Table of Contents
Without connection of the country house to electricity it is impossible to provide comfortable stay. And, naturally, each owner waits for the moment when it is possible to use the electric power, with impatience. Electricity brings to the house heat and light, opportunity to use huge number of the devices which are facilitating life, bringing joy and brightening up leisure.
But the majority of dachas is under construction of wood, that is, by definition of firefighters, of “combustible materials”. According to statistical data, big half of the fires happens because of these or those malfunctions of electrical wiring.
How to make electrical wiring so that everything that has been built, at once has not turned into pile of brands or, what is even more terrible, the faulty device has not deprived of someone life? It seems that it is not so difficult: it is enough to get acquainted with the corresponding literature and to have at least small skills. But it would be simply if there were normative documents which are well stating the instruction with the sequence of actions. However such instruction does not exist. Or rather, necessary information is scattered by different rules of the device of electrical wiring. Except that this information is separated, it also “is ciphered” by technical terms, most often to unavailable people without profile education. As a result wiring in wooden houses is most often mounted also, as well as in apartments of multi-storey buildings and it is very not right as structures of such buildings are made of the materials resistant to fire.
Therefore we will consider question of single-phase wiring most of which of all and is widespread in country houses. In this question there are many nuances which can study only thanks to practice. But, at least, thanks to material it is possible to receive the general concepts how to install electrical equipment to the house, to understand as far as already existing wiring conforms to requirements, and to check work of the contractors performing electric installation work.
Input of electricity in wooden house
First of all, it is necessary to bring the electric power to the house. As a rule, the branch is made from overhead power transmission lines. Modern requirements discuss that the branch is made through insulated wires with section from 16 square millimeters. The self-supported insulated wire the Self-supported insulated wire 4 dressed in cover from light of the stabilized polyethylene best of all will be suitable for this purpose. Such type of isolation is steady against ultra-violet radiation, and the term of its service exceeds 25 years.
Connection of wire to the VL and its transition to other cable at input to the house is carried out by means of special armature. Wedge (anchor) clips are hermetic, do not allow to get to moisture under isolation, provide high-quality contact and are calculated on certain loading. If loading is exceeded (because of falling of trees, snow failure, etc.), clips collapse. The cable at the same time remains undamaged, there is no violation of power supply and there is no danger of electric traumas because of accidental contact of broken wires. According to PUE the distance between the earth and wire on input should not be less than 2.75 m of meters.
The technology typical for application of former times is sometimes applied: the wire on input is allowed into the house through the most normal rubber hose, instead of use of ceramic insulators through passage. But rubber becomes brittle under influence of ultra-violet radiation and bursts from mechanical loading. As a result metal opens. Besides because of time, kind of it was not strange, rubber loses the insulating properties and becomes the conductor. It can be shown during wet weather, and later, because of heating of hose, it can quite lead to ignition and the beginning of the fire. Therefore at the device of new input it is impossible to use such method at all, old input in which the rubber hose is used needs to be replaced without fail.
Input directly to the house by means of self-supported insulated wire cannot be made, according to the existing rules cables with aluminum vein it cannot be carried out on combustible designs, it needs to be replaced with wires with copper vein. The most preferable option — VVGNG. Such cable intends for stationary wiring as indoors, and on air. It is in addition desirable to place cable in corrugated plastic pipe. Before installation of corrugation of pipe it is necessary to be convinced that it has certificate of fire safety. In places of passing of cable through overlappings and walls metal plugs from steel thick wall pipe are installed. Wall thickness of pipes decides in 2.8 millimeters for cables on section 4 square millimeter and 3.2 millimeters for cables at 6-10 of square millimeters. The pipe is necessary for protection of cable against the mechanical damages happening at shrinkage of the house and from mice who can quite gnaw through wires. But, first of all, pipes are for a while capable to localize fire which has arisen at ignition of cable and not to allow it to extend to wood structures.
The most dangerous site – passing between external wall of the house to distribution guard. Usually it has no automatic protection and passes in contact with combustible designs. It is possible not to expect the protection established at the transformer station as it is guided by big currents, and can not feel short circuit. Therefore surely it is necessary to take additional security measures.
The next ways of protection can be used:
- Already mentioned way — steel thick wall pipe in which the cable cleans up throughout to guard from the place of contact with house wall surface. This option is suitable for not too long (up to 3 meters) distances to guard and in cases if on the way of cable the minimum quantity of turns to stretch it through bends too difficult.
