What Is The Difference Between Barrier Strips And Terminal Strips?

Barrier strips and terminal strips are both commonly used electrical components for connecting multiple wires. While they serve a similar function, there are some key differences between the two that is important to understand when selecting the right option for an electrical project.

The purpose of this article is to provide a detailed comparison of barrier strips vs terminal strips. We will examine the materials, intended applications, number of connections, cost considerations, and safety factors of each type. Understanding the capabilities and limitations of these wire connector blocks is crucial for both electrical engineers and hobbyists alike when designing and building electrical circuits and control panels.

What are Barrier Strips?

Barrier strips are insulating devices used to connect and organize multiple wires/cables. According to the Vocabulary Dictionary, barrier strips are “a junction unit for connecting 2 cables without the need for plugs”, which act as a barrier between connections (source). They allow the connection of electrical cables without splicing or soldering wires together.

Barrier strips typically consist of a plastic or ceramic body with metal screw terminals. The body provides insulation between the terminals to prevent accidental contact and short circuits. Wires can be securely attached to the terminals using screws. The terminals are also color coded to allow for easy circuit identification.

Common applications of barrier strips include connecting multiple wires in electrical boxes, power distribution, and signal routing for telecom and electronics. They enable organized cable management and provide protection to prevent short circuits. Overall, barrier strips are versatile wiring accessories used to safely distribute and direct electrical connections.

What are Terminal Strips?

Terminal strips are another type of insulating device used to connect wires/cables. They provide a structured array of terminal points arranged as a strip, each with a corresponding number or label. This allows multiple wire connections to be organized and documented efficiently.

Terminal strips are typically made of plastic or ceramic and contain metal screws, clamps, or spring clips to attach wires. They provide protection against electric shock and enable simple installation of wires. Some key features of terminal strips include:

Terminal blocks or connector blocks are types of terminal strip designs that use rows of metal plates with screw holes or spring clips to connect wires. DIN rail mounted terminal blocks snap onto a standard DIN rail for mounting multiple blocks in an assembly.

Compared to barrier strips, terminal strips have more individual connection points and allow for greater wiring density. They are also more flexible since wires can be added, removed, or rearranged in modular design terminal blocks. The labeled or numbered terminals enable identification and documentation of complex wiring.

Terminal strips are commonly used for making connections to electrical control systems in industrial settings and commercial buildings. They are also found in products like appliances, instruments, and HVAC equipment to connect internal components.

Source: https://www.electricaleasy.com/2018/03/terminal-block-types.html

Key Differences

There are some notable differences between barrier strips and terminal blocks when it comes to construction materials, intended applications, and number of connections:

Construction Materials: Barrier strips are typically made of plastic, while terminal blocks can be made of various materials like plastic, ceramic, or metal. Terminal blocks that need to withstand high temperatures may use ceramic materials. According to Eaton, metal terminal blocks are best for rugged industrial applications.

Intended Applications: Barrier strips are common in electronic prototyping and hobbyist applications, while terminal blocks are more heavy duty and used in industrial control panels and motor connections. Terminal blocks are rated for higher amperages and can accept larger wire gauges. As noted by RealPars, terminal blocks are designed to be mounted on DIN rails.

Number of Connections: Barrier strips typically allow for 10-20 connections, while terminal blocks may allow for hundreds of connections depending on the size. For very high density connections, terminal blocks are the better choice over barrier strips. PCM Cable points out that IEC-style terminal blocks are designed for wave soldering many connections.

Materials

Barrier strips and terminal strips are both made from insulating materials to prevent electrical conduction between the connections. However, there are some key differences in the materials used:

Barrier strips are typically made from more rigid insulating materials like phenolic resin, nylon, PBT (polybutylene terephthalate) or melamine. These tough plastics allow barrier strips to maintain their shape and prevent warping from heat or tight connections.

Terminal strips on the other hand use softer insulating materials like PVC (polyvinyl chloride). PVC allows terminal strips to have some flexibility and increased impact resistance compared to more rigid plastics. However, PVC is also more prone to deforming from heat or pressure.

The rigid materials in barrier strips make them suitable for applications where solid physical connections are needed. Terminal strips offer more flexible options but may not hold up as well to extreme temperatures or tight clamping forces.

