Electrical fuses are divided into two main types - fuses with a fusible wire and automatic fuses. They are designed to disconnect the power supply to the protected electrical circuit (circuit) in the event of a short circuit.
The fuses in the apartment electrical panel concern everyone. Therefore, we will focus on them in more detail.
The most powerful fuse (usually 63 A) protects and disconnects the power supply to the entire panel. After it, the electrical installation is divided into different circuits, supplying individual consumers. These circuits are protected by separate fuses, according to the installed power, but always with a lower tripping current than that of the main fuse, for example 25 A, 16 A, 10 A.
HOW IS CURRENT STRENGTH CALCULATED?
First of all, it is important to understand how power is related to the current that flows through the cables. Since the voltage in our network is 220 V, we can quickly calculate the current strength of each electrical appliance. If we take a 100 W light bulb as an example, we divide 100 : 220 and get 0.45 A. These calculations are necessary because when calculating an electrical installation, a power distribution is made, i.e. distribution of current in equal parts for each circuit.
WHAT PROTECTORS SHOULD WE PUT ON EACH OF THE CIRCUITS?
1. It is best to install a 63 A main fuse at the front, in series with the phase (almost always a red cable), so that we can turn off the current in the apartment from one place and provide backup protection. This means that our apartment can consume 63 A at 220 V = 13860 W, or in other words about 13 kW.
2. The least loaded circuit is the lighting, since a light bulb consumes from 5 W to 100 W. Then a 10 A or 16 A fuse will do the job for all the lighting in the apartment. Lighting in shops or offices (especially if there is a spotlight or more powerful illuminated advertisements) is a good idea to distribute to separate fuses.
3. Regarding the sockets in the living room, it matters whether we have central heating or electricity. You add up all the powers of a given circuit, divide them by 220 and get the required current in amps. Example: stove 3 kW + washing machine 3kW = 6 kW : 220 V = 27 A. It's good to be a little safe, so 35 A or 40 A will do the trick.
4. If we do not have powerful appliances in the circuit, we can install a 25 A fuse. For greater security, wet rooms - kitchen, bathroom, utility rooms - should be protected with a residual current device. When replacing fuses, do not install one with a higher tripping current if it trips too often. It is better to transfer the consumers to another circuit or divide the circuit into two with separate fuses.
HOW TO CHOOSE AN ELECTRICAL FUSE?
The main function of the electrical fuse is to protect the wires of the installation from overcurrents - overload and short circuit. For this reason, it is selected according to the cross-section and the method of laying the wire (in pipes, under plaster), according to the recommendations of the wire manufacturer. In all modern buildings, as a rule, automatic circuit breakers with the possibility of mounting on a DIN rail are used. These devices are very reliable, have a small size and fit well into the rooms and panels.
Protection of people from electric shock in electrical installations is provided by residual current devices. Circuit breakers cannot reliably protect against leakage currents, as they do not guarantee fast enough action at such low and safe for the installation, but deadly for humans, leakage currents.
CURRENT PROTECTION
When does the residual current protection operate?
The residual current protection operates, i.e. it switches off the supply voltage, when currents flow outside the phase and neutral conductors. A typical example is touching a phase with a hand. In this case, the current flows along the phase conductor - human body - earth circuit, i.e. outside the phase - neutral loop.
The current flowing in the phase conductor (L) is different from the current flowing in the neutral conductor (N), and the residual current protection switches off the supply voltage. For the residual current protection to function properly, the neutral conductor (N) and the protective conductor (PE) must be separate conductors, i.e. they must have a TN-S or TT system (three-wire version for single-phase and five-wire version for three-phase systems).
By regulation, it is mandatory for lines to be implemented as three- or five-wire with a conductor cross-section of less than 10 mm copper or 16 mm aluminum. After the residual current protection, the neutral and protective conductors must no longer be connected to each other anywhere.
Residual current protection is recommended for group protection against leakage currents of several outlets, with each outlet being protected with an individual circuit breaker against overload and short circuit.
It is used in both residential buildings and public buildings and in industry.
When does the fuse trip in the event of a short circuit?
For the fuse to operate in the event of a short circuit, you must:
- all consumers, sockets, lighting fixtures in the circuit must be grounded /or grounded/;
- not to protect an excessively long power cord (for example, a very long extension cord or several power strips connected in series);
- the installation must be effectively grounded (the resistance of the grounding stakes changes and must be measured every year).
WHAT DO WE OFFER?
We offer both types of electrical fuses - with a fusible wire and automatic. The variety of automatic circuit breakers is very large. We have models with one and three poles for all possible amperages /6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A/. You can also find residual current protection devices with us, which also have different amperages. You can also get stair circuit breakers, as well as contactors from our store.