- The additional protection established on input. On external wall the bipolar circuit breaker in dust and water tight boxing is put. The face value of the automatic machine has to be higher input in panel board on one step than the house. If there is overload in network, then the first protection in panel board will work and it is not necessary to climb constantly to the place of input ladder. One more option – selection of protection for operation speed. Then in panel board will be input with characteristic “In”, in boxing – “With”. And the face value of the automatic machine has to be selected on cable section. For example, in panel board — 32A, in boxing – 40A. In that case it is possible to connect electric devices whose total power will reach 7 kW, and it more than is enough.
This way will allow to stretch cable on more convenient way, to establish guard at any distance from input and to get rid of bulky pipe. But also in this case passes through overlappings and walls are mounted in steel shell.
- The kind of the last way — protection is established on electricity transmission column. Act in the reconstructed and again connected settlements usually this way. Along with the circuit breaker also the counter is put. This option is convenient for the power supplying organizations whose inspectors can take readings without entering the room. Besides the limiting circuit breaker forces users to spend energy no more than the emitted power.
The convenience of way is that all site of branch is protected. However protection operation most often cannot be turned off independently and it is necessary to address services of the servicing electrician that inconveniently and, in addition, not free of charge.
It is possible to tell that the majority of the conclusions which are carried out earlier works also without similar tricks, but you should not forget also that then nobody could expect modern requirements and loadings.
Introduction distributing device
The wire entered into the house is connected to the guard consisting of the introduction bipolar circuit breaker, the counter, automatic machines of protective shutdown and the device of protective shutdown. Its assembly will require DIN rail on which installations are mounted, grounding (if the contour of protective grounding is made) and zero tires, connecting wires with corresponding to loading section, sealing boxing for automatic protection, the connecting tire and cambric for double isolation of wires.
The quantity of circuit breaker has to be picked up depending on that how many groups of consumers they will service. So in the standard apartment of these submachine guns two: the first for protection of the network line, the second – socket. For country house load dispatch on rooms is more logical. In this case the cable is saved and it is simpler to find malfunctions.
For example, in the house several zones are planned: bedrooms of the first floor, penthouse, kitchen and terrace.
The most power armed zone – kitchen. Means, it has to be protected by the most powerful automatic machine – 16A. Bedrooms and penthouses — 10A, but if heating devices are used, then and here it is 16A circuit breaker better to put. More powerful automatic protection it is impossible as they get out that to the weakest link in chain. The thick cable can pass and 25A, but the standard socket is calculated N currents no more than 16A. As a result than the smaller face value of protection, owners can be that more quietly.
What requires the device of protective shutdown? This device reacts to leakage of current and protects from defeat by electricity. It is considered that the device of protective shutdown is inefficient if there is no protective grounding, but it is incorrect. It works and in that case, but only when someone touches the faulty device, thereby saving someone’s life. In country conditions it is desirable to put the device of protective shutdown on the line of street sockets, on the line of bath. It places in which the contact with water is assumed, that is. the danger of defeat is increased by current.
The device of protective shutdown – not the cheap device therefore it is quite clear to save desire. The small economy can be limited to installation of protective shutdown only on lines about which it was mentioned above or to put the general device of protective shutdown for all wiring. But the last option will complicate search of possible malfunctions and, at branched, long wiring will lead to the probability of false drops.
When choosing the device of protective shutdown it is worth paying attention to two important characteristics: maximum current and leakage current. The last parameter usually, except for dangerous places, is chosen equal 30 mA. And the maximum current is selected above the current the circuit breaker standing on this line on step. For example, if the circuit breaker — 10A, means the device of protective shutdown – 16A and if the circuit breaker — 16A, then the device of protective shutdown – 25 or 20A. At installation the device of protective shutdown to all line, its face value is guided by input the circuit breaker. So, at introduction automatic protection in 32A, the device of protective shutdown is calculated on current in 40A.
There are differential circuit breakers. These are rather expensive devices which installation is not always justified. Often for them there is just not enough place in guard. In particular and because of it it is not necessary to save on the guard sizes. It is better to pick up it with possibility of further increase in contents as, it is quite possible that over time in the house new lines will appear. And, naturally, automatic equipment filling guard has to be from the checked producers – you should not save on safety of housing and own life.
Most often in wooden houses open wiring is mounted. Of course, it is possible to equip and hidden, but if to carry out it according to standards of safety, it will be required to spend many means, and it is not always justified. But we will consider all possible options.
