Electrical Terminal Blocks types
Okay…now that we have investigated some of the more common connection methods, let’s have a look at some of the different terminal block types.

1) Ground terminal block
At first glance, a Ground terminal block looks like a typical Screw-in terminal block.

Instead of connecting wires, the Ground terminal block connects the incoming wire to Ground.

The wire is terminated by the panel or the DIN Rail or wherever the block is mounted…We will talk more about DIN rails later.

Ground Terminal Block
2) Fuse terminal block
Fused Connection terminal blocks have a fuse inserted in series between the wire-in and the wire-out eliminating the need for external overcurrent protection.

To aid in troubleshooting, many vendors have included a built-in Fuse Failure LED circuit to provide a visual indication of the fuse condition.

Fuse Terminal Blocks
3) Thermocouple terminal block
A Thermocouple block is designed to accept thermocouple lead connections. Thermocouples cannot be connected to typical terminal blocks.

As soon as the thermocouple wire makes contact with the conducting material inside the terminal block an unwanted junction occurs.

Any dissimilar metals joined together will create a new junction, and consequently an unwanted voltage.

Thermocouples to Typical Terminal Blocks.
To avoid creating a new junction, some thermocouple connectors clamp the thermocouple leads together on both sides of the Terminal Blocks Connector.

Some vendors have developed Thermocouple blocks with the internal metal connection strip made of the same metal as the thermocouple wire itself.