Regardless of the desired standard, every residential building requires general basic electrical equipment. This includes a house connection, power lines for electrical equipment, telecommunications lines, network lines, television lines, internal communication lines (e.g. for the door intercom), control cables (e.g. for roller shutter control) and the associated installations (switches, sockets, devices, etc.).
Due to the increasing mechanization of private households, the rapid developments in the communication sector and the increasing demand for building automation systems, the electrical planning of residential buildings is becoming increasingly complex. This bauwion knowledge page offers an initial overview of the basic planning of electrical equipment for residential buildings.
Conventional electrical installation or building automation: Many new residential buildings are now equipped with a bus system. The individual systems, such as heating, shading, ventilation, lighting control, etc., can thus be networked with each other without much cabling effort. But conventional electrical installation is still common. It is quite possible to plan a building with minimal technical equipment, whether for cost reasons or out of conviction, e.g. shading with manual drive, a simple doorbell and conventionally controlled lighting. It is also possible to integrate a bus system into a conventional electrical installation: If, for example, several light sources are to be switched individually in the living area, it makes sense to set up a bus system for these circuits, otherwise a large number of individual switches would have to be installed and operated, which could be confusing in daily use.
A conventional electrical installation will probably be part of the basic equipment of a new building for some time to come, but building automation is becoming more and more important. Due to these two options, it is all the more important to think through the electrical planning together with the client/user in detail at an early stage in order to be able to make the right decisions here.
Installation plans: Plans for electrical systems are usually to be drawn up in accordance with DIN EN 61082-1, using the symbols from DIN EN 60617.Since there are often short-term changes during the construction phase, e.g. due to kitchen or bathroom planning, it makes sense to adapt the installation planning to the finished state of the system after execution, i.e. to create up-to-date as-built plans. This makes it easier to carry out later conversion measures or troubleshoot.
Earthing systems: In principle, a foundation earthing rod must be installed in every new building in accordance with the specifications of DIN 18014, the installation is carried out by the shell construction company in coordination with the electrical company. Since the electrician is responsible for the functionality, he should accept the installation of the foundation earther before the foundation/floor slab is poured with concrete. See also documentation of grounding under Execution.
If a concrete foundation is designed with an increased earth transition resistance for structural reasons, a ring earthing rod can also be laid in the ground instead of the prescribed foundation earthing. This is the case with the design
In these cases, the necessary earth sensitivity of the earthing rod in the foundation is not given and a ring earthing rod with a functional equipotential bonding conductor must be laid, which corresponds to a foundation earthing rod. See ►Foundation earthing rods, installation examples and ►ring earthing rods, installation examples Grounding
rods are laid as a closed ring, for larger buildings with cross connections with a mesh size of no more than 20 x 20 m. In the case of a lightning protection system, the maximum permissible mesh size can also be smaller. Bare or galvanized strip steel of at least 30 mm x 3.5 mm or round steel with a diameter of at least 10 mm can be used as foundation earthing rods (and as functional equipotential bonding conductors). The foundation earthing rod is installed in the strip foundations of the outer walls or in the foundation slab and must be enclosed on all sides with at least 5 cm of concrete.
Ring earthing rods must be permanently corrosion-resistant and are usually made of stainless steel, but multi-stranded copper cables (bare or tin-plated) with a minimum cross-section of 50 mm² are also permitted. The ring earthing rod is installed in a moisture-permeable, frost-free area outside the foundations, e.g. in the excavation, below the foundation or outside a frost apron.
More detailed installation specifications and pictorial examples of foundation and ring earthing rods are listed in DIN 18014, which also contains a diagram "Decision aid for the execution of foundation earthing rods".
Electrical house connection: The connection of a residential building to the public electricity grid must be applied for in coordination with the electrical company from the distribution system operator or the utility company. It is advisable to clarify in advance which type of wall penetration (core drilling, protection, casing or casing pipe) the executing company prefers.
Since the airtight building envelope must be penetrated for all house connections, it makes sense to take into account a so-called multi-branch penetration already in the shell construction. In
accordance with DIN 18012, the following dimensions apply to the location of the electrical house connection on house connection walls and in house connection rooms:
Exceptions apply in flood-prone areas. In this case, the house connection, as well as the other components of the electrical connection (meter stations and circuit distributors) should be above the expected hundred-year flood height, or possibly a locally determined flood height that deviates from it.
House connection room: In addition to the electrical house connection, house connection rooms are usually also used for water, sewage, telecommunications and gas/district heating connections. They should comply with the requirements of DIN 18012. According to this, the house connection room must be easily accessible and not serve as a passage room. It should be located on the outer wall through which the pipes are led into the building, be at least 2 m high and 2 m long. When covering a wall, a width of 1.50 m is sufficient, if several walls are covered with installations, the width should be at least 1.80 m. The passage height under cables must not be less than 1.80 m and the lockable door must be taken into account with dimensions of 2.0 m x 0.875 m. In addition, a safety socket and permanently installed lighting must be provided.
In accordance with DIN 18012, a house connection room must be provided for all buildings with five or more usage units, but is also recommended for buildings with fewer usage units. House connections can also be installed in house connection niches in single-family houses without a basement or on house connection walls in buildings with up to 5 usage units. The exact requirements and dimensions of house connection walls and niches are also regulated in DIN 18012.
In a single-family home, in addition to the house connection device of the grid operator, the circuit distributor and the electricity meter are usually also housed in a distribution box in the house connection room.
