- The principle of operation and the work of the RCD
- Motivation plants OUZO. Dangerous to the human body electrical current
- Selection RCD depending on leakage currents
- The causes of leakage current
- Types and RCDs; visual and technical designation
- Forums RCD
- tripping RCDs, causes of primary and secondary
- The main types of RCDs connection
- One security device and several circuit breakers
- The main types of wrong connection of the RCD, zero displacement of the protective conductor and
- Converter wool amps, online calculator
Primary protection of human body from dangerous voltages and current action in the domestic electric power networks and - setting the protective devices. Besides, RCD is used for protecting electrical appliances against emergency operation works in the household power mains and DC and AC sinusoidal current. But it works very often, and domestic consumers interested, Why is disabled RCD at the RCD or permanently activated.
The principle of operation and the work of the RCD
The sum of currents, which are included in the section, It must equal currents, that go. This is the main principle of this unit operates breaker. The reason for tripping RCDs in the power supply - it's, that the currents, that extend from a portion of electrical network, not equal currents, which are part of this network. This difference is the quantity of the leakage current or differential current. The vector sum of the currents in the phase conductors (I1) It must be equal to the currents in the neutral conductor (I2). They are identical in size, but the direction in different directions and thus cancel each other and emf (electromotive force) missing. If these currents are not equal, so, the difference between them and there is a leakage current. He, in turn, creates the EMF and it, in turn, through the solenoid acts on the shut-off mechanism and the RCD is turned off.
Motivation plants OUZO. Dangerous to the human body electrical current
On Fig.1 Normal mode is I1 = I2. When a person touches the bare wires, there is a differential current I∆n. If we calculate the current, which will pass through the human, you get I = 230/Rno, BUT, Where 230 The current from a household mains, Rno - human resistance. Although each person has this characteristic is individual, but it is considered to be about 1 k (1000 ohm). As a result, we get 230/1000 = 23 mA. It should be noted, that the threshold of sensitivity in humans begins with 0.6 – 1.5 mA. At this current palpable irritation in humans. When current in 10 – 15 mA in humans occurs muscle spasm, and this current is called neotpuskayuschego. In this case, a person can not independently release the bare wire, if he took him. at current 90 – 100 mA current arises fibrillyatsionnogo. With such a current cardiac muscle reduced chaotically, and after a few seconds going into cardiac arrest. Safe for humans is considered to be current 2 mA when it passes over 10 with, and if more 120 with, the safe current 6 mA. these currents, as well as time off must be kept in mind when selecting an RCD residual current, to understand, that will be with you, If you fall under hazardous voltage. For these reasons, remember, If the heater is turned off RCD, it saves you a minimum of discomfort.
Selection RCD depending on leakage currents
according to SP31-110-2003 p.A.4.15, if the bathroom is powered by a separate line, it is necessary to provide RCDs 10 mA, if the line is shared with a kitchen and a corridor, it is necessary to install the RCD current up 30 mA. For ordinary household power lines (sockets, lighting) the protective device is selected at a maximum current of 30 mA (PUE p.7.1.79.). RCD to differential currents 100 and 500 mA as seen above, do not protect the human body from dangerous voltage, and the main purpose of this fire protection. When installing the machine breakers need to understand, it does not protect against continuous overload, maximum currents or high voltages. For these reasons, this installation must be in conjunction with a circuit breaker with electromagnetic and thermal release device, and for overvoltage protection must be installed relays or surge arresters (Protection against surge voltages device). For these reasons, if TERMEKS disables RCD, and the machine does not work, then the cause of failure is leakage current.
If the RCD is turned off simultaneously with the circuit-breaker, the cause for the fault may be a differential current, and maximum currents, which arise when a short-circuit.
The causes of leakage current
You must have a good understanding, that the presence of leakage current - this emergency mode or a fault in the electrical networks of household purpose or malfunctions in electrical appliances. The causes of this current is quite common. The main causes of leakage current is a human touch to the bare wires, its flow through the deformed or insulation of the cable through the conductive element. For example, cause the RCD tripping in the water heater may be a leakage current through the water. The cable insulation corrupted, moisture penetrated the bare wire and the current through it went. current that is just not enough for, that would be a difference of incoming and outgoing currents equal 0 (zero) and protection disables the emergency section. If this water heater TERMEKS, RCD disconnected pribora.Voda this can also be the cause of,Why is disabled RCD at the pump pumping a variety of fluids.
Types and RCDs; visual and technical designation
- Household voltage and mains 220/380 AT.
