Electrical installation usually refers to electrical systems for low and extra-low voltage and signal transmission and their production. In a narrower sense, this is understood to mean the power supply for electrical equipment such as lighting in building or house installation . However, similar processes and materials are also used in industrial plants and control cabinets as well as in means of transport .
The electrical installation comprises the wiring and the installation of manifolds , the overcurrent protection devices , RCDs , circuit breakers , lights , electrical appliances , electrical equipment , sensors such as motion detectors and twilight switches , circuit breakers , switches and sockets , as well as the final measurement of the effectiveness of protective measures .
It is the job of the electrician to connect the individual components in such a way that the circuit fulfills the desired function and there is no risk of electric shock . When working, the relevant safety rules, especially the five safety rules , must be observed to avoid electrical accidents .
The minimum number of sockets and circuits per room and apartment is specified in DIN 18015 and RAL-RG 678 .
There are basically two ways of planning and setting up electrical installations:
The advantage of the central electrical installation is that all important equipment is combined in a distributor, which enables quick troubleshooting. The disadvantage here is that the mostly long line lengths to the consumers must be precisely dimensioned in order to keep voltage drops as small as possible.
With decentralized electrical installation, the equipment is arranged close to the consumers, which means better system clarity and significantly fewer cables and lines. In addition to the lower costs, an advantage is also the significantly improved fire protection .
There are essentially three types of installations:
- on plaster , in cable ducts, exposed (e.g. in basements , garages , attics , damp rooms, etc.)
- laid under plaster, in protective pipes or in screed (for example in living rooms and offices)
- in the plaster, for example with a ribbon cable in the plaster.
The first electrical installations were widespread since around 1890 and were laid on plaster . They usually consisted of two twisted cables, which were attached about one meter apart with a small, round and grooved ceramic cable carrier (porcelain). The cable carrier sat between the two wires, as is still common today with overhead line insulators . The electric cables themselves were sheathed with gutta-percha and iron wires wound or braided with a thread; color coding of the veins was not yet common. The switches were made of brass or copper and had housings made of sheet metal, ceramic or early plastics ( Bakelite ).
Later, the lines were laid in flanged , leaded sheet iron pipe ( miner's pipe ) with tar paper insulation on the inside. Matching sheet metal junction boxes had the same interior insulation and terminal blocks with screw terminals on ceramic supports.
For the production of large bending radii, there were special pliers, matched to the diameter of the pipe, with which it was possible to make several bends in a row with less than 90 ° in order to produce a 90 ° angle. Tight 90 ° bends consisted of angle half-shells that were installed after the lines had been pulled in.
Concealed installation came up around 1920 . The installation pipes are at the end with a so-called pipe , projecting out, preferably of white, smooth, rounded porcelain under the plaster - on the wall only of the ceramic ring was visible.
The laying of individual cores in sheet metal installation pipes lasted until the 1950s. Later, PVC- sheathed copper cables were laid on the plaster with Bakelite clips or under plaster, but junction boxes were often plastered and made of Bakelite. In the plaster, ribbon cables with parallel cores without jacket insulation were also used. With the transition to the new insulation material, the color coding of the cores also became established, but was not so strictly observed at first.
The use of cheaper aluminum cables, mainly in the GDR , led to reliability problems due to the risk of breakage and the oxide layer that forms on the bare aluminum, which can cause the contact points in distributors, switches and sockets to heat up and a cable fire . The wire ends had to be cleaned and greased and the clamp connections had to be tightened regularly. Only connections with crimp sleeves filled with grease were permanently reliable . As a compromise, copper-plated aluminum was used as the conductor material (AlCu). Today's terminals used for copper conductors are only suitable for aluminum if the manufacturer expressly allows this.
Today installations are mostly carried out with copper sheathed cables, which are available in different cross-sections and numbers of wires. Alternatively, cheaper copper - clad aluminum cables (CCAs) are used (which have a larger cross-section with the same current-carrying capacity). The sheathed cable is in plaster or in PVC or flame-retardant PP - installation pipes made.
When laying cables in the plaster , fixed installation zones must be observed in order to make it easier to find them later and to avoid accidental damage, e.g. through drilling holes in the walls. Old pipe networks are often not yet designed in accordance with these rules, so in old buildings it is advisable to use appropriate location devices before holes are drilled or nails are hammered in.
After an electrical system has been set up, test reports in accordance with DIN VDE 0100-600 must be prepared.
Further documentation is not explicitly specified, but arises from the necessity that the system operator must be able to prove the required technical safety of the electrical system and compliance with the generally recognized rules of technology . Also, for later maintenance work, a service technician "must be able to get a good overview of the system parts in a reasonable time even without precise knowledge of the location and the system". The VOB C , DIN 18382 section 3.1.7 speaks of a "necessary documentation", which is not detailed. On the other hand, DIN VDE 0100-710 provides detailed information on the required documents specifically for installations in medical areas.
