Wire connection with nut clamps

The connection of conductors with the help of a "nut" is quite common. Cable clamp is so named because of the external resemblance. The term "nut" refers to the generally accepted and is used as an element of professional slang among specialists in electric power industry. The official name of the device is a branch clamp or clamp. In this article we will tell you what a nut is for connecting wires and how to use this connector.

Purpose and advantage of connectors

The main purpose of this clamp is to perform the necessary branches from the main electric wire without breaking the main line. A nut-type connector is installed at the junction of the trunk cable with branch wires without cutting it. To do this, it is enough to simply remove part of the external insulation and fix the clamp with the wire.

Electric peanuts photo

The advantage is that nuts allow connect copper and aluminum electrical wires. It is important to consider that the connection of copper with aluminum without the use of an intermediate plate, mainly brass, is unacceptable, since after some time the oxidation process can begin.

The connection of conductors using branch compression is most often used when it is necessary to install electrical networks for domestic or industrial use, or to connect lighting electrical equipment. The use of nuts for connecting wires is possible in all power supply networks with voltage up to 660 Volts.

Application example

Consider a multi-storey building consisting of seven floors. As you know, at the entrance to each floor it is customary to have distribution boards. From the lower floor to the upper, a four-core or five-core cable is carried out (in new homes with modern wiring, where the ground conductor goes separately). He goes through all the guards on the floors. From each shield is already powered apartments. In this situation, the use of a nut-type connector is absolutely essential in order to ensure that the electrical wires on each floor are connected to a common trunk cable without breaking it on each individual floor.

If in this situation, make a break "trunk" on all floors, connecting it to terminal blocks, this will significantly reduce the level of reliability of power supply to consumers. That is, in the absence of contact at one of the phases with consumers of lower floors, consumers of all upper floors, which, in turn, are connected to this phase, in this case run the risk of being left without voltage.

Squeeze design

The branch compression device is as follows: a metal core is located in a polycarbonate dielectric body (a material belonging to the group of thermoplastics, which is a polyester of carbonic acid and dihydric alcohols). This core includes two dies, as well as a plate between them. All parts are connected by tie bolts. In both dies there are grooves where the wires fit. Selection of a “nut” is made depending on the cross section of the trunk and branch cable / wire. The marking of the clamps can be as follows: U731M, U733M, U734M, U739M, U859M, U870M, U871M, U872M. The table below summarizes the existing types of connection clamps and sizes of conductors corresponding to each model:

Cable clamp marking

Wire Connection Rules

To connect the desired conductor to the main electric cable, you must first disassemble the clamp. To do this, it is necessary to remove the retaining rings located on the sides of the "nut". After that, the bolts connecting the dies and the plate between them are unscrewed.

Then required strip the cable according to the length of the intermediate plate inside the compress. Cleaning insulation is no longer advisable.

How to connect the wires further? Very simple! The exposed sections of the conductors are inserted into the grooves of the dies, and then tightened with screws. Now the resulting design is stacked back into the insulated polycarbonate "nut" case. You can see that there are four holes in the case. The first hole is tightly sealed, the second is intended for the branch cable, the main electric conductor is pulled through the remaining two holes. In this way, the electrical cables are connected with a nut.

Branch of a copper conductor from aluminum

Do not forget that the nut connection is not able to guarantee the tightness of all joints, therefore, during operation under different climatic and weather conditions, dust, dirt and moisture can get into the case. To provide some degree of protection, the compression housing must be insulated or, in other words, simply wrapped with electrical tape.

In the end, we recommend watching a video that clearly shows how to connect wires using a nut-type clamp:

Now you know what an electric nut is for connecting wires, what is its design and purpose. We hope the information provided was useful and interesting for you!

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