Picking the Right Terminal Blocks for Your Industrial Work
This article looks at what you need to think about when picking terminal blocks for industrial use. We'll go over five main things: how much current they can handle, how they connect, where they'll be used, what certifications they have, and how easy they are to maintain and expand. The goal is to help you make your electrical systems safer and more reliable.
Why does picking the right terminal block matter so much?
Terminal blocks are key spots for sending current in things like industrial control systems, distribution boxes, new energy equipment, and automated production lines. If you pick the wrong ones, they can overheat, cause voltage drops, mess up signals, and even shut down your system. They might be small, but they're super important for keeping your electrical systems running smoothly.
I. Figure Out the Real Current You'll Be Using
A lot of projects just look at the rated current of a terminal block, but that's usually based on perfect lab conditions. Things get hotter inside a control cabinet, terminals are packed close together, and there's not much air flow, which all adds to the heat.
It's a good idea to add a 20%-30% buffer to the current capacity when you're choosing. So, if your actual current is 16A, you should go for terminal blocks rated for 20A or more.
II. Pick the Right Connection Type for Your Situation
1. Screw-type: Great for high current and power systems. They lock on really tight, but you need to check the screws every so often to make sure they're still tight.
2. Spring-type: Good for places with a lot of vibration. They keep constant pressure, don't need any upkeep, and are very stable.
3. Plug-in: Ideal for PCBs and modular systems. They're quick to install and easy to swap out.
III. Think About Where They'll Be Installed
If you're using them in places that are hot, humid, dusty, or have corrosive chemicals, go for tinned copper conductors and insulation that's rated UL94 V-0 for flame resistance. If needed, think about using a terminal system with good protection ratings.
IV. Check for the Right Certifications
If you're exporting or working on international projects, you'll usually need UL, CE, IEC, or RoHS certifications. If you don't use certified products, your project might get rejected or you could run into legal trouble.
V. Plan for Maintenance and Future Growth
When you're picking parts, don't just think about what you need right now. Also, think about future expansions, how easy they are to maintain, and how standardized they are. Modular designs can save you money on long-term operation and maintenance.
There's no one-size-fits-all terminal block. The best one is the one that fits your needs the best. By planning for enough current, picking the right connection type, using high-quality materials, and making sure you have the right certifications, you can really make your systems more stable and safe.
Terminal Block Overheating: What Causes It and How to Fix It
Overheated terminal blocks can cause stuff to break down or even spark a fire. This article will tell you why terminal blocks get too hot and what you can do to keep your electrical stuff safe and working like it should.
Why Should You Care About Overheating?
Terminal blocks are super important for connecting wires in places like control panels for factories, power systems, and automated production lines. If they overheat, it usually happens slowly, which can lead to bigger problems down the road.
What Makes Them Overheat?
1. Loose Wires:
If the wires aren't in tight, or if they're not prepped right, there's more resistance, and that means more heat.
What to Do:
Make sure everything is tightened just right.
For machines that vibrate a lot, use spring-type terminals.
Strip the wires to the right length.
Check the connections every so often, especially for important circuits.
2. Too Much Electricity:
Terminal blocks can only handle so much power but that's usually when everything's perfect. Things like how hot it is and how close everything is packed together can change how much power a terminal block can really handle.
What to Do:
Don't put as much power through the terminal block as it's rated for.
Make sure the air flows well in the control box.
Don't cram the terminals super close to each other.
Use bigger terminals.
3. Cheap Parts:
If the copper's not good, the coating is too thin, or the stuff around the wires doesn't resist fire, the terminal block won't move electricity well and can rust fast. This means it's more likely to overheat.
What to Do:
Use good copper or copper with a tin coating.
Use wire insulation that can resist fire.
Get stuff that's been approved by UL, CE, or RoHS.
How to Tell If Something's Overheating:
Use a heat sensor to look for hot spots.
Check if the connections are tight.
Watch how much power is going through.
Look for any weird colors or burn marks on the terminals.
Keep track of when you do maintenance on the equipment.
If you set things up right, use enough power margin, and use good parts, you can avoid equipment failing, lower safety risks, and keep your electrical systems running well for a long time.
How to choose the right terminal blocks for your project? We provide an in-depth analysis of five key factors: current and voltage, installation method, environmental adaptability, material structure, and certification standards, to help engineers and purchasing personnel make precise selections and reduce failure rates and maintenance costs.
