Guide to Terminal Blocks: Everything You Should Know About Them
Terminal blocks are the connectors that terminate a single wire & connect it to a circuit or other system. They come in various shapes, sizes, and ratings, but they always terminate a single wire (single pole) and are never multi-pole.
Though they are available as rows, still each terminal connects to only a single wire. Terminal block connectors are very useful in situations where there is a need for semi-permanent connections that might require inspections, wire replacement, repair & change. This is the reason why terminal blocks are incredibly common in domestic wiring & industrial environments.
The most common method of connecting terminal blocks is the use of a screw, wherein the wires are inserted & then clamped down with the help of a single screw. Larger terminal blocks that are used with large cables typically have a screw pushing the wire against a metal body, whereas terminal blocks that are used with thinner wire use a screw that pushes down on the lever or flat head; this compresses the wire against a metal insert. However, other terminal blocks can use screw-less levers, which can be considered as a fish trap. The wire is then inserted & the lever then comes down, preventing the wire from being pulled back out. Another terminal type is the terminal blocks with screws to hold an inserted cable on one end & a plug on the other so that the block can be inserted into the female connector (this enables hot-swapping).
Types of Terminal Blocks
- Screw terminals-These terminal blocks are the once that have a screw as the method for holding a cable or wire. Screw terminals are often found in situations where voltage & current demands will be moderate (domestic/commercial wiring).
- Barrier Terminals– These terminal blocks often have more than one termination point, which is used for multiple cables, and, because of this, they have small barriers between the individual terminals.
- Push-fit terminals– These terminals use small spring-loaded levers, which allow cables to enter the terminal block in one direction, but it doesn’t allow them to leave; thus, effectively holding the wire in place. This is the reason why they are called “push-fit.”
- Pluggable terminals– Pluggable terminals are the once that have a cable entry that allows the connection of a wire or cable and a plug output, which enables easy connection to a socket.
Advantages of Terminal Blocks
Saves time & Money
One of the biggest advantages of terminal blocks its cost. They are much cheaper than any other type of connector.
Terminal blocks also help in saving time as here the process of connecting wires is not as elaborate as some other connectors.
Investing in multi-level terminal blocks allow you to reduce panel space up to 50%. This is because the multi-level blocks contain multiple levels of circuits with that one single block.
Terminal blocks increase the safety by grounding, isolating & protecting the other components in the electrical circuit. They are available with finger-safe connections, which help in preventing electrical shock.
Also, they provide test points, which add even more safety to the circuit.
Terminal blocks can then be installed with a screwdriver. Also, they ensure fast connection/disconnection; this helps with both maintenance & troubleshooting. Additionally, with electrical power, the electrical terminal blocks can be used to connect electrical switches & outlets to the mains.
Made of Copper Alloy
Most terminal blocks consist of a copper alloy that uses the same expansion coefficient as that of the wire intended for use. Thus, using the same expansion coefficient helps to prevent loosening due to differing expansion rates. Also, it reduces corrosion, which is caused by the electrolytic action between two different metals.