Overall, the type of insulating material impacts the durability and performance of each component. Rigid barrier strips excel where strength is required while flexible terminal strips adapt better to changing needs.

Applications

Barrier strips and terminal strips are suited for different types of applications based on their power handling capabilities. Barrier strips have been designed for higher voltage and higher current applications where large amounts of power need to be distributed. As shown on the TE Connectivity website, barrier strips can handle up to 600V and 100A in some models. This makes them well-suited for power distribution in industrial equipment, large appliances, machinery, and other high power applications.

In contrast, terminal strips are designed for lower voltage, lower current applications where less power is required. As the Cuidevices blog discusses, terminal strips generally handle under 300V and 15-30A maximum. This makes them better suited for signal and data transmission in electronics, alarm systems, low voltage lighting, and other applications where high power capacity is not needed.

So in summary, barrier strips are preferable for high power AC/DC applications while terminal strips are recommended for lower power signal and data transmission applications.

Number of Connections

Barrier strips allow for more wire connections than terminal strips. As Eaton explains, “Screw clamp terminal blocks are designed for higher density wiring. In the same footprint, you can fit more terminations with a screw clamp than a traditional barrier strip.” (Eaton)

Terminal strips have limitations on the number of wires that can be connected. Most terminal strips max out at around 12-22 connections. Barrier strips on the other hand can accommodate 50 or more wire connections in the same space. This makes them preferable for applications that require connecting a high number of wires.

The larger size and screw clamp mechanism of barrier strips allows multiple wires to be safely inserted into each connection point. So they can pack more connections into a compact form factor. For projects or installations with many wired components, barrier strips are the better choice.

Cost Comparison

One of the primary differences between barrier strips and terminal strips is cost. Barrier strips tend to be more expensive than terminal strips.

Barrier strips are made of higher quality materials like ceramic or plastic and are designed for heavy-duty applications. The sturdy construction comes at a price premium. According to ElecDirect, barrier strips can cost $5-10 for a small package while terminal strips may only cost $1-2 for a similar quantity.

Terminal strips are mass produced with cheaper materials like phenolic resin which brings down the manufacturing costs. While terminal strips may not be as durable, they provide an economical solution for basic wiring needs. The lower price point allows terminal strips to be widely used for light commercial and residential wiring.

For heavy duty electrical applications where reliability is critical, paying more for higher quality barrier strips is worthwhile. But for simple home wiring jobs, inexpensive terminal strips get the job done.

Safety Considerations

When working with electrical connections, safety should always be the top priority. Both barrier strips and terminal blocks need to follow proper wiring practices to prevent electrical hazards.

Terminal blocks are typically certified to meet safety standards such as UL, CSA, VDE, or IEC. For example, many terminal blocks comply with UL 1059, which tests for high voltage breakdown, insulation resistance, temperature rise, and mechanical strength (Source). Terminal blocks should be selected with a voltage and current rating well above the expected system loads.

Barrier strips provide isolation between terminals to contain stray wire strands and prevent shorts. They should be mounted securely and wired correctly with no loose strands touching other terminals. Wires should be prepared properly by stripping just enough insulation without nicking the conductor.

For both terminal blocks and barrier strips, wires should be tightened to the torque specifications and not overtightened. Proper ferrules or lugs matched to the terminal screw size should be used when possible. Wiring should be done with power off for safety.

By following the proper wiring methods and using certified components, barrier strips and terminal blocks can provide safe and reliable electrical connections.

Conclusion

In summary, the key differences between barrier strips and terminal strips are:

• Materials – Barrier strips are made of plastic while terminal strips are made of metal.
• Number of connections – Barrier strips allow for multiple connections while terminal strips are limited to one wire per screw.
• Cost – Barrier strips are generally less expensive than terminal strips.
• Safety – Terminal strips are better for high voltage/current applications.

Barrier strips are ideal for prototyping and connecting multiple wires in low power electronics and control systems. Terminal strips are preferred for connecting single wires in demanding electrical environments like junction boxes and control panels.

The choice between barrier strips and terminal strips depends on the specific needs of the application in terms of number of connections required, power levels, and safety demands. Understanding the key differences allows the installer to select the best solution for electrical wiring and connectivity.