I. Matching Electrical Parameters: Current, Voltage, and Safety Margin
1. Rated Current
When selecting terminal blocks, it's crucial to consider not only the nominal current of the equipment but also peak current, long-term load, cable cross-sectional area, and the impact of ambient temperature. It is recommended to leave a 20%-30% current margin to ensure stable long-term operation.
2. Rated Voltage
Different applications have different voltage requirements: low-voltage control systems typically use 300V, industrial power systems often use 600V or higher, and new energy systems can reach 1000V. Creepage distance and electrical clearance design should also be considered.
II. Wiring Method Selection: Screw-type or Spring-type?
1. Screw Terminal Block
Suitable for high-current applications, such as power distribution cabinets and industrial control boxes, but requires regular inspection to prevent loosening.
2. Spring Terminal Block
Suitable for automation control systems and vibrating environments, offering maintenance-free and vibration-resistant advantages.
3. Pluggable Terminal Block
Suitable for PCB connections and modular designs, facilitating installation and maintenance.
III. Environmental Adaptability: Do Not Underestimate the Working Environment
When selecting connectors, working temperature, protection rating, and vibration conditions must be considered. For high-temperature environments, high-temperature resistant nylon (PA66) material is recommended. In dusty or humid environments, attention should be paid to the IP protection rating and corrosion resistance.
IV. Material and Structural Design: Determining Long-Term Stability
High-quality terminal blocks typically use copper or tin-plated copper conductors and insulation materials that meet the UL94 V-0 flame retardant rating. Oxidation and corrosion resistance directly affect long-term operational safety.
V. Certification and Compliance: A Crucial Aspect for Export Projects
Common international certifications include UL, CE, TUV, IEC, and RoHS. For export projects, certification not only affects customs clearance but also relates to project acceptance and legal compliance.
When selecting components, engineers should consider ease of maintenance, modular expandability, and inventory standardization. Proper terminal selection not only improves system stability but also reduces long-term maintenance costs. Stable connections are fundamental to reliable system operation; although small, terminal blocks are crucial connecting components in electrical systems. Correct selection can reduce failure rates, extend equipment lifespan, and enhance overall brand reliability.
If you're an engineer, buyer, or seller, it's important to know about the different kinds of terminal blocks, Pitch, and where they're used.
I. Regular PCB Terminal Types
1. PCB Screw Terminals
These are strong and conduct electricity well, so they're good when you need a really reliable connection.
You'll often see them as 2-pin or 3-pole setups.
2. Pluggable PCB Terminals
These are made to be plugged in and out quickly, which makes fixing or switching things out easier.
They're common in industrial control boxes and automation systems.
3. Spring Terminals / Screwless Terminals
These are fast to install and don't shake loose easily, which is good for PCBs with a lot of wires packed close together.
II. What You Need to Know About PCB Terminal Spacing (Pitch)
The spacing between pins depends on how much current and voltage you need:
- 3.5mm / 3.81mm: For signals and when you don't need much current
- 5.0mm / 5.08mm: For industrial controls and power units
- 7.5mm / 7.62mm: For high current and voltage
III. Where Barrier Terminal Blocks Are Used
Barrier terminal blocks have more space between the connections and are safer.
They're usually found in power equipment, industrial control systems, and PCBs that handle a lot of power.
IV. Why Go with a Terminal Maker?
Buying straight from a terminal maker, factory, or provider means you get:
- Products that are always good quality
- The option to get things made the way you want
- Better prices
- Delivery you can count on, which is good for big orders
In conclusion:
From screw terminals to pluggable and insulated ones, picking the right terminal and spacing is key for a safe and well-performing system.
As a terminal factory, we give customers everywhere good terminal solutions.
In industrial control, power systems, automation equipment, and electronic products, terminal blocks are one of the most common and critical connectors.Choosing the right type of terminal block (such as pluggable PCB terminals, screw terminals, or spring terminals) not only affects wiring efficiency but also directly impacts system stability and future maintenance costs.
I. What are Pluggable PCB Terminal Blocks?
Pluggable PCB terminal blocks consist of two parts: a plug and a base, allowing for quick insertion and removal without the need for rewiring.
This type of terminal block is widely used in modular equipment and industrial control systems.
Advantages include:
- Fast installation and maintenance
- Reliable connection and stable contact
- Suitable for PCB mounting
- Available in various pitch sizes, such as 3.5mm, 3.81mm, 5.0mm, 5.08mm, 7.5mm, and 7.62mm
II. Screw Terminal Blocks: Characteristics
Screw terminal blocks secure wires using screws, resulting in a robust structure. They are one of the most common types of terminals in industrial applications.
