How to Choose the Right Terminal Block for Your Electrical Control Panel

Do you know that terminal blocks are the main components of an electrical system? Using a terminal block is a much easier and more efficient solution for connecting wires than taping them together or soldering them. However, these blocks come in a number of sizes, structures, and designs. So, how do you choose the right terminal block for your control panel?

In this guide, we are going to look at things that you need to consider when choosing a terminal block, so that it is the right fit for your control panel. 

30 Seconds Summary

• A terminal block is a modular, insulated housing that is designed to connect multiple wires securely. These are often used in industrial and electrical setups where it is important to have reliable and well-organized connections. 
• The common types of terminal blocks include: DIN rail terminal blocks, screw clamps, spring clamps, push-in, and stud/bolt terminals.
• Some of the most important factors to consider when choosing a terminal block are current rating, voltage rating, wire size, orientation and fit, block structure, wire securing method, compliance ratings, and quality. 

What is a Terminal block?

A terminal block is a modular, insulated housing that is designed to connect multiple wires securely. These are often used in industrial and electrical setups where it is important to have reliable and well-organized connections. 

How do terminal blocks work? These blocks often have clamps or screws for a secure and stable electrical connection. These clamps and screws also let you easily install, inspect, and maintain without damaging the wires. 

Types of Terminal Blocks

You can find different types of connection technologies in terminal blocks:

1. Screw Clamp Terminal Block

Screw clamp terminal blocks use screws to hold wires in place, and they can accommodate a wide range of wire sizes. 

2. Spring Clamp Terminal Block

Spring clamp terminal blocks, on the other hand, are a faster alternative to screw clamps. These use spring pressure to hold the wires in place and are often used for smaller wires. 

3. Push-In Terminal Blocks

Such terminals allow connections by simply inserting the wires. Most of the push-in terminals use a ferrule to strengthen the end of the wire. 

4. Stud/Bold Terminal Blocks

These terminal blocks are used in applications that experience extreme vibrations. The wires are crimped into a fork or ring lug and are screwed onto a flat current bar. 

5. DIN Rail Terminal Blocks

These terminal blocks are on standardized DIN rails, which is why they are the first choice for industrial control panels. DIN rail terminal blocks are modular, easy to install, and support a wide range of wire sizes. These blocks are often used for wire-to-wire connections and grounding in automation systems. 

Main Features of a Terminal Block That Need to Be Considered for Selection

When you are selecting a terminal block for your control panel, you need to consider various electrical parameters to make sure it is compatible. Here is what you should look out for:

• Current Ratings

Current rating is the maximum current your terminal block is able to handle without overheating. You should consider choosing a terminal block that is at least 1.5 times the maximum expected current in your system. This will prevent overheating and potential failures. 

• Voltage Ratings

Other than the current rating, you need to also consider the voltage rating. The maximum voltage a terminal block is able to handle depends on the material as well as the pitch of the block. You should choose a block that has a higher voltage rating as compared to your circuit, so as to prevent damages related to overheating. 

• Wire Size

You also need to make sure that the block you choose supports a wide range of wire sizes, i.e., from stranded to solid core wires. It is important to remember that many blocks out there are compatible with specific wire gauges. 

• Orientation and Fit

You can arrange the terminal blocks in different directions, like horizontal, vertical, or at a 45-degree angle. The way you position them should depend on the space you have and how easily you can reach them after installation.

For the DIN rail, which is a metal rail used to mount terminal blocks, make sure it fits properly in the space provided. There should also be enough room above and below for wires and other components. Don’t forget to consider the bend radius of the wires, as tight bends can cause problems. Accessories like jumpers, end covers, and brackets must also match the DIN rail’s size and specifications.

• Block Structure

Terminal blocks come in three main types based on their structure: single-level, dual-level, and triple-level.

1. Single-Level Terminal Block

This is the simplest type, and it is used for basic wire-to-wire connections.

2. Dual-Level Terminal Block

It has two connection levels stacked on top of each other. This design can handle more wires and increases current capacity without taking up extra space.

3. Triple-Level Terminal Block

These blocks have three stacked layers and are useful when you need multiple connections in a compact area.

• Wire-Securing Method

There are three common ways to secure wires in terminal blocks:

1. Screw-In Terminal Blocks

These use screws to hold wires tightly in place. They work well with stranded or multi-core wires and provide a strong connection. However, they take more time to install, and screws can loosen if the setup is exposed to constant vibration.

2. Push-Button Terminal Blocks

These are ideal for single-core wires. You press a button to open a spring clamp, which securely holds the wire in place. This method is faster and handles vibrations better than screw-in blocks.

3. Push-In Terminal Blocks

With these, you simply push the wire into the terminal, and a spring mechanism clamps it firmly. It’s quick, easy to use, and perfect for demanding industrial environments.

• Compliance Ratings

The way electrical enclosures have to follow NEMA standards, your electrical terminal blocks also have to meet safety ratings like UL or IEC. Such certifications highlight that the terminal blocks meet specific safety requirements. You should always choose blocks that comply with the safety standards of your system.

• Quality

Prioritize quality when choosing terminal blocks for your circuit. High-quality terminal blocks are reliable even in tough industrial conditions. They perform better, are even safe to use, and are also more likely to meet the safety standards. To be sure that your terminal block is of high quality, you should buy from trusted manufacturers or authorized dealers.

Over to You

Selecting the right terminal block is necessary not only for the safety, but also for the efficiency and reliability of your electrical control panel. 

For high-quality solutions, check out the wide range of terminal blocks from Go Switchgear to find the perfect fit for your needs.

FAQS

Q: What is a terminal block?

A: A terminal block is a modular, insulated housing that is designed to connect multiple wires securely. These are often used in industrial and electrical setups where it is important to have reliable and well-organized connections.

Q: How do terminal blocks work?

A: Terminal blocks often have clamps or screws for a secure and stable electrical connection. These clamps and screws also let you easily install, inspect, and maintain without damaging the wires.

Q: What are the types of terminal blocks?

A: Common types of terminal blocks include DIN rail terminal blocks, screw clamps, spring clamps, push-in, and stud/bolt terminals.