Do you know how the leakage of electric current happens? Electrical leakage is a mystery to many electricians and there are several important details about current leakage and know that certain increases in the electricity bill can be a classic case of electrical leakage. Knowing this in this article we will show what causes current leakage and what are its consequences.
What is electrical current leakage?
The electrical current is commanded movement of electrons by a particular conductive material and its power unit of measurement is given in amperes (A), one of the main electrical quantities.
The leakage of electric current is characterized by an electric current that, in addition to flowing into the main circuit, is drained into another mass during its course.
The leakage of electric current can happen in two ways, where the first is when the leakage of electric current happens in the cables of the electrical installation. However, the second way that electrical current can leak is when this current leak occurs in appliances or machines.
To facilitate the understanding of what electrical current leakage is, we decided to draw a circuit with a load connected to the outlet, the load can be a lamp, a washing machine, a refrigerator, in short, any device or equipment connected to the electricity. The current circulates naturally between phase and neutral or phase and phase, this is the operating principle of an alternating source electrical circuit for example.
And when, due to some situation in the circuit, part of the electrical current “escapes” from the circuit to ground, we have leakage of electrical current. In our drawing, part of the electrical current, which is the yellow arrows, is going to ground.
How to happen current leakage.
What is electrical leakage?
It is important to understand that a cable with the exposed conductive part is not necessarily a current leak, so that there is a current leak it is necessary that this conductive part of the cable is touching a grounded point.
One of the main problems with the leakage of electric current is that this energy circulating “out” of the circuit will not generate an effective job, because electric current will be dissipated to the grounding system, causing a considerable increase in the electric energy consumption of the residence.
The most serious current leakage situation is when someone touches this energized point and receives an electric shock . The electric shock is leakage of electric current, because part of the current that should return to the system goes out through the person’s body and goes to a grounded point, for this reason it is important to always have a good grounding system in the electrical installation.
Electric shock can kill.
The current leak is electric shock.
Leakage of electrical current in installations
The leakage of electrical current in the installations is the leak that most occurs. It is very common to hear someone saying that from one month to the next there was a very large increase in the electric bill, this type of report is a strong indicator that in that installation there is a current leak.
The 5 conditions for current leakage
The first condition: in poorly insulated seams , poor insulation causes the insulation resistance to provide current leakage, if this seam touches any conductive and grounded part of the installation, as is the case with metal passageways.
The amendments must always be well isolated.
Leakage of electrical current in badly isolated seams.
The second condition: cable with dry and brittle insulation, cables that overheat and constantly cool above the limit for which they were manufactured, end with the dry and brittle insulation layer.
Dry cables can cause fire.
Leakage of electrical current in cable with dry and brittle insulation.
The third condition: damaged cables, the cables can be damaged when the cable routing during the electrical installation is not taken care of, thus injuring the cable. This injury is when some part of the insulation is damaged leaving the copper part exposed. Another situation that can occur is when a rodent like a mouse bites the cables and damages its insulation layer.
Always check the cables before completing the installation.
Leakage of electrical current in wounded cable.
The fourth condition: humidity and infiltration, in a passage box on the floor, water infiltration is common, especially in places where the floor is constantly washed, but this can also happen in installations on the ceiling and walls. Moisture and water greatly decrease the electrical resistance, so in this case any badly insulated splice, dry cable and injured cable will provide an electrical current leak.
Water will seriously damage the electrical installation.
Leakage of electrical current due to moisture and infiltration.
The fifth condition: sloppy apparent cable installation, cables fixed in apparent installation such as under roof or over ceiling lining are exposed without mechanical protection.
Many of these installations are fixed with nails, screws and other fasteners that if misplaced can pierce the cable insulation. And since they are directly attached to the masonry of the installation, we are in a perfect condition to provide leakage current. This type of cable installation exposed to the NBR 5410 standard requires the use of cable with double insulation , so the cable is protected from mechanical shock.
Apparent cables must have double insulation NBR 5410.
Leakage of electrical current in the apparent poorly installed cable installation.
Current leakage in appliances and machines
Another situation that can cause electrical current leakage is when an internal cable of an appliance or machine, or even some component fails and energizes the appliance’s housing. The leakage of current in these cases will only occur effectively when someone touches the device is electrocuted, or if these devices have a grounded housing.
There are double insulated appliances and appliances, which is when the circuits are protected from the appliance housing, precisely to prevent the appliance housing from being energized in the event of failures. But many appliances like refrigerators, electric ovens, microwave ovens do not have double insulation.
There are devices with double insulation for safety.
Leakage of electrical current in electrical appliances and machines.
The devices that do not have double insulation the third pin on the plug of the socket which is the grounding pin. The third pin must be connected to the grounding of the electrical installation in order to drain the electrical charge accumulated in the housings in the event of failure, so the third pin should never be cut, but the socket must be replaced.
We must never cut the third pin of the plugs.
The third pin must be connected to the ground of the electrical installation.
Residual differential DR device
The best way to prevent accidents and wasted energy due to the leakage of electrical current is using a DR , as the DR is the only safety component that identifies and protects against current leakage.
The DR switches off the electrical circuit in the event of a current leak, ensuring protection against electric shock. When an electric shock occurs, the DR shuts down the entire circuit in the quickest possible time and this is essential to prevent the person from being trapped by being electrocuted, so it is always important to have a DR in your electrical installation.
Avoid serious consequences of electric shock.
Residual differential device.
The increase in energy consumption is the least of the problems of the leakage of electric current, since the person can take an electric shock that in many cases is fatal, so it is of great importance to have a DR in the QDC . Below we leave a video of the Mundo da Elétrica channel, with a complete lesson on DR, IDR and DDR.