Main Features:
- Secure wire fixation with strong tensile strength
- Suitable for medium to high current applications
- Low cost and high versatility
- Available in various configurations, including PCB mount screw terminals, 2-pin, 3-pole, etc.
III. Spring/Screwless Terminal Blocks
Spring terminal blocks use spring clips to secure wires, eliminating the need for screws and improving assembly efficiency.
Key Advantages:
- Fast wiring, reducing labor time
- Excellent vibration resistance
- Suitable for high-density PCB designs
IV. PCB Mounting Terminals and Barrier Terminal Blocks
In applications requiring high insulation distance and safety, barrier terminal blocks are widely used,
suitable for power supplies, power control, and industrial equipment.
V. How to Choose the Right Terminal Block?
When selecting a terminal block, it is recommended to focus on:
1. Terminal spacing (Pitch)
2. Current and voltage ratings
3. Wiring method (screw/spring/pluggable)
4. PCB mounting method
5. Frequency of future maintenance
Conclusion:
Whether it's pluggable terminals, PCB-mounted terminals, or spring terminals, choosing the right terminal solution can significantly improve system stability.
As a professional terminal manufacturer and supplier, we can provide customized PCB terminal solutions for our customers.
The torque of terminal blocks (specifically screw-type terminals) is the most critical and direct installation parameter affecting their connection reliability. It is not an isolated value, but a key control point in a precision engineering system. The following explains the relationship between the two, from principle to practice.
Core Principle: How is torque converted into a reliable electrical connection?
The physical chain of events can be simplified as follows:
Applied torque → Generation of clamping force (axial force) → Formation of contact pressure → Determination of contact resistance → Impact on long-term reliability
Torque (T): The rotational force applied during installation using a screwdriver or wrench, typically measured in Newton-meters (N·m) or centiNewton-meters (cN·m).
Clamping force (F): The axial compressive force generated between the wire, terminal block, and conductive strip as the screw is rotated and tightened. This is the core purpose of the torque.
The relationship is influenced by several factors: F ≈ k * T / d (where k is the overall friction coefficient, and d is the nominal diameter of the screw). The friction coefficient is a key variable and is greatly affected by the threads, washers, and surface condition of the wire.
Contact pressure (P): The actual pressure generated by the clamping force at the microscopic contact points. Sufficient contact pressure can:
Break through the oxide film: The surface of the conductor (usually aluminum or copper) has an insulating oxide film; high pressure can break this film, creating metal-to-metal contact.
Increase the contact area: Cause controlled plastic deformation of the conductor, increasing the effective conductive area.
Maintain stable contact: Resist loosening caused by vibration and thermal expansion and contraction.
Contact resistance (Rc): Contact pressure directly determines the magnitude of contact resistance. There is a critical pressure above which the contact resistance tends to stabilize at a very low value; below this value, the resistance increases sharply.
Low and stable Rc means: low power loss (P_loss = I² * Rc), low heat generation, high current carrying capacity, and good signal integrity.
The torque applied to terminal blocks is not simply a matter of "tightening," but rather a precise engineering control parameter. It is the bridge that transforms mechanical energy into a stable electrical connection.
Reliability formula: Reliable connection = Correct torque × Suitable wire × Standardized process × Matching terminal design.
Core understanding: The "correctness" of the torque directly determines the "stability" of the contact resistance, which in turn is crucial for long-term electrical reliability.
Ignoring torque control is equivalent to planting a time bomb in the connection point, a fault that will inevitably trigger over time.
Therefore, in any serious industrial, energy, or transportation sector, incorporating and strictly controlling wiring torque in process specifications is an essential measure to ensure the reliability of fundamental system connections.
Terminal blocks are one of the most basic and crucial components in electrical connections, with the core objective of achieving safe, reliable, and convenient wire connections.
I. Operating Principle
The basic principle of a 8 pole terminal block can be summarized as follows: through a mechanical structure and a conductor, it establishes a low-resistance, high-stability electrical path between conductors (such as wires), while ensuring a firm mechanical connection and preventing accidental contact.
This principle primarily relies on the following key points:
Electrical conduction: The core conductor of the terminal (usually copper or copper alloy) provides the main path for current flow. Its excellent conductivity ensures low energy consumption and low heat generation.
