Wiring in a wooden house: rules, open and closed electrical wiring

Wooden houses have always been a symbol of coziness, warmth and spiritual comfort. Even now, when there are plenty of various modern building materials, many people prefer to build country houses and summer cottages from wood. And of course, any home in the modern world cannot do without electricity. But when planning and conducting wiring in a wooden house, you need to know and follow certain standards so as not to endanger property and even health.

General requirements

Electrical installation in a wooden house differs from similar work in houses built with less traditional materials. The electrical wiring in a wooden house must be carried out in compliance with special rules regarding the safety of the home.

From electrical wiring in buildings made of wood, it is required:

• Security. When laying wires, measures are taken to prevent the transmission of open flames to furniture and walls of the house. Cables must be protected from overheating and burning.
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• Design. Wires and wiring must comply with the peak load calculations for the power grid. The safety factor and technical characteristics must exceed the calculated ones by twenty to thirty percent.
• Correct choice of laying method. In order to constantly monitor the quality of the wires, it is best to lay them in an open way.
• Insulation. The electrical panel, which is the entry point for wires into the dwelling, must be separated from the wooden parts of the building with a fireproof dielectric.
• Good guide. Typically, a three-core copper cable with strong insulation is used. It is forbidden, according to all norms, to use PVC corrugated wires.
• Automation. Each separate unit of the electrical network must have a circuit breaker with an automatic fuse. The technical parameters of the circuit breaker must correspond to the load on the section of the circuit. The current rating is not greatly overestimated, so as not to cause overheating.

It is not necessary to carry out electrical installation in a wooden house without knowledge and experience - it is better to invite professionals. But the owner of the house must understand the basics of electrical engineering and the rules for using open wiring in a wooden house. This knowledge helps to monitor and diagnose already installed wiring.

Normative acts

There are a few basic documents to rely on when designing your home's electrical network. It may seem to a non-specialist that the information is presented too "dry", in an incomprehensible technical language. In this case, when reading on your own, it is advised to use the "Electrical Installation Rules". The publication describes in detail the basic concepts that should be relied on when conducting internal and external wiring in a wooden house.

Those who want to know all the intricacies of electrical work in a wooden dwelling should pay attention to the following:

• PUE, Seventh Edition. This is the main document governing electrical installation work. It normalizes the choice of wires, various devices and lighting.
• SNiP 3.05−06−85. In detail, using diagrams, lists the options for laying and connecting the main cable to the house.
• SNiP 31−02. Lists the requirements for wiring inside the home. Fully complies with the rules of the PUE.

Project preparation

Any work on the electrification of the building is preceded by the creation of an individual project. For its approval and agreement, an application is drawn up at the nearest branch of Regional Electric Networks OJSC.

After the approval of the document, an agreement and technical conditions are drawn up to officially connect to the local power grid. After that, detailed documentation with wiring diagrams for the project is developed. Design includes:

• Calculation of the total power. The sum of all the capacities of household appliances in the house is calculated with a margin of thirty percent.
• Drafting the project. A detailed plan is drawn showing the location of outlets, lamps, and so on. The plan indicates the number of elements of each of the groups connected to the network.
• Choice of cable diameter. Selection of wire cross-section based on the technical characteristics of each group in the network.
• Location and number of junction boxes. If there are many apartments in the house, then you should select and indicate the place for the junction boxes.
• Cable routing. The project should provide for the only correct and reasonable way of laying electrical wiring. Be sure to note the distance from the floor, to the ceiling, windows, etc. at all sites.

According to the rules of PUE, cables are located only horizontally or vertically. If you need to bend the wiring, then the recommended rotation angle is ninety degrees.

Sockets and switches are located in accessible areas with free space around them and convenient access. The number of outlet groups may vary depending on the type of room, its size and the needs of residents, but the documentation recommends placing at least one outlet for six square meters.

Installation of electrical wiring

For installation, a number of tools are required: an electric drill, a screwdriver, a set of screwdrivers along with an indicator, a measuring meter, pliers and nippers.

The whole process can be broken down into a number of stages: laying wires from an external electrical network to the house, assembling distribution board, laying of external and internal wiring, installation of socket groups, checking performance.

Distribution boards

A switchboard is a structure for entering an external cable into a house and distributing current in directions. The shield is a box in which the nodes are placed that correct the operation of the network, keep records and are responsible for security.

The dimensions of the shield depend on the number of nodes and for wooden houses, the capacity is usually calculated for twelve to fifteen elements.

Install the shield vertically at a height of about one and a half meters from the floor on an insulating material. Often a small utility room is designed in a wooden house in which the device is installed.

