Terminal blocks are modular, insulated blocks that connect two or more wires together and, in their simplest form, consist of several individual terminals arranged in a long strip.
Terminals are useful for connecting wiring to a ground or in the case of electrical power for connecting electrical switches and outlets to the mains.
Terminal bodies typically consist of a copper alloy with the same expansion coefficient as the wire intended for use. This not only prevents loosening because of differing expansion rates but also reduces corrosion caused by electrolytic action between two different metals.
Terminal blocks are commonly mounted on some form of DIN rail. And our usual din rail types is NS 35.
Installing a new electrical panel
For The din rail terminal block strip using, for example if you decide to replace your circuit breaker panel you may find that the existing wires are too short to reach the new one. The solution is to set up an organized array of terminal blocks at the back of the panel enclosure and take the old wires to there, where they will almost certainly reach. Then run new wires from the panel to the terminal blocks. This makes for a very convenient and organized arrangement, you can attach the new wires to the panel before you install it. If you have more than one circuit to feed from each circuit breaker you just run a single wire from the panel to the terminal block, use a terminal jumper to combine two adjacent terminals, and then connect your two outgoing wires to the two terminals of the block.
If you want to get really fancy you can organize the wires on the terminal block in the same sequence they are on the panel, so if you ever lose the code that tells you which wire is which you will be able to figure it out by referring to the panel.