Mechanical clamping: Through screws, springs, or other mechanical devices, a substantial contact pressure (clamping force) is exerted on the inserted wire. This force serves two important purposes:
Destruction of oxide layer: The oxide film on the surface of the wire is non-conductive. A strong clamping force can crush this thin film, enabling true contact between metals.
Maintain contact: Prevent wire loosening caused by vibration, thermal expansion and contraction, or external force pulling, and maintain stable contact resistance.
Minimizing Contact Resistance: Ideally, the flow of current from a wire to a terminal and then to the next conductor should be as smooth as possible. Good design and clamping force can ensure that the resistance at the contact point is much lower than the resistance of the wire itself, thus preventing the point from becoming a "hot spot".
II. Design Structure
Despite the diverse shapes of wiring terminals, most of them consist of three basic components:
1. Conductive material: Typically, metals with high conductivity are used, such as brass, phosphor bronze, and copper alloys. Sometimes, they are plated with tin, nickel, or silver to enhance corrosion resistance, reduce contact resistance, and improve solderability.
Function: This is the core channel for current transmission. It is designed to connect reliably with wires and form an electrical interface with matching terminals or devices.
2. Insulating shell material for 8 position terminal block : Engineering plastics, such as polyamide (PA66, nylon), polycarbonate (PC), PET, etc., are commonly used. These materials exhibit good electrical insulation, mechanical strength, flame retardancy (such as UL94 V-0 grade), and heat resistance.
3. Clamping mechanism is the key part to distinguish different types of terminals. There are mainly the following mainstream designs:
a) Screw connection type
Structure: By rotating the screw, a metal pressure plate or conical nut is driven to directly compress the wire.
Advantages:
The connection is firm, with a large contact area and strong current-carrying capacity.
Suitable for connecting single-strand (solid) wires and multi-strand wires with wire lugs.
Disadvantages:
It may loosen in a vibrating environment, so regular inspection and tightening are required.
The connection speed is relatively slow.
For multiple thin wires, if a wire nose is not used, some copper wires may be crushed and broken during tightening.
b) Spring connection type (cage spring/compression spring type)
Structure: Utilize a pre-tensioned V-shaped or other shaped spring leaf. Insert a straight screwdriver into the operating hole to open the spring. After inserting the wire, withdraw the screwdriver, and the spring will rebound, firmly pressing the wire against the internal conductive strip.
Advantages:
Vibration resistance: The continuous pressure of the spring can compensate for the looseness caused by thermal expansion and contraction and vibration, making it very reliable.
Quick wiring: No need to twist screws, greatly improving wiring efficiency.
Suitable for multi-strand wires and thin wires with casings.
Disadvantages:
Strong dependence on tools (requires a screwdriver of a specific size).
The current-carrying capacity is generally slightly lower than that of screw connections of the same size (but it is sufficient in most cases).
c) Direct plug-in connection
Structure: This is a simplified form of spring connection. It usually has a small hole, into which a stripped and untreated solid wire is directly inserted with force. The internal spring mechanism will automatically clamp the wire. To release the wire, you need to press the release button next to it.
Advantages:
It is extremely fast and convenient, and the terminal block 10 pin can be made without any tools.
Disadvantages:
It is usually only applicable to solid conductors.
The current-carrying capacity and wire diameter range are limited.
d) Insulation displacement connection
Structure: Inside the terminal, there are sharp V-shaped metal contacts. When a unstripped wire is pressed firmly into the designated position, the sharp contacts pierce through the insulation and make direct contact with the internal metal conductor.
Advantages:
No need to strip the wire, saving time and effort, and avoiding problems caused by improper wire stripping length.
The connection is fast and reliable.
Disadvantages:
There are strict requirements for the specifications of the wires and the thickness of the insulation.
It is commonly used in signal current applications such as communication, data networks (such as RJ45 connectors), and home appliances.
III. Main Types and Applications
According to application scenarios, terminal blocks mainly come in the following forms:
PCB terminal block: soldered onto a printed circuit board, used to connect external wires to the circuit board.
DIN-rail terminal blocks: They can be clipped onto standard DIN rails and are widely used in industrial control cabinets and distribution boards, facilitating modular installation and maintenance.
Barrier terminal block: 12 position terminal block Equipped with plastic partitions, it is commonly used in high-voltage and high-current applications such as power distribution, effectively preventing short circuits between different polarities.
