Without modern electrical appliancesthe comfort of our homes already inconceivable, but they can also become a source of danger for the property in case of fire and to our health and even life in cases of electric shock. Impartial statistics states that the cause of every third fire is fire in the wiring, which could be due to its overload, sparks a short-circuit, as well as damage to the insulation or poor-quality connection cables. To enhance the security of premises and people from electric shock and fire some time ouzo protective devices have been used: wiring diagram can cover their entire apartment or serve only a single line. If the connection ouzo is made in the first embodiment, in the case of an accident anywhere in the wiring from the power supply is turned off all the house, and in the second embodiment, the power is switched off only the failed appliance.
- The purpose of the installation and the problem of RCDs
- Types of circuit breakers
- Principle of operation, function
- Driving device connection
- Errors when connecting RCD
- the safe operation of electrical rules
The purpose of the installation and protective device problems
Before considering kinds of ouzo - a principleoperation and features of use, it should be understood that the tripping device is only an additional device, but does not cure under any emergency situations not related to current leakage.
Installing ouzo greatly increasesthe level of electrical safety, but does not exclude completely the risk of fire or electric shock if a short circuit occurs between the neutral and the phases for which it does not respond.
It does not work as ouzo device in the case,if a person will live, while touching a finger of the phase and neutral conductors. Between the flow of current through the wires under load and through the human body there is no difference, and therefore can not create a protection devices like touch. In this case, remain effective traditional protective measures: the device off before serving, non-conductive casings, insulation.
It is important to remember!
The device tripping ouzo - aAdditional protective measures are not replaceable fuse for protection against overcurrent. Ouzo only responds to a fault, not related to current leakage, for example, a short-circuit. Therefore, installation of ouzo must be carried out with the fuse - circuit breakers.
Types of circuit breakers
To prevent accidents inappliances, fire and electric shock to persons in power supply circuits of buildings for any purpose set special protective devices, which can be divided into types:
- AB - breakers;
- RCD - residual current device;
- DAV - Differential circuit breakers;
- RCD-D - protective devices with integrated protection against short-circuit currents or overcurrents.
Combined protective device RCD-D, ordiffavtomaty, with indication of quickly determining the cause of device operation - overcurrent or residual current. And the RCD, and the RCD-D perform the same protective functions listed below, but the RCD-D is more modern advanced instrument:
- Both devices increase the level of safety of electrical appliances and power tools.
- Both devices are equally prevent fires due to the ignition of insulation electrical conductive elements from residual differential current to the ground.
- D-RCD device, unlike RCD deactivatesseparate power station in case of overload (TK - overcurrent protection) or a short circuit, that is, an overcurrent (overcurrent protection - overcurrent).
Terms and electrical devicesregulate the characteristics of ouzo to be installed in the household power single-phase voltage of 220 volts, and the current is cut off should be no more than 30 mA, and the response time should not exceed 40 ms (milliseconds) - these values are indicated on the labeling of the device. Some manufacturers produce more sensitive and ouzo with a cut-off currents of 10-30 mA, for use in areas with high hazard and fire hazard. At the same time, there RCD devices having a cut-off currents of 100-300 mA or more for use on large areas, such as industrial premises and computer centers. Low sensitivity RCD perform only the task of fire protection, but they can not effectively protect people from electric shock. Low threshold sensitivity RCD devices in this case could lead to frequent false tripping.
When installing protective devices in residential areas should adhere to the following sensitivity marking devices:
- 10 mA - RCD, designed for very humid and wet areas (baths, saunas, swimming pools, showers and bathrooms).
- 30 mA - RCD for residential, utility and other spaces with normal air humidity.
It is important to remember!
In the group circuit to avoid falsealarms pose RCD 30 mA. To single users, a washing machine or stove, must be installed on a 10 mA RCD. On appliances installed in rooms with very high humidity, the installation of individual ouzo with a current cut-off of 10 mA is required!
Any RCD is designed for connection to the networka certain load limit and amperage indicated on the label of the device. When connecting the device tripping in conjunction with a fuse, you must select the ouzo with a higher amperage than the circuit breaker.
