How to connect aluminum wire to copper wire – overview of methods

What problems can arise when combining aluminum and copper

Not so long ago  electrical wiring in an apartment or a private house was made of aluminum wire, because it was enough to provide power to all the few existing electrical appliances. With the development of the world of electronics and household appliances, there has been a tendency to increase the load on electrical circuits. Hence, there was a need to connect the old and new wires.

When aluminum and copper come into contact, a chemical reaction occurs, which subsequently worsens the electrical contact, the contact point begins to heat up and may eventually become combustible and even fire. With increased ambient humidity, this process occurs very quickly, as a thin layer with high resistance forms between the conductors, which leads to heating and an open circuit. But still every electrician knows how to connect an aluminum wire to a copper wire, to avoid an unpleasant situation in the future.

The video below shows the effects of unsafe contact between copper and aluminum:

In any case, it is recommended to replace the old wires with copper, which will have a load capacity corresponding to the current consumption of electrical appliances. If it is not possible to completely replace the wiring with new ones, then partial wiring replacement. In this case, it becomes necessary to connect old and new electrical wires – copper and aluminum wires.

Different methods of connecting wires

There are several generally accepted basic devices that make it possible to eliminate direct contact between two materials that act strongly on each other. Let’s consider each of them separately.

Terminal blocks

Terminal blocks It can be equipped with a clamping or clamping mechanism. This design allows connection to one of the aluminum terminals, and to the other with copper conductive material, which are connected to each other through a steel plate. The plate is made of a neutral metal, which does not react with copper and aluminum – usually copper sheet or tinned copper sheet. For example, with the widely used Wago 2273 terminal, two to eight connectors of different cross sections can be connected simultaneously, mounted on a DIN rail using a special mounting adapter.

Clip-on pads are more reliable and are used in power rather than high voltage circuits. Most often it is performed using a nut”. This is a small junction box made of insulating material in the form of a nut, inside which is a block of metal plates through which the connection between aluminum and copper wires occurs. All of the above methods are associated with separable connections, that is, for multiple connections and disconnections, if it is necessary.

One example shows the complete installation of copper and aluminum in a junction box through the use of copper terminal blocks

Crimping method

Sometimes, when laying and installing electrical wires, it becomes necessary to make a high-quality connection from a single piece of copper and aluminum wire by crimping with sleeves. Very often it happens when inserting an electrical cabinet, electrical switchgear or when connecting a cable to an already installed unit, where it is impossible to replace aluminum with copper, and vice versa.

This type of connection of connectors is more expensive, because it requires a special tool. But at the same time, when performing various installation works of such a plan, professionals often choose it.

Wire crimping with sleeve provides a more reliable and durable connection. Using this method, copper and aluminum conductors are installed even for consumers of high power and high voltage in production. To carry out these works, you need a special tool and special copper and aluminum sleeves. It can even be pressed using a traditional hammer and metal plates, which is not entirely true, or there is a professional manual hydraulic press.

It is recommended to use such pressure not only when curling sleeves, but also tips. By the way, they can also be made of half copper and aluminum, to connect, for example, an aluminum cable to any device that has copper terminals or terminals.

Typically, aluminum and copper sleeves are used to connect large strands of cable conductors. With small clips, for example, in household wiring, several conductors are crimped into one sleeve. At the same time, the wires are brought in from different sides, to connect as if in a joint, as shown in the photo above. Do not stack the aluminum and copper conductors parallel to each other (lap), as shown in the illustration with a hydraulic press, because in this case there is a direct connection of aluminum and copper. Also, you cannot use copper sleeves with aluminum cable.

Rushed connection

Often, when working with electrical wiring, a simple person who is not involved in electrical work at home may have an urgent need to create a good and reliable connection between aluminum and copper wires. It is not recommended to run to the store to buy special tools and materials when performing one-time work, but it must be done with high quality.

Then it makes sense to use a regular screw with a nut and several washers. The main thing in this method is to split two metals that are aggressive towards each other using washers, as shown in the figure below.

Dead-end connection of aluminum and copper wires can be made in the junction box, which is an integral part of any connections in the house and in the apartment. Thus, even with various cross connectors they are easily and qualitatively connected through a bolt.

The loops of the wire should rotate in the direction of tightening the nut, with a deadbolt connection. This is necessary so that when the rings do not loosen and do not increase in diameter, but are wrapped tightly around the latch.

Another option is to use aluminum and copper tips and aluminum and copper washers. The aluminum cable lug can crimp and connect to the copper bus. Or, when using aluminum and copper washer, you can crimp the aluminum cable with traditional aluminum cable lug and connect it to the bus through this washer.

Live communication features on the street

When installing a cable line along the street, all communication elements are exposed to external negative factors, such as snow, ice, rain, etc. Therefore, to carry out such work, only a hermetically sealed structure, resistant to ultraviolet rays and low temperatures, is required. When making connections on a column, ceiling and in other open space, piercing clamps are often used. You may be interested to know in more detail how to connect SIP with a copper cable on the street, such as in this case, the connection of aluminum and copper occurs outdoors.

In rooms, when laying the cable in the wall under plaster, the cable is completely laid in the flashing, and any contact even with uniform metal is undesirable. All connections into the socket or junction box are carried out by any of the methods described above, which is suitable for each individual case.

Common mistakes, tips and tricks

I bring to your attention some useful tips that allow you to safely connect an aluminum wire and a copper wire to each other:

1. Before connecting the wires by welding, you need to know that tin copper it will be very simple, and aluminum only using special solder.
2. It is impossible to compress multi-core joints and single-core connectors too much. Otherwise, deformation and damage of the cores will occur.
3. It is always worth observing the markings and choosing the correct terminal blocks depending on the cross-section of the core and the type of installation (indoor or outdoor).
4. In no case do not use ordinary twists to connect aluminum and copper wires. This is one of the most unsafe ways to switch wires, which often results in a fire.

That’s all we wanted to tell you about how to connect copper and aluminum wires. We hope that the presented methods and rules helped you understand the essence of the work!