Socket terminal: used for connecting devices that require frequent plugging and unplugging.
IV. Design Considerations and Selection Key Points When designing or selecting terminal blocks, the following factors must be considered:
Current and voltage ratings: These are the most crucial parameters, which must meet or even exceed the maximum demand of the circuit, while leaving a margin.
Wire type and specification: Is it a single-strand wire or a multi-strand wire? What is the wire diameter (AWG or square millimeter)? This determines which clamping mechanism should be selected.
Environmental conditions: Is it exposed to high vibration, high temperature, high humidity, or corrosive environments? This affects the selection of materials (such as housing plastics, plating layers) and connection methods (such as spring connections for better vibration resistance).
Safety certification: Whether it is necessary to comply with safety standards in specific regions, such as UL (United States), UL (Canada), CE (Europe), VDE (Germany), etc.
Number of wires and spacing: How many wires need to be connected? Does the spacing (pitch) between terminals meet the requirements for electrical clearance and creepage distance?
Summary
Although terminal blocks are small components, they are the "joints" of the electrical system. Their working principle is based on reliable mechanical clamping to achieve low-resistance electrical contact. Their design structure revolves around three major elements: conductors, insulating shells, and clamping mechanisms. For different application needs, various clamping technologies such as screws, springs, direct insertion, and insulation displacement have been derived. Proper selection and installation are the foundation for ensuring long-term stability and safe operation of the entire electrical system.
This is a highly practical and crucial issue. Selecting the right terminal block for equipment is key to ensuring safe, reliable, and long-lasting electrical connections.
This a clear and systematic selection guide, which you can follow to find the most suitable terminal for your equipment.
Step 1: Clarify Requirements — Understand What You Need
1.Current load (amperes, A)
This is the most important parameter. The terminal must be able to safely carry the maximum continuous current in the circuit and leave appropriate margin (usually it is recommended to choose a terminal with a rated current 20-30% higher than the actual maximum current).
The consequences of incorrect selection: Overloading can cause terminals to heat up, melt, and even trigger fires.
2.Voltage level (volts, V)
The terminal needs to be able to withstand the operating voltage and possible transient overvoltage in the circuit.
Common voltages include low voltage (such as 12/24/48VDC), industrial control voltage (110/220VAC), or higher voltage.
3.Wire specifications (wire diameter, mm ² or AWG)
The terminal must perfectly match the cross-sectional area of the wire. Too much pine can cause poor contact and overheating; If it is too tight, it will damage the wire.
Please accurately measure the square of the wire (mm ²) or the American Wire Gauge (AWG) value.
4.How many wires need to be connected?
Single core wire vs multi stranded wire: Some terminals (such as pin crimping terminals) are only suitable for multi stranded wires, while wiring blocks can accommodate both, but it is sometimes recommended to use pin terminals for multi stranded wires.
Number of wires: Is it a 1-to-1 connection, a 1-to-many connection, or is it necessary to connect multiple wires to one point?
5.How is the usage environment?
Temperature: Is the ambient temperature very high (such as near the engine) or very low?
Humidity: Is it used in a damp or humid environment?
Vibration: Is the equipment in a vibrating state (such as vehicles, machine tools)? Terminals with anti vibration design are required for vibration environments.
Chemical substances: Will they come into contact with oils, solvents, or other chemicals?
Outdoor use: Do you need UV protection, waterproof and dustproof (refer to IP rating)?
Step 2: Key Selection Parameter Checklist
Match the requirements of the first step with the specifications of the terminals:
Parameters
Parameters
Terminal specification sheet
Electrical
Current (A)/Voltage (V) Rated
Current/Voltage
Mechanical
wire specification (mm ²/AWG)
applicable wire range
Screw torque (if any)
Recommended torque (N · m)
Connection type (screw, spring, plug)
wiring technology
Environmental
temperature
operating temperature range
Protection level IP
rating (such as IP20, IP67)
Certification requirements (export)
UL, cUL, VDE, T Ü V, etc
Material
Corrosion resistant and conductive conductor material
usually copper, with tin/nickel/silver plating on the surface
Insulation and flame retardant
insulation material (usually PA66 nylon, with UL94 V-0 flame retardant rating)
Step 3: Practical suggestions and summary
Quality priority: Do not use inferior terminals of unknown origin. They may use inferior materials (such as iron instead of copper), thin coatings, and non flame retardant insulation materials, which are serious safety hazards.
