Electrical wiring

Electrical installation is the installation of electrical systems for low voltage. In the strict sense is understood as including the power supply described below and the electrical lighting installations for buildings; similar methods and materials are however also used in industrial equipment and control systems and on vehicles.

Scope

The electrical installation includes the wiring and installation of distribution boards, overcurrent protection devices, residual current circuit breakers, miniature circuit breakers, lighting, electrical appliances, electrical machines, sensors such as motion detectors, twilight switches, switches, buttons and sockets as well as the final measurement of the effectiveness of protective measures.

Task of the electrician is to make the individual components to be connected so that the circuit meets the required function and there is no danger of electric shock. When work is to avoid electrical accidents, the relevant safety rules, in particular the five safety rules must be observed.

The minimum number of sockets and circuits per room and apartment is set in DIN 18015 and RAL RG 678.

Embodiments

In principle there are two ways to plan and build electrical installations:

• Centrally
• Decentralized

Advantage of centralized electrical installation is that all important resources are combined in a manifold, enabling rapid troubleshooting. The disadvantage here is that the most long cable lengths must be accurately dimensioned to consumers to keep voltage drops as small as possible. In the decentralized electrical installation the resources are located close to consumers, which means a better investment clarity and significantly less cables and wires. An advantage of this is in addition to the lower cost and the significantly improved fire protection.

Installation types

There are three types of installations essentially:

• On plaster, in cable ducts, exposed carefully (for example, in basements, garages, attics, damp rooms, etc.)
• Laid under plaster, in conduits or in screeds (eg in residential and office spaces )
• In plaster, for example, with a land line in the plaster.

Standardize

In Germany the electrical installation is regulated by numerous VDE regulations and DIN standards. It is worth mentioning in particular the series DIN VDE 100, as well as the standard DIN 18015 in this context.

DIN VDE 0100 contains provisions for the design, construction and testing of electrical systems, both for residential as well as commercial and public buildings.

DIN 18015 contains information on electrical installations in residential buildings, the minimum equipment, planning principles, as well as routing and placement of equipment.

The Directive RAL -RG 678 extends DIN 18015th Depending on the requirements of comfort and energy efficiency in the Directive, set various standards. The classification starts with the identification by a star, which is the minimum configuration to DIN 18015-2, and extends to the labeling with 3 stars for discerning guests. The standards take into account functional areas such as Lighting control, shutter and blind control, individual room temperature control, heating and ventilation or burglar and fire alarms.

History

The first electric installations have been prevalent since about 1890 and were laid on plaster. They usually consisted of two twisted wires that were attached at a distance of about one meter with a small round and grooved ceramic cable carrier (porcelain). The cable carrier sat between the two wires, as is still in overhead line insulators usual. The electric lines themselves were coated with gutta-percha and a yarn braided or braided iron wires. The switches were made ​​of brass or copper and had housing made ​​of sheet metal, ceramic or early plastics ( bakelite ).

Later, the routing of lines in beaded, leaded sheet iron pipe ( Bergmann tube) with a Teerpapierisolierung on the inside was. Matching sheet metal junction boxes had a similar internal insulation and terminal blocks with screw terminals on ceramic carriers. For the production of large bending radii were adapted to the specific diameter of pipe pliers, with which it was possible to introduce a plurality of lined-up with less than 90 ° bends to produce a 90 ° bend. Narrow 90 ° angle bends consisted of half-shells which were installed after the lines were drawn.

Around 1920, came to the concealed wiring. The installation of pipes were produced out at the end with a so-called whistle, preferably white, smooth, rounded porcelain under the plaster - on the wall only the ceramic ring was visible.

The laying of individual wires in metal installation tubes lasted until the 1950s. Later, PVC sheathed copper cables were laid on the wall using Bakelitschellen or concealed. Junction boxes were nevertheless often on plaster and consisted of bakelite. Concealed also ribbon cable with parallel adjacent veins was used without sheath insulation.

The use of cheaper aluminum lines mainly in the GDR led to reliability problems due to the intermediate layers at the contact ( terminal points, switches, sockets ) and the increased risk of fracture. Appropriate terminals have been developed for aluminum and the installation required increased care: had to be cleaned and greased wire ends: addition had clamp connections should be retightened. The only secure connections for aluminum can crimp with appropriate ferrules. A compromise was copper-plated aluminum as conductor material ( AlCu ); Finally, the use of aluminum in house installations due to the risk of accidents (fire, unreliable links, in particular the PEN conductor ) was banned. Existing installations have grandfathered. The expansion of existing installations is problematic because current suitable for copper wire terminals are not suitable for aluminum.

Today installations are usually carried out with copper - sheathed cable, which are available in various cross-sections and wire numbers; this is done in plaster or in PVC and flame-retardant PP installation pipes.

The installation of pipes in plaster is subject to certain rules, so as to facilitate and to avoid accidental violating for example through holes in the walls of the finding.

Wiring circuits

• Elimination
• Series circuit
• AC circuit
• Change of control circuit
• Cross circuit
• Switch circuit