What is a Terminal Block?
A terminal block, also called terminal board or terminal strip, is a modular, insulated block which connects one or more circuits to another. The connections are usually made by a screw or clamp lowering onto a bare wire to complete the connection. They offer a convenient way of connecting individual electrical wires because they don't require a splice or physically joining the ends.
What does a Terminal Block do?
A terminal block creates an electrical connection when the wires are clamped down to the metal part of the block by a screw. They usually contain two long aluminum or copper strips that are designed to connect different components. These strips create a bus bar for power distribution that is sent to the connected components.
What do the number of poles mean?
The number of poles given in a terminal blocks description refers to how many circuits it is capable of connecting to.
Where should I use a Terminal Block?
Terminal blocks are commonly used in electricity wiring, to connect switches, and for connecting major appliances to plugs at home.
When should I use a Terminal Block?
There are a few devices that a terminal block is able to be used with including:
Ground Circuit Terminals – these are usually interchangeable with terminal blocks and can be plugged into a block when you need it. They are commonly used to ground components or systems.
Fuse Holders – this device is able to connect several fuses that are connected to multiple devices. So when there is a short circuit only the fuses connected to the holder will be affected.
Thermocouple Blocks – are able to measure the temperature by connecting thermocouples and giving a consistent metal connection
I/O Blocks – also known as an input/output device it makes it possible for there to be communication between a controller and device
Sensor/Actuator Blocks – this device can provide energy to three or four wire devices including: proximity sensors and photoelectric sensors
Power Distribution Blocks – are commonly used to connect power cables and provide an electrical current.
Disconnect Blocks – also known as a switch block this device makes it possible for you to easily remove a circuit with a knife switch and without removing wires.
How might I mount a Terminal Block?
Generally a terminal block is mounted on a printed circuit board (PCB) or there is a panel that is screwed into the wall that it’s able to snap onto. But here are some other mounting options for your consideration:
1. Rail- DIN (Deutsches Institut fur Normung) rails, in one form or another, are commonly used when you are mounting the terminal blocks. As you can tell from its name it is German and the rails design is their standard. The DIN does have several other sizes depending on your needs.
Miniature Top-Hat Rail – is around 15 millimeters or .05 feet wide and is able to handle terminal blocks up to 300 volts.
G32 Rail – the rail is 32 millimeters or .104 feet wide and is shaped like the letter ‘G.’ It is able to handle up to 600 volts from a terminal block.
Top-Hat Rail – has the same shape as its miniature brother but is going to be 35 millimeters wide or .11 feet. Along with its increase in size it is able to handle more voltage with 600 volts.
2. PCB Mounts, also called electronic blocks, are the other form of mounting. A terminal block will sometimes have been designed to PCB, pins may have been inputted so that they can be mounted through the circuit board, or you may just be able to plug it into a pin strip located on the circuit board.
How does a Terminal Block make a wire connection?
There are several different ways in which a terminal block can make a connection including:
Screw Clamps – this is the oldest and most standard way in which a connection is established. A screw is able to tighten the wire and make an electrical connection. This method is able to be used on a wide variety of wires and is the most reliable.
Spring Clamps – this method is a newer way to establish connections and are most useful when you are dealing with small wires and a small working space. It uses a spring to tighten the wire and to make a wire connection.
Insulation Displacement Connections (IDC) – makes it possible for a connection to be established without have to expose any bare wire. To make this connection the wire is pressed between two sharp pieces of metal.
Tab Connections – also known as spade or blade terminals, these connections are able to be pushed in and removed fast without needing to be soldered.