical conduits, the length of which is usually considered a maximum of 3 meters. These parts are typically made of strong metal so that, in addition to compatibility with electrical conduits, they can also show very good resistance to moisture. Knowing the features of electrical conduit couplings allows for easier and safer use, which we will discuss in more detail below.
Connection method: The connection of the coupling to steel electrical conduits is in the form of screwing. Therefore, to connect two pipes to each other, there is no need for welding, and they can be used in a straight path.
Material and raw materials: Electrical conduit couplings can be made of metal or polymer; however, since these couplings are specifically used for steel electrical conduits, they should preferably be purchased in steel material with a final galvanized coating.
Standard threads inside the coupling: Since the external threads of the electrical conduit must match the internal threads of the coupling to fully fit into each other, these threads are manufactured as standard. In terms of pitch, dimensions, and number of threads inside the coupling, there is full compatibility with steel electrical conduits.
Connection to same-size pipes: Metal couplings must definitely be connected to same-size pipes. In fact, since the cross-section of these couplings is the same on both sides, the two pipes or other parts that are connected to the coupling on both sides must necessarily be provided in the same size.
Quick connection: Opening and closing the coupling from steel electrical conduits is very fast. With the screw connection that exists for couplings, the pipe can be opened from the coupling whenever needed, or conversely, the pipe can be reinstalled on both sides of the coupling and a stable connection can be created.
In order to have a stable and strong connection between steel electrical conduits and electrical boxes, it is necessary to use a series of complementary parts. These parts are, in order, steel couplings and brass bushings, which have a relatively different structure. The brass models usually have a hexagonal wrench head, the base of which is threaded on the outside. To be able to install these conduits directly into a metal box, we must first screw a steel coupling onto the end of the conduit that has been threaded.
After that, we bring this conduit close to the electrical box and place the brass bushing from inside the box, precisely at the punched section or hole of the electrical box. The base that protrudes from the outside of the box, due to having external threads, is directly screwed onto the steel couplings. You can tighten these brass couplings from the inside using a wrench so that the conduits cannot come loose.
Manufacturing couplings with high-quality material compatible with electrical conduits plays a very important role in their performance. The resistant alloys used for these parts include steel and stainless steel. Galvanized plating is also usually applied to create a stronger coating resistant to moisture and acidic conditions, and this very issue results in creating safe connections in electrical conduit installations. The compatibility of the coupling material with the electrical conduit being used can increase the final stability. In this regard, metal couplings of the same material are usually used for metal electrical conduits.
To introduce the size of electrical conduit couplings, it is necessary to present several variables simultaneously. In fact, this information can provide buyers and individuals who want to carry out various projects with precise details. These variables include the following:
Size Based on PG
The size of couplings actually indicates what type of pipes and with what dimensions can be used on this type of fitting. As you know, pipe sizing varies and covers a wide range. Therefore, the sizes considered for these connecting parts, corresponding to the pipes, include dimensions PG11, PG13.5, PG16, PG21, PG29, PG36, and PG48. As you can see, these fittings support most electrical conduit sizes.
Thickness in Millimeters
Considering that most electrical conduit installation projects are carried out at the heights of structures, the issue of the lightweight nature of the pipes and their fittings becomes extremely important. The thickness considered for couplings is completely controlled, with the aim of keeping the part lightweight while also increasing its strength and resistance. Consequently, the thickness considered for these products is 1 and 1.5 millimeters. Couplings sized PG11 to PG21 have a thickness of 1 millimeter, and couplings sized PG29 to PG48 have a thickness of 1.5 millimeters.
Outer Diameter in Millimeters
The outer diameter of couplings varies from small to large sizes, but generally ranges from 20 millimeters for size PG11 to an outer diameter of 63 millimeters for size PG48. Naturally, as the size of the part increases or decreases, its diameter will also change.
Coupling Length in Millimeters
The length of these parts also increases with their size. The smaller type, which is size PG11, has a length of 30 millimeters, and the larger type, which is size PG48, has a length of 60 millimeters.
When purchasing these connecting parts and other parts used as inter-conduit fittings, be sure to pay special attention to the matter of size, because electrical conduits must be fully compatible and coordinated with their fittings in terms of dimensions.
Steel electrical conduit couplings are usually strengthened with galvanized coatings to provide high physical protection against chemical processes such as rust and corrosion, discoloration, or oxidation. In fact, this process provides the conditions for you to use these connecting parts without them undergoing structural deterioration. The type of coating applied to electrical conduit fittings is the hot-dip galvanization process.
In this process, after initial design and preparation, the parts are coated using molten zinc solutions. This smart measure can greatly increase the service life of the part. Of course, other processes such as cold galvanization are also performed on other types of electrical conduit connecting parts, but hot-dip galvanization is among the best methods used for strengthening metal.
At Rafi Industrial Group, in addition to the mentioned fittings, other parts such as brass bushings, conduit bodies, and other electrical conduit connecting parts have been prepared with the highest manufacturing quality for direct supply to customers and the market. You can contact our experts to receive pricing information and specialized consultation.