Principle of operation, function
Circuit Breakers AB, orfuses, fixed overcurrent occurrence in the network, which leads to overheating of a conductor or a short circuit. In the event of network congestion AB Turn the power off, thereby protecting against fire and decommissioning of appliances.
Devices tripping RCDs fix breakdownsinsulation of electrical equipment or wiring, comparing the electric current parameters for network entry and exit from it. If these settings do not match, there is a network disconnection from power and executed a person protective function against electric shock with possible contact with the uninsulated portion of the wiring and ignition prevention.
In accordance with the rules of the RCD is selected bysensitivity (10-30 mA) and the rated current, which is determined depending on the total capacity of all electrical appliances. Since the rated current is much lower than that of AB-breaker, short-circuit or over-current protection to protect the RCD can not.
Driving device connection
There is only one option how to connectouzo, when it comes to reliable stationary device: immediately after the counter, as it should protect all wiring in the house. When installing the RCD in the electrical supply house circuit, observe the following rules:
- the neutral wire must be connected to the terminal RCDs the symbol N, and the wires coming out are connected in accordance with the marking on the housing RCD;
- RCDs connected in series after opening the machine, the rated current is less than the corresponding current installation breakers;
- with two-wire power supply, which is notprovided the grounding conductor, the use RCD is vital, since it is not in need of grounding the design of the device will significantly increase the level of electrical safety of the house.
Properly connected residual current device - circuit:
Council: Traditionally, the leads connected to the instrument taken from the top, although it is usually not due to technical reasons. To improve security it is desirable for at least a switchboard, and preferably within the object as a whole, apply power to the same devices, either throughout the top or the bottom everywhere.
Of course, more economical way to connectprotective devices in the scheme is to install a device on the whole house. But in this case, if a leakage point in the RCD circuit disables all power to the building.
It is much more convenient, albeit expensive, is another way,where the Devices breakers mounted on separate lines:.. for the bedroom, kitchen, bathroom, nursery, etc. In such a scheme in the event of an accident on one of the lines of the house will not remain without electricity.
However, not in every case there is a possibilityinstalled on more than one switchboard RCD, and if the house wiring and it is too old, then the device can also create problems in the form of frequent false power outages.
If you do not want to, for whatever reason, orimpractical to install a stationary protective device can be fitted with an RCD socket or electrical appliances to equip the same plugs. Moreover, ouzo-socket can be mounted permanently on the site of the old stuck in a substantially similar adapter.
It should be noted, to save on ouzo ouzo-sockets and plugs-fail: their cost is almost three times higher than the price of conventional RCD, designed to connect to the switchboard.
Errors when connecting RCD
Often, when you connect the protective devicesoff on their own during the repair or construction of their homes, homeowners allow the same mistakes. The following scheme of incorrect connection of protective devices in the scheme will allow everyone to avoid annoying errors, thereby improving the security of your home power supply.
It is important to remember!
Do not install an RCD on the line appliances,feeding the installation of a fire or other disaster alarm. Surge or storm surge in private homes set in front of the RCD.
the safe operation of electrical rules
- Installation in rooms with high humidity switches and electrical connection without the RCD sensitivity of 10 mA is fraught with serious electrical shock or death.
- Do not connect on their own initiative the neutral wire from the RCD to an existing home ground: re-ground supply lines - Competence energy supplying organization.
- Improperly grounded neutral conductorcan cause accidents on the supply line: no contact, open circuit or burning-off of the neutral wire, overlapped wire on an overhead line, etc., can cause a fire...
- In the conduct of work on the wiring, especially in older homes, you must disconnect the power supply of the corresponding line or better disable shared apartment or house-breaker.
With a huge number of consumer electronics,appliances and computers in every modern house, on the electrical network falls very high load, and therefore the installation of devices tripping power in them is vital. How expensive would not cost the modern safety devices, it is not necessary for them to save, because the instrument costs, and especially the price of human life with these necessary expenses are incommensurable.