What are the materials of the terminal block

The material choice of the terminal block is very important, because it directly affects the electrical performance, mechanical strength, service life and safety of the product. The basic structure of the terminal block consists of an insulating housing and one or more metal terminals. Metal terminals are used to clamp the wires, while the insulated housing ensures electrical safety and prevents short circuits. The following INFINITECH will introduce the commonly used materials for these two parts:

Metal terminal material

As the basic material, electrolytic copper is widely used because of its good electrical conductivity and high corrosion resistance. The conductive part is usually made of red copper (high purity copper), while screws and wire frames may be made of brass (H62). H62 brass is an alloy containing about 62% copper and the remainder zinc, with good mechanical properties and workability. Brass is not as conductive as pure copper, but is sufficient in some applications. In order to improve the corrosion resistance and electrical properties of metal terminals, electroplating is usually performed on the metal surface. Common coating materials include tin (Sn), nickel (Ni), silver (Ag) and gold (Au).

Insulating housing material

Polycarbonate, commonly known as bulletproof glue, has the characteristics of high strength, high toughness, heat resistance, flame retardant and so on. Suitable for applications requiring high mechanical strength and temperature resistance. Urea resin, also known as electric jade powder, used to be used as insulation materials. Performance is slightly worse than PC, suitable for low-end products. ABS is a kind of general engineering plastic with good impact resistance, chemical resistance and formability. Suitable for a variety of applications. Poly (butylene terephthalate) has good heat resistance and electrical insulation. Suitable for high temperature and applications requiring good electrical performance. Polyamide 66 (PA66) has high compressive strength and good temperature resistance. Suitable for environments requiring high strength and chemical resistance. Other plastic materials may be used according to special requirements, such as polysulfone (PSU), polyether ether ketone (PEEK) and other high-performance engineering plastics. When selecting terminal block materials, factors such as application environment, cost, and performance requirements should be considered. For example, in high temperature environments, it is necessary to choose materials with good heat resistance; In humid environments, the material needs to have good moisture resistance

What is the maximum current carrying capacity of the terminal block

The maximum current carrying capacity of a terminal block depends on a variety of factors, including wire size, terminal design, environmental factors, and manufacturer specifications. In general, larger wires can carry more current, and the design of the terminals (such as spring and screw) affects their heat dissipation capacity and contact resistance, which in turn affects the current carrying capacity. Environmental factors such as temperature and humidity also have an impact on current carrying capacity. Manufacturers typically provide specific current ratings for terminal blocks, such as VH3.96mm 2P terminals with an electrical current rating of 7.0A AC(rms), while cord end terminals (4-4 models) can carry up to 380A of current and are suitable for high-power industrial applications. To ensure safety and avoid overheating and damage, it is recommended to select a terminal block with a rated current of at least 150% of the expected maximum current of the system. In addition, the material of the terminal block and its surface treatment also affect its current carrying capacity. When selecting a terminal block, be sure to refer to the specific data and specifications provided by the manufacturer to ensure suitability and safety.

Type of terminal block

There are many types of terminal blocks, common ones are:

Screw terminal: Use screws to secure the wire to the metal terminal. Suitable for most applications and easy to install and maintain.

Push-button terminals: The clamp is opened by pressing a button, and the wire is fixed by releasing the button after insertion. Easy and fast, no tools required.

Push-in terminals: The wire can be inserted directly into the housing, and the internal mechanism automatically clamps the wire. Fast and easy, no tools required.

Pluggable terminals: For applications that require frequent connections and disconnections. Provides the function of quick connection and disconnection.

Fence terminals: Usually used for PCB installation, also known as wire-to-board terminal or European terminal. Suitable for fixing wires to printed circuit boards.

Spring terminals: Use the pressure of the spring to clamp the wire and complete the connection without tools. Suitable for quick installation and easy maintenance.

Rail terminals: Designed for applications mounted on standard DIN rails. Easy to install in the control cabinet.

Straight-through terminals: Used to connect wires directly without requiring additional fixtures.