Matching tool: For crimping terminals, it is strongly recommended to use professional crimping pliers. Using mismatched tools or pliers for crimping cannot guarantee the quality of crimping, which can easily lead to poor contact.
Sample testing: Before bulk procurement, if conditions permit, a small amount of samples can be purchased for testing. Check its clamping force, conductivity, and temperature resistance.
Seeking professional help: If unsure, you can ask us for help ,NingBo HongYi Electronic Co., we will give you a professinal answer.
To summarize, the process of finding the correct wiring terminals for a device is:
Clear requirements (current/voltage/wire diameter/environment) → Verify parameters (rated value/material/certification) → Practical verification (tools/samples)
By following this process, you can find the safe and reliable "right terminal block" for your device.
This is an excellent question that directly addresses the core of electrical system reliability. Why terminal block quality so important?because its the key for integrity, stability, and safety of the "conductive circuit." We can delve into this matter from several dimensions: materials, design, manufacturing process, and practical implications.
1. Materials: The Physical Basis of Conductivity
Conductivity is primarily determined by the material. High-quality terminal blocks are made from materials with excellent conductivity and undergo necessary surface treatments.
Main material (conductive sheet):
Premium Options: High-purity oxygen-free copper (e.g., TU1) or copper alloys (e.g., brass, phosphor bronze). These materials exhibit low resistivity and excellent conductivity, while phosphor bronze also offers superior elasticity and fatigue resistance, ensuring long-term contact pressure maintenance.
Low-quality materials: Using recycled copper with high impurities, copper-clad aluminum, or even iron coated with copper. These materials exhibit high electrical resistance, severe heat generation, and are prone to corrosion, posing significant safety hazards.
Plating layer: Key corrosion-resistant and contact-enhancing layer.
Tinning: The most common method, with moderate cost, effectively prevents copper substrate oxidation while maintaining excellent solderability and contact.
Silver plating: Offers the best conductivity and strong oxidation resistance, commonly used in applications requiring extremely low contact resistance or high-frequency signals (though silver can sulfidize in sulfide environments).
Nickel/Plated Gold: Excellent wear and corrosion resistance, suitable for high reliability, frequent plugging and unplugging, or harsh environments.
Low-quality products: thin and uneven coatings with poor adhesion, which wear or oxidize quickly, leading to a sharp increase in contact resistance.
2. Design and Craftsmanship: Transforming Material Properties into Reliable Connections
Good materials require good design and craftsmanship to achieve.
Contact Design:
Pressure and Area: The spring or screw structure must provide sufficient, stable, and uniform contact pressure. Insufficient pressure results in high contact resistance, while excessive pressure may cause plastic deformation of the cable or spring, leading to failure.
Contact point protection: The design should minimize the erosion of contact points by environmental factors (dust, moisture, corrosive gases).
Structural Strength and Insulating Materials:
Insulated housing: Must be made of flame-retardant, high-temperature-resistant, and high-CTI (Comparative Tracking Index) engineering plastic (e.g., PA66+GF). Inferior plastics are prone to aging, deformation, or even combustion, which can cause short circuits or fires.
Mechanical strength: Structures such as clips, guide rail grooves, and screw mounting seats must be robust and capable of withstanding stresses from installation, operation, and vibration.
Process consistency:
Precision Machining: Ensure consistent dimensions and tight tolerances at every contact point.
Reliable fasteners: The strength of screws, thread accuracy, and anti-loosening designs (such as screws with saddle washers) are crucial.
Conclusion: Terminal blocks are the "gatekeepers" of system safety
In modern electrical and control systems, although terminal blocks are inconspicuous passive components, they undertake multiple key functions such as current transmission, signal connection, circuit isolation, and physical fixation.
High quality terminal block: Like a loyal "goalkeeper", it ensures low loss, zero distortion, and high reliability of electrical energy and signals, resists environmental erosion and mechanical stress throughout the entire life cycle of the equipment, and is the cornerstone of safe, stable, and efficient system operation.
Low quality terminal block: It is a hidden time bomb in the system. The small cost savings it saves are completely insignificant compared to the potential costs of equipment damage, production downtime, data loss, and even personal safety accidents.
Therefore, when choosing a terminal block, it must not be regarded as a simple "wiring tool". The strict requirements for its materials (conductivity and coating), design (contact and insulation), and process (consistency) are the basic guarantees for the investment and personal safety of the entire electrical system. Always adhere to selecting products that comply with international standards (such as UL, IEC, VDE) and come from reliable manufacturers, which is the wisest choice.