- Open, including unprotected cable
For stationary wiring single-wire rigid cables in isolation are used (double or threefold). Material of isolation should not sustain combustion. NYM treat such cables. If laying is made by single cable with vein section no more than 6 sq. mm, fastening is allowed to be made by means of electromechanical brackets.
If the cable with normal isolation is used, then under it it is necessary to establish laying from any non-combustible material (asbestos or metal) so that from each party from wire 10 millimeters of laying acted. One more option – ten millimetric air gap between cable and the combustible basis. This way is similar to how earlier the electrical wiring was carried out by twisted wires on ceramic rollers. But now neither similar rollers, nor twisted cable can almost be got.
It is the cheapest way, but its essential shortcoming – not too esthetic exterior, especially in places with several parallel cables.
- Electrotechnical corrugated pipe
In many respects campaign on the above described way. The cable drags on in flexible plastic corrugated pipe. The pipe has to have certificate, confirmatory that material does not extend burning. Pipes by means of special clips fasten. The convenience is that at the same time in one pipe there can be set of cables at once. Such wiring looks is accurater than open cable, but rooms begin to remind certain industrial premises. Besides in need of banner it is necessary to replace and remove the whole pieces. But such way safer as provides additional protection against mechanical damages and some air gap between combustible surfaces.
Similar wiring can be executed also in plastic rigid pipes, but it is not so convenient.
- Cable channels and electrotechnical box
The cable keeps within the plastic body (cable channel) and are closed on the latched cover. Material cable channel – the plastic which is not extending burning.
Accurate installation of boxes will demand the good tool and certain skills. They look much more esthetically than the last ways, but straight lines of boxes can emphasize curvature of ceilings and walls. Therefore when mounting it is necessary to think over arrangement of boxes in advance so that they did not spoil, and, perhaps, and decorated the room.
Very important advantage is that box allow to make changes, to change configuration, to establish additional branches, to mount new switches and sockets. The sizes of boxes can be different, also additional elements are issued: stubs, branches, joints, internal and outside corners. Besides it is possible to select them for color.
But also there are shortcomings. For example, when mounting on badly dried out wood joints after drying of tree extend, and box are bent. Therefore their installation has to be carried out after drying of tree. Such way is more expensive, but the set of qualities does it more preferable.
Such wiring can be made only in pipes of metal. The majority of sources does not recommend to carry out the buried wiring on combustible designs. However it can quite be made with observance of safety rules. And, if there is desire and means (it is more expensive than opened), then it is quite real allow.
The main requirement – cables have to consist in the cover localizing burning – the steel pipe painted or zinced from within for prevention of emergence of rust. It will not allow to extend to the arisen fire to enclosing structures. Turns of pipe are carried out by means of welding or on thread. Exits are made out protecting cable from contact with sharp edges, plastic inserts. Pipes have to keep within with small inclination which will provide outflow of the appearing condensate. Terminal boxes, sockets, switches are mounted in metal adjusting boxes. After broach of cable and mounting of pipe it is closed by finishing material.
One more method of the hidden laying — on plaster coat. Its thickness around cable has to be not less than 10 millimeters from any party. This method reminds the buried wiring in stone houses. But in that case the requirements of concerning removability of wiring are not fulfilled. It is possible to lay wires in corrugation, and then to cover design with plaster. But it will be only formal implementation of recommendations, in fact to draw such wire it will not turn out.
Concealment of wiring behind plaster seems by simple method, but in fact it brings many troubles. How will plaster through time keep whether cracks will appear? The answer to this question cannot be given at once.
Sometimes councils for the buried wiring put in the rigid plastic pipes or the same to corrugation closed in effect by covering meet. It is impossible to do so categorically. The assemblers who are carrying out the buried wiring thus are tempted with simplicity of work, but set up “mine of the slowed-down action”.
What it is worth paying attention to?
Notorious contacts, position of joints of wires become the weakest link of any electrical wiring. The screw joint, welding, soldering, spring terminal blocks or connection is allowed by special clips. And here most often the found twists are strictly forbidden. High-quality soldering or welding is available only to the professional. And if to consider that work can be conducted in limited space or under ceiling, then and in this case it is impossible to guarantee quality. Besides welding demands the special equipment. Screw joints need to be checked periodically. Therefore wide circulation was found by spring terminal blocks. They do not demand considerable additional expenses, provide high quality of contact and do not demand the subsequent service. And the convenience of mounting reduces mistake probability during performance of work.