The steady demand for wooden residential buildings is equally typical for Russia and the United States. It is based on the environmental friendliness of such real estate, the good internal microclimate provided by it and other well-known advantages. It goes without saying that these houses have developed electrical wiring that allows you to enjoy all the benefits of modern civilization.
The main purpose of house power wiring is to deliver energy to various electrical appliances and devices, moreover, the total power consumed by them can be quite high and in some cases can be calculated kilowatts. Therefore, an emergency situation in the system is associated with the potential danger of uncontrolled release of large volumes of heat with subsequent fire.
The rules for constructing the wiring take into account the final probability of such an event and quite strictly and scrupulously normalize a certain list of measures to minimize their consequences.
The main design differences between American and domestic wiring
The main external difference of the hidden American wiring is the admissibility of the complete absence of targeted mechanical protection of current-carrying circuits.
This is expressed in the fact that:
- cables are laid directly in the thickness of structures without protective tubes;
- sockets are installed without metal sockets, Figure 1.
At the same time, taking into account a 2-fold decrease in voltage to transmit the same power, the current should be doubled, which is accompanied by additional heating of the wires. To compensate for this undesirable phenomenon, it is necessary to increase the cross-section of the core of the power cables.
The potential for overloading the outlet and the risk of fire is reduced by resorting to a mechanical interlock: 15 amp plug devices can be inserted into a 25-amp outlet, whereas a 25-amp plug simply does not fit into 15-amp receptacles. sockets. Achieving this property is greatly facilitated by the use of knife-like contacts at the forks, Figure 2.
The use of an uninsulated earthing conductor in 3-wire cables also increases the degree of fire protection, Figure 3. In this case, if the insulation of the working wires is damaged, the protection is triggered much more often.
Operational features of American wiring
American-style sockets are designed for the same current as domestic ones. This means that the wiring carries less power, which reduces the stress on it. At the same time, lower operating voltage reduces the likelihood of insulation breakdown and the risk of fire.
Additional protection against fire is provided by the following two features of the American rules for building house wiring:
- According to the first of these, power cables that are quite capable of withstanding 30-ampere current (AWG12 gauge, which corresponds to a section of 3.3 square millimeters), it is allowed to connect only through a 20-amp circuit breaker.
- The second rule limits the length of a 12-gauge cable to 30 m.If it is necessary to go beyond the specified limit, the rated operating current of the machine should be reduced to 15 A. The storage of 20-ampere circuit breakers in the network is only possible if cables with a smaller conductor gauge according to the AWG classification (or, equivalently, with a larger cross-section) are used.