Using Proper Terminal Block is a crucial step in improving electrical performance, involving aspects such as connection reliability, signal integrity, and power transmission efficiency. The following is a systematic guide to selection and application:
I. Clearly Define Core Electrical Performance Indicators
Contact Resistance: Low and stable contact resistance reduces heat generation and energy loss.
Current Carrying Capacity: Terminals must withstand the rated current (considering instantaneous peak values).
Voltage Drop and Temperature Rise: Excellent design minimizes voltage loss and heat accumulation.
Insulation and Dielectric Strength: Prevents leakage and breakdown (especially in high-voltage environments).
Signal Integrity: High-frequency signals require impedance matching and shielding to prevent interference.
Mechanical Stability: Resistance to vibration and loosening ensures reliable contact over the long term.
II. Key Selection Factors for Terminals
1. Material Selection
Conductor Material:
High conductivity: Oxygen-free copper and copper alloys (such as brass and phosphor bronze) are the mainstream choices.
High current/high temperature environments: Consider silver plating or aluminum material (for lightweight applications).
Insulation Material:
General purpose: PVC, nylon (low cost).
High temperature/flame retardant: PTFE (Teflon), PEI, PPS.
Plating Treatment:
Anti-oxidation/improved conductivity: Silver plating (optimal conductivity), gold plating (corrosion resistance, suitable for high frequencies), tin plating (low cost, but beware of "tin whiskers").
Environmental adaptability: Salt spray environments require thick plating or gold/nickel composite plating.
2. Structural Design
Crimping vs. Soldering:
Crimping terminals: Requires specialized tools, offers high consistency, good vibration resistance, and is suitable for mass-produced wire harnesses.
Soldering terminals: Manual operation is prone to cold solder joints; wave soldering/reflow soldering is recommended.
Contact Surface Design:
Wire spring structure (multi-contact): Redundant contact, excellent vibration resistance.
Double helical spring structure: High retention force, used in high-vibration environments (such as aerospace).
Locking Mechanism:
Snap-fit and threaded locking (e.g., MIL-DTL-38999 military-grade connectors) prevent loosening.
3. Matching with the Cable
Cross-sectional area matching: The terminal specifications must strictly correspond to the wire gauge (e.g., AWG standard).
Crimping quality: Use professional crimping tools to avoid over-crimping (metal fracture) or under-crimping (insufficient tensile strength).
Insulation support: Terminals with insulation sleeves can prevent stress fractures.
If you are looking for a good pcb terminal blocks manufacturers,you may considering
the variety kinds of terminal block :Pluggable Terminal Blocks, Screw Terminal Blocks , Barrier Terminal Blocks , and Screwless Terminal Blocks.Now let's talk about the Differences Between them.
Pluggable Terminal Blocks:Normally it has two parts ,male parts and female parts,and these two
parts can be pluggable. The male parts for welding to the pcb board,the female parts is for connecting wire.And other kinds of terminal block only one part. And for the pitch ,it has
2.5,3.5,3.81,5.0,5.08,7.5,7.62mm pitch,for the pole,it has from 2pole to 24pole, and many customer will choose 5 position terminal block .
Screw Terminal Blocks: the most traditional and common type of terminal block,By rotating the screw,the downward pressure of the screw compresses the wire tightly into the conductive slot,achieving electrical connection.
Barrier Terminal Blocks :it can be seen as a "reinforced version of screw terminal block".Its structural feature is the presence of on or more raised metal barriers that separate the wiring holes,increase the creepage distance,and provide stronger wire clamping space.
Screwless Terminal Blocks:means no screws,use the continuous pressure of the spring to clamp the wire.When wiring,a straight handle screwdriver is usually used to insert and push open the spring,then insert the wire,and after pulling out the screwdriver,the spring returns to its original position to tightly clamp the wire,
Suggestions:
1.Need frequent plugging and modular maintennance----choose Pluggable Terminal Blocks
2.limited budget,universal application,and no worries about vibration and wiring speed----choose Screw Terminal Blocks
3.Dealing with high voltage and high current,with extremely hight requirements for safety and reliability-------choose Barrier Terminal Blocks
4.Pursuing the highest wire efficience,with scenarios mostly iinvolving small and medium currents,and hoping for good vibration resistance----Screwless Terminal Blocks
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