When installing in the distributor, the front panel is removed and through the holes on the rear panel, markings are made on the wall. Then holes are drilled in the wall for dowels and the shield is attached to them with self-tapping screws. RCDs, meters, fuses are located inside the shield. The nodes are placed in the order of decreasing current strength.

Connecting to the network

There are two ways to run wires into a room: through the air or underground. Usually, the underground method is preferred, since in this case an armored wire with additional protection from corrugated foil is used. The depth of the cable should be thirty to forty centimeters.

The cable is carried through the air when there is a very large distance between the substation and the dwelling. In this case, the cable is connected to the supporting cable and the entire structure is pulled between the support point and the house. If the cable length exceeds twenty meters, then an additional support has to be installed.

Open wire placement

This is the most rational and popular way of wiring. It has been used for a long time and before its use could be easily seen due to the white ceramic insulators - "cups".

With this method, the wire does not come into contact with the wood wall.

Currently, this option is used only if the power of all devices does not exceed four kilowatts. In those rooms where the load is higher, this method is abandoned.

With open wiring, the following mounting and protection options are possible:

1. An electrical conductor with a diameter of up to six millimeters is attached with heat-resistant plastic clips on the wall surface. Copper core wire with double or triple braid is the best choice. If the cable has conventional insulation, then it is additionally protected by a fireproof gasket. It runs along the entire cable and protrudes from both sides by eight to ten millimeters.
2. The electrical cable is hidden in polymer channels. You can choose different channels for design solutions and with different technical characteristics. The cable channel is mounted on self-tapping screws, and the wiring itself is protected by a front cover. For inspection or repair work, the faceplate is removable.
3. The wiring is laid in a metal corrugation with a cross section of up to two centimeters. A positive feature is the ability to place a whole bundle of cables in such a corrugated pipe. In addition, the metal reliably protects against serious damage. During installation, the pipe is fastened with fire clips, and a gap of one centimeter is formed between the wall and the wiring.
4. Sometimes polymer pipes are used instead of metal pipes. The polymer pipe is attached in the same way as a metal corrugation and provides excellent protection against heat or fire. The disadvantage is that in case of repair or the need to access the cable, you have to disassemble the entire problematic unit.

Sometimes a combination of straight metal pipes is used, which are located on straight lines and corrugations that form turns. This is a very reliable method, but does not always fit into the design of rooms.

If metal parts are used as wire protection, then all of them must be grounded.

Concealed cable routing

This method of laying is rarely used because it requires more work than with open wire wiring. But those owners who believe that an open wire is inappropriate use hidden placement technology. In this case, some requirements must be observed:

• The cable sheath must be non-flammable. Such protection can be a metal corrugation or a steel tube. The inside must be galvanized. Without protection, the cable cannot be used categorically.
• On a horizontal section, the cable is laid at a slope, so that moisture can drain downward. For better moisture resistance, where water accumulates, holes are drilled in the protective casing. Swivel parts are made from threaded parts. They are welded or soldered to straight sections.
• All switches, switches and socket groups must have metal bases and are grounded. The place of attachment of protective pipes and rosettes is treated with sealant.

Installation errors

Unfortunately, traumatic incidents and fires in wooden houses occur due to gross errors and violations during the installation and operation of the electrical network.

Major mistakes:

• With hidden cables under the ceiling, the wiring is without protective insulation. Small diameter wires can overheat and ignite dry wood surfaces.
• If the cable lies under the skirting board, then due to the limited space and tight contact of the wires with easily flammable parts, spontaneous combustion is possible. If the cable is laid under the floor, then the wire must be hidden in a box with a space of ten to fifteen millimeters.
• The use of different PVC pipes can lead to melting of the protective surface and direct contact of the overheated core with the wood.

Boxes for sockets must be made of metal, since plastic does not protect against overheating.

System test

At the final stage of the electrification of the house, to check all the networks, electrical measuring devices are needed.

When checking the performance, the following are carried out:

• External examination of the electrical network, contacts and insulation.
• Measurement of the value of insulation resistance.
• Resistance measurement on the ground loop.
• Evaluation of the operation of the zero-phase circuit.
• Testing fuses.

After successful testing, a specialist from the governing body confirms the completion of the work.

This means that the wires are laid correctly and can be used safely, observing the rules for operating the network.

Electrical work in a wooden house is a very complex and important process that requires accuracy, care and knowledge. A craftsman who decides to lay electrical wiring with his own hands should think carefully in order to prevent technological errors that can lead to traumatic consequences.