The execution of circuit diagrams, diagrams and tables is based on DIN VDE 0100-510 as well as DIN EN 61346-1 and DIN EN 61082. The following should be documented:
- Nature and structure of the circuits (connected consumers; number and cross-section of the conductors, length of the circuits, type of cable or line routing; installation locations of invisible devices)
- Description of the protective, isolating and switching functions and their arrangement (in particular the type and type of protective devices and their rated current or setting value, expected short-circuit currents and breaking capacity)
The Low Voltage Connection Ordinance (NAV) of 2006 stipulates that electrical systems must be installed, expanded, modified and maintained in accordance with the generally recognized rules of technology . According to Section 49 (2) No. 1 of the Energy Industry Act , it is particularly necessary that the technical rules of the Association of Electrical, Electronic and Information Technologies e. V. (VDE) must be observed. The materials and devices used generally correspond to the generally recognized rules of technology if they bear the prescribed CE mark or, alternatively, the mark of an accredited body, such as the VDE or GS mark.
In addition to the electricity network operator himself, work on the system may only be carried out by an installation company entered in a network operator's list of installers (this generally applies to all specialist and master craftsmen).
On the other hand, maintenance work in the system part after the measuring device may also be carried out by laypeople, provided that no changes are made to the system. The occupational health and safety guidelines, on the other hand, generally require that operational maintenance work be carried out by a person trained in electrical engineering (EuP).
In Germany, electrical installation is regulated by numerous VDE regulations and DIN standards . In this context, the standards of the DIN VDE 0100 series and the standards of the DIN 18015 series are particularly noteworthy.
DIN 18015 contains information on electrical systems in residential buildings, their minimum equipment, planning principles, as well as cable routing and the arrangement of equipment.
The guideline RAL-RG 678 extends DIN 18015. The guideline defines various standards depending on the requirements for comfort and energy efficiency . The classification starts with the identification with a star, which corresponds to the minimum equipment according to DIN 18015-2, and extends to the identification with 3 stars for high demands. The standards take into account functional areas such as B. lighting control, roller shutter and blind control, individual room temperature control, heating and ventilation or burglary and fire alarms.
- Josef Pichler: Fire load-reducing measures and preventive fire protection in the technical infrastructure of office buildings  , Munich (2003); ISBN 978-3-638-26413-6 .
- DIN VDE 0100-600: 2008-06 Installation of low-voltage systems - Part 6: Tests 61.4 Creation of a test report on the initial test; see sub-items 61.4.1 to 61.4.5 on page 137 in Stefan Euler: Documentation of electrical systems , magazine Elektropraktiker, Berlin 64 (2010) 2
- Stefan Euler: Documentation of electrical systems , journal Elektropraktiker, Berlin 64 (2010) 2, pages 134 to 137; In: Elektropraktiker.de; accessed in December 2019
- DIN VDE 0100-510: 2007-06 Selection and installation of electrical equipment - General requirements, 514.5 Circuit diagrams; see sub-items 514.5.1 and 514.5.2 on page 137 in: Stefan Euler: Documentation of electrical systems , Zeitschrift Elektropraktiker, Berlin 64 (2010) 2; In: Elektropraktiker.de; accessed in December 2019
- Quotation from the NAV : "Materials and equipment that have been lawfully manufactured or placed on the market in another member state of the European Union or Turkey or a member state of the European Free Trade Association, which is a party to the Agreement on the European Economic Area and which do not comply with the technical specifications of the marks mentioned, including the tests and inspections carried out by the aforementioned states, are treated as equivalent if the required level of protection is achieved with them on an equally permanent basis. "
- VDE regulations - News from the VDE. (PDF) (No longer available online.) Archived from the original on March 8, 2014 ; Retrieved May 11, 2013 (1036 KB). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- Building standards dictionary - search. Retrieved May 11, 2013 .
- Norms Hager. Retrieved May 11, 2013 .
- DIN VDE 0100 series of standards erection of low-voltage systems ( VDE-Verlag )
- Schröder, Bernd: What is what in DIN VDE 0100? , 5th edition, 2020, ISBN 978-3-8007-5278-2 .
- Schmolke, Herbert: DIN VDE 0100 correctly applied , 7th edition, 2016, ISBN 978-3-8007-4194-6 .
- Hörmann, Werner / Schröder, Bernd: Protection against electric shock in low-voltage systems , 4th edition, 2010, ISBN 978-3-8007-3190-9 .
- Hübscher, Heinrich / Jagla, Dieter / Klaue, Jürgen: Expertise electrical installation , 1st edition, 2000, ISBN 3-14-221630-8 .
- Hans Schultke, Michael Fuchs: ABC of electrical installation . 15th edition, 2012, ISBN 978-3-8022-1055-6 .