Example of Electrical Insulator

Electrical insulators

The electrical insulators They are materials that prevent the passage of electricity through them. This feature is used to protect electrical circuits and connections.

Electricity is formed by those physical phenomena in which there are electrical charges that can be static, or flow through a medium.

Materials through which an electric current can circulate with greater or lesser difficulty are called conductors.

Materials that prevent the passage of electricity are called insulators or dielectrics.

Conductive materials are those that, in their electronic configuration, have electrons that can be easily detached, which makes electricity flow easily through that substance. Metals, some oxides, and electrolytes are conductors of electricity.

The Insulating materials are substances in which their electronic structures are stronger, and electrons are hardly detached from outer orbits, so offer high resistance to the passage of electric current, preventing in certain conditions that the electricity does not pass.

Some of these materials are air, glass, ceramics or plastics.

The main functions of insulators are the following:

Medium. Insulating material plates are used covered on one or both faces by a layer of conductive metal, generally copper. They serve as support for the electronic components and the circuits that are formed. These materials are combinations of fibers and plastics designed to withstand high temperatures and not burn.

Arc prevention. If the tracks formed with the conductive plate of a circuit support were exposed, there would be two drawbacks: Due to the proximity of some conductors to each other, small arcs could occur, which would cause a malfunction of the circuit. On the other hand, exposure to air and pollutants can cause oxidation of the conductive part, with the consequent deterioration and breakdown of the circuits. To avoid these inconveniences, once the circuit boards are made, the points where the components will be soldered are protected and They are given a bath of insulating varnish, which, in addition to being a poor conductor of electricity, is resistant to heat and combustion.

Insulation of conductors. Metallic wires and cables can conduct electricity from one point to another, and have the air between them as the only insulator. However, some circumstances can affect them and cause a short circuit, such as drafts that can cause them to collide with each other, or an excess of electrical voltage, which can cause arcs between they. That is why electrical conductors in the form of wires and cables are protected with an insulating layer around them. These layers are made of a PVC plastic, although before other flexible plastics were used, and even anti-flame fabrics.

Isolation of connections. When we join the ends of two conductors to give continuity or extend an electrical connection, we must protect the joint with some type of insulating tape. Nowadays, PVC adhesive tapes, plasticized fabric and thermoformable insulating tapes are used, which are placed on the connection and heated to fit the connection to be insulated.

Although insulators have the mission of preventing the conduction of electricity, when there is a flow excessive (high amperage), or a large potential difference (high voltage), the insulators reach the called dielectric breaking point, which is the point at which an insulating material can conduct electricity.

The insulating capacity and the dielectric breakdown point are different for each substance. For example, if we have two electrical conductors whose tips are 4mm apart, and we apply a small current, for example, 12 V, with a high intensity, such as 20 A, with only air being between both ends, having a low dielectric breakdown point, an arc will be formed with the passage of the current. If we place another material, such as wood, an arc will not form, until the intensity of the current reaches the dielectric breakdown point of the wood.

This is the reason why commercial electrical cables have a voltage and an amperage printed on them, which are the maximum working safety values ​​for that conductor.

Example of electrical insulators:

Thermoformable insulation: They are insulators in the form of a strip or tube, which is placed on the junction of the conductors, and heat is applied to them, fitting on the formed connection. Advantages: it fits over the connection to be insulated and saves space, increases the rigidity of the joint; it can also be cut lengthwise with a razor, to remove it, it leaves no residue. Disadvantages: It is much more expensive than electrical tapes.

Air. Advantages: makes it easy to make and control connections. Disadvantage: It has a low dielectric breakdown point, so arcs can be created.

Glass. Advantages: It is a good insulator and its transparency or translucency allows the connections to be seen. It resists very high temperatures. Disadvantage: In some cases it can be brittle when shocked.

Wood. Advantages: it is relatively inexpensive, you can insulate yourself as required. Disadvantages: It is flammable, so it does not withstand circuits with high loads.

Insulating tapes. Advantages: they are inexpensive, they can be made of cloth or PVC, they have an adhesive side, which allows it to adhere and wrap more easily around the conductors. In addition, they have resistance to temperature. Disadvantages: Over time the glue tends to deteriorate and peel off, while leaving the wire or cables sticky, which can affect the connection.

Lacquers. Advantages: Insulating lacquers are very useful to prevent corrosion and insulate circuit boards; they are also used to prevent the turns of motor windings from moving. Disadvantages: They are for specialized use for industry or repair, not for everyday use.

Ceramics. Advantages: Resists very high temperatures. It is a good insulator and its transparency or translucency allows you to see the connections. Disadvantage: In some cases it can be brittle when shocked.

Wax and paraffin. Advantage: It can fill blocks that require insulation and cover circuit boards. It is also used by impregnating paper that is tied or glued to the connection. Disadvantage: melts with temperature; if it is too high, it may ignite.