- According to the number of poles. If a single-phase load in the power network, the RCD must be installed double pole, if the three-phase load, the four pole.
- The nominal operating current. The value of the nominal (working) RCD current for the same, as for circuit breakers, this 16, 25, 32, 40, 63, 80 BUT.
- Residual current (leakage current), by an amount which is guided device RCD 10, 30, 100, 300, 500 mA.
According to the type of leakage current, which in turn is divided into:
- Alternating electrical pulsating current sinusoidal and. RCD type for the current "AS ". Ripple current is present in regulated Lamps, washing machines in which the regulated speed.
- AC and DC electrical pulse, type OUZO "BUT". This type of protection devices is recommended to use it, where there is a consumer electronics, microwave, computer, TV, etc..
- Permanent electrical and AC, type OUZO "AT". This type of protection devices generally set, where there is a rectified current. The household electrical networks, this type is not used.
- For, selectivity that would be observed during installation of 2 or more protective devices in home networks and electrical power is applied to the RCD tripping time delay, This type of RCD «S». This type of RCD is used in networks, where ATS use (Automatic input of a reserve), and type "G», in the same network, but it has a smaller exposure time.
tripping RCDs, causes of primary and secondary
The most common causes of tripping RCDs in the boiler or water heater Electrolux, this unscrupulous manufacturer or various kinds of problems in the electrical network. If the RCD is turned off on the water heater, you need to turn it on again. If the appliance is working and does not switch off the RCD, then was short leakage current. Next, you need to use the button "Test". It simulates the emergency mode.
- You must disable automatic, are included in a network together with the RCD and identify, Why is disabled RCD. At the same time we disconnect the neutral conductor. After that, as they are disconnected, vklyuchaem OUZO. If it is not turned off, so, click on the button "Test". If after clicking "Test" RCD worked, hence it regularly. It should be noted, that the test RCD performance should be checked at least 1 once a month by pressing the "Test" button.
- If during connection RCD operates with no load, means it is out of order or in the place of its installation, there are leakage currents. If it is properly, it is necessary to understand, Why is triggered RCD with no load. In this case, If multiple machines from him, then all at once they disable. then we define, Why turn off the RCD, and in turn include circuit breakers and emergency section determine the electrical network.
The main types of RCDs connection
Connect the RCD can any electrician, having at least 3rd discharge electrician. Wiring diagram written on the device, and there is nothing difficult. The only thing that should be done prior to installation, is to take into account the nuances of when you turn on the network and select the right amount of off machines per RCD. You can set one security device on the whole apartment in the floor panel, if Condo, as shown in Fig.3. It can be installed separately on the network rosette and lighting, if you have enough space for installation. It would be suitable for an apartment. When installing and selecting RCD should take into account the nominal (working) current, to be one step higher than the rated machine current, which comes after the protective device. For example, if the machine on 25 BUT, before it is necessary to install the RCD operating current on 32 A etc. If it's a private house, it is better to consider the following items, one RCD and one automatic, If the machine is not much.
One security device and several circuit breakers
If a, for example, the house is worth a lot of machines (one machine = one room, = one or appliance), in this case the size of the electrical panel may be huge. For these reasons, better skomplektovat switchboard so, under one RCD to install multiple machines, but not more 5. In this case it is necessary to correctly calculate the rated current of the protective device relative to exhaust so automata, that their sum does not exceed the operating current protective devices. For example, exhaust machines BA1 16 BUT, BA2 16 BUT, VA3 32 BUT, the sum 16 + 16 + 32 = A. So the RCD should be rated current of at least 64 BUT, and knowing the optimal range of current ratings option device breaker rated current for 63 BUT.
As shown in Figure. 4 nothing complicated when there is no connection, but in some cases, it will be interesting to know, Why RCD operates on the water heater Ariston, if the home network and the safety devices are in good working order and. When triggered RCD, the reasons may be in its not properly connected.
The main types of wrong connection of the RCD, zero displacement of the protective conductor and
- It is impossible to connect the neutral (N) and phase conductor, passed through the RCD, other zero and phase conductors after RCD.
- You can not make the connection neutral conductor (N) after RCD electrical open design, as well as it can not be connected to the protective conductor (ON).
- Strongly not be connected to the neutral socket and protective conductor.
- If two protection devices are installed in the electrical network, the association of the neutral conductor will result in additional leakage current and consequently activation of both.
- If the electrical panel installed many RCD, you should double-check the wiring, that there was no connection of the phase conductor and the ground working with various protection devices.
Only properly selected protective devices and connected properly protect the person in case of an accident on the dangerous effects of electric current.