Isolation tape terminal: Multiple terminals are connected in series through the isolation tape to form a continuous connection path. Suitable for applications requiring long distance connections.

Through-wall terminals: Used to pass through a partition wall or partition to transmit signals from one side to the other. Suitable for applications requiring electrical isolation.

These types of terminal blocks have their own characteristics and scope of application, and the selection should be determined according to the specific application requirements. For example, push-in or spring-type terminal blocks are available for applications requiring quick installation and maintenance; For applications that require high reliability and durability, threaded terminal blocks may be a better choice.

Common applications of terminal blocks

The application range of terminal blocks is extremely wide, covering almost all areas that require electrical connections, such as:

It is used to connect various sensors, actuators and other electrical components in the electrical systems of vehicles such as cars, trains and ships.

Used for electrical connection of temperature controllers, fans, heaters and other devices in building automation systems.

Electrical connections for office equipment such as printers, copiers, scanners, etc.

It is used to connect power systems such as uninterruptible power supply (UPS) and switching power supply.

Electrical connections in laboratory and industrial measuring equipment.

Electrical connections in telecommunications infrastructure such as communication base stations, switches, routers, etc.

Signal transmission and electrical connections in factory automation control systems.

Electrical connections in paper making and printing equipment.

Electrical connections in textile machinery.

Electrical connections in various mechanical devices.

Electrical connections in electronic product lines.

Electrical connections in automotive production lines.

Electrical connections in plastic processing equipment such as injection molding machines and extruders.

Electrical connections in power plants, substations, etc.

Including solar, wind and other renewable energy equipment in the electrical connection.

Electrical connections in food processing equipment.

Electrical connections in medical devices.

Electrical connections in water treatment facilities.

Electrical connections in environmental monitoring equipment.

Electrical connections in urban infrastructure such as street lights and traffic lights.

Electrical connections in boiler systems.

Electrical connections in the grid.

Electrical connections in large commercial buildings, office buildings, schools, etc.

What are the brands of the terminal block

There are many terminal block brands on the market, some well-known brands include:

• Altech Corporation

• American Electrical Inc.

• Amphenol Anytek

• Amphenol ICC (FCI)

• Amphenol PCD

• ASI-Ez

• Assmann WSW Components

• Belden Inc.

• Brady Corporation

• Bud Industries

• Bulgin

• c3controls

• Cinch Connectivity Solutions

• CNC Tech

• Conta-Clip, Inc.

• CUI Devices

• Curtis Industries

• Delta Electronics/Industrial Automation

• DFRobot

• E-T-A

• Eaton - Bussmann Electrical Division

• Eaton - Electronics Division

• Eclipse Tools

• Woertz

These brands not only provide high-quality products, but also have a perfect technical support and service system. It happens that these brands of terminal blocks are sold on the INFINITECH component purchasing mall.

How to choose the right terminal block

There are several factors to consider when choosing the right terminal block:

First determine the level of current required for your application and select a terminal block that can withstand that current. In general, the current carrying capacity of the terminal block should be higher than the expected maximum operating current.

Verify that the voltage level of the terminal block meets the requirements of your application.

The voltage level must be greater than or equal to the operating voltage of the system.

Select the terminal block according to the size of the wire you will be connecting.

Ensure that the terminal block can accommodate the cross section of the wire and that the connection is stable and reliable.

Consider which type of connection is best for your application. Common connection methods include screw type, spring type, push-in type, etc.

Consider the working environment of the terminal block, such as temperature, humidity, and corrosive gases. Choose materials and designs that can adapt to specific environmental conditions.

Determine the mounting method of the terminal block, such as DIN rail mounting, panel mounting, PCB mounting, etc.

Ensure that the terminal block has sufficient mechanical strength to withstand the expected load and vibration.

If the terminal block needs to be exposed to the outside environment, consider choosing a product with the appropriate level of protection to prevent dust and moisture from entering.

Verify that the insulation properties of the terminal block meet safety standards, especially if the terminal block is located in an area where there may be a risk of electric shock.

Verify that the terminal block complies with relevant international or regional standards, such as UL, CE, and RoHS. Select a cost-effective terminal block based on your budget.

Considering that the terminal block may need to be replaced or maintained in the future, choose a product that is easy to install and remove.

Select brands and suppliers with good market reputation to ensure product quality and service support.

For special applications, such as extreme temperature environments, explosion-proof environments, special consideration needs to be given to the special design and material of the terminal block.

What is the maintenance method of the terminal block

In order to ensure the long-term stable operation of the terminal block, regular maintenance is necessary:

1. Cleaning: Regularly clean the surface of the terminal block to remove dust, grease and oxides. This can be achieved by using a soft cloth and an appropriate cleaning agent. For automotive battery terminals, a lubricant or anhydrous alcohol/ethanol can be used to clean the terminal surface to remove oxides and rust.

2. Check the connection: Periodically check whether the connection between the terminal block and the wire is tight to ensure that it is not loose. For screw-secured terminal blocks, the screws can be slightly tightened to ensure a secure connection.

3. Lubrication: For some terminal block components that require lubrication, such as spring mechanisms, appropriate lubricants can be used to maintain their flexibility and reduce wear. For some special mechanical structures, such as the main speed bearing in the terminal machine, it is necessary to regularly fill lubricants such as butter.

4. Anti-corrosion treatment: For vulnerable environments, anti-corrosion measures can be taken, such as using anti-corrosion coatings or sealing terminal blocks.

5. Check the insulation material: Check the insulation material of the terminal block for cracks or signs of aging, and replace it if necessary.

6. Check contact points: Check contact points of terminal blocks regularly for wear or corrosion, and clean or replace them if necessary.

7. Environmental control: Ensure that the terminal block is in a suitable working environment to avoid the influence of high temperature, humidity or corrosive gases.

8. Regular inspection: According to the frequency and importance of the use of the terminal block, develop a regular inspection plan to discover and solve the problem in time.

9. Maintenance records: Maintain maintenance records, including maintenance dates, operations performed, and problems found. These records help you track terminal status and predict future maintenance requirements.

10. Follow the manufacturer's guide: Refer to the maintenance manual or guide provided by the terminal block manufacturer and follow the recommended maintenance procedures.

For specific types of terminal blocks, such as bus terminals, it is also necessary to check the contact between the bus and the long conductor, and carry out the necessary cleaning and maintenance. In addition, for large or complex electrical systems, it may be necessary to consider the overall system maintenance strategy to ensure that all related equipment is properly maintained.

What is the difference between a terminal block and a terminal box

Terminal block

A terminal block is an electrical connector used to connect wires or cables. They are usually mounted on control panels, switchboards, or machine equipment. It is mainly used for fixing and connecting wires to provide reliable electrical connections. The terminal block allows connections between wires or between wires and electrical components. The structure comprises an insulated housing and one or more metal terminals. Metal terminals are used to clamp the wires, while the insulated housing ensures electrical safety and prevents short circuits.

Common types include screw type terminal block, spring type terminal block, push-in terminal block, and in-line terminal block. Its application can be seen in industrial automation, building automation, and various electrical engineering.

Junction box

A junction box is a closed container used to protect electrical connections. It provides a safe environment for wire connection points. It is mainly used to protect wire connections from external environmental factors, such as dust and moisture.

The junction box may contain terminal blocks or other types of electrical connections. Its structure consists of a closed shell, usually made of metal or plastic. May contain terminal blocks, screw posts, or other types of connectors.

It is commonly used for indoor and outdoor electrical installations, outdoor lighting, temporary electrical wiring and any application where electrical connections need to be protected in harsh environments.

Differential summary

• The terminal blocks are mainly used to provide electrical connection points, while the junction boxes mainly provide an enclosed environment to protect these connection points.

• The terminal block is one of the components inside the junction box, which is the container that protects these components from the external environment.

• Terminal blocks are used more in internal electrical systems, while junction boxes are widely used outdoors or where additional protection is needed.