In residential construction, the supply is divided among the individual apartments in a distribution box in the house connection room and routed to the individual units after the individual electricity meters via a line with three outer conductors and a permissible current carrying capacity of at least 63 A. In the individual apartments, a central small circuit distributor with the necessary overcurrent and residual current protection devices is usually installed in the hallway. Circuit distributors must be dimensioned according to the required equipment (number of rooms, lights, sockets, stove connection, washing machine, ...) and should have sufficient reserve spaces for subsequent installations.
The minimum number of circuits, sockets, connections and switches can be found in DIN 18015-2.
Slots and openings: In masonry construction, most electrical cables are laid in the masonry. DIN 18015-3 specifies the installation zones for this.
Slots and recesses are often subsequently chiseled into the finished masonry by the electrician. It should be noted, however, that the length and depth of the slots that can be allowed without proof is very limited: The permissible sizes for vertical or horizontal/oblique slots are specified in DIN EN 1996-1-1/NA (National Annex - Nationally Defined Parameters Eurocode 6: Design and Construction of Masonry Structures - Part 1-1: General Rules for Reinforced and Unreinforced Masonry). Accordingly, in an 11.5 cm thick masonry, horizontal and oblique slits are not permitted at all and subsequently constructed vertical slits are only permitted up to a depth of 10 mm and a width of 100 mm. Vertical slots and recesses that are already made during the construction of the wall are only permitted from a wall thickness ≥ 17.5 cm.
Horizontal/slanted slits of 15 mm depth are only permitted in unlimited length from a wall thickness ≥ 24 cm, from a depth of 25 mm the length is limited to 1.25 m for all wall thicknesses. The exact values for the reference of wall thickness, slot depth and slot length can be found in tables NA.19 and NA.20 of DIN EN 1996-1-1/NA.
Pipe networks: In contrast to the lines for power supply, all lines for information, communication, radio and television technology must be laid in pipe networks. This also applies to high-voltage systems. Since technology is constantly evolving, especially in the field of telecommunications and the Internet, this makes sense, as it allows the system to be expanded or modified in the future. When planning the pipe networks, it should be noted that pipes are not longer than 12 m and do not have more than 2 bends in their course. After 12 m at the latest, boxes or cans must be planned. This ensures that cables can be pulled or replaced. Further requirements for the pipe network are regulated in DIN 18015-1.
Cable routing over roof: For cables penetrating the roof membrane, early planning makes sense in order to keep the number of penetration points low. These must be sealed particularly carefully. However, attachment points for roof mounts, such as satellite dish stands or photovoltaic systems, must also be professionally executed and must therefore be fixed at an early stage, especially for flat roofs.
Fire protection for pipeline systems: The Model Pipeline System Directive (MLAR) has been introduced as a technical building regulation in most German federal states and is therefore legally binding. It specifies fire protection requirements for cable systems, in particular also for electrical cables. The MLAR is based on the requirements of the MBO (Model Building Code) and is intended to prevent smoke and fire from spreading through penetrating pipes in the event of a fire or that pipes impair the fire resistance of sealing components.
Accordingly, the following applies to all cables in necessary stairwells, in spaces between necessary stairwells and exits to the outside and in necessary corridors (except in open corridors in front of external walls):
: Except for buildings of building classes 1 and 2, within an apartment and within a usage unit ≤ 400 m² on a maximum of two floors, the following applies to all pipes that run through room-enclosing components with prescribed fire resistance:
Functional integrity in the event of a fire: The Model Pipeline Systems Directive (MLAR) also prescribes functional maintenance of the pipeline systems for safety-related systems and facilities prescribed by building regulations, such as SHEV systems or emergency lighting. This is to ensure that these systems remain undamaged and functional for a sufficiently long time in the event of a fire. For example, for water pressure booster systems for extinguishing water supply or mechanical smoke extraction systems, a functional integrity of 90 minutes may be prescribed. A functional integrity of 30 minutes may be prescribed, e.g. for emergency lighting systems, passenger lifts with fire control, fire alarm systems including the associated transmission systems and natural smoke extraction systems.
This functional integrity can be achieved if the pipes have functional integrity class E 30 or E 90 or if they are laid on the raw ceiling with at least 30 mm of screed cover or in the ground. Alternatively, cables can also be laid in the so-called ring bus system.
Energy efficiency: Many new buildings today are equipped with a complete building automation system (known as a "bus system") that controls all electronic processes and thus enables a particularly energy-efficient use of heating, electricity and water. But energy-saving measures are also possible with conventional electrical equipment:
Lightning protection: A lightning protection specialist company should be commissioned to plan a lightning protection system.
A lightning protection system usually consists of an outer and an inner lightning protection. External lightning protection is usually only necessary for residential buildings in larger apartment buildings or in an exposed location that is at risk of impact.
As a rule, a lightning protection system must comply with the specifications of the current DIN EN 62305 series of standards in Parts 1 – 4 (with the associated VDE classifications VDE 0185-305 Parts 1 – 4), including the applicable corrections and supplements, and must have a (corrosion-resistant) equipotential bonding in accordance with DIN VDE 0100-540 on the foundation earthing rods.
For internal lightning protection, three-stage protection makes sense, see ► Surge protection. In this case, the coarse and medium protection must be carried out by the electrical company. For fine protection, mobile surge protection plugs (category SPD type 3) are usually sufficient to protect individual valuable small appliances in the household.
[...] ... read more on bauwion - BauWissenOnline
Documentation of earthing : The foundation earthing earth must be removed by the electrical company before concreting the foundation. For this purpose, the installation is documented and a continuity measurement is carried out. The documentation must contain:
This documentation and the continuity measurement guarantee the functionality of the earthing system, as any defects can usually no longer be remedied after the concrete has been laid.
In DIN 18014, a form for the documentation of the foundation earthing can be found as Annex A.
Installation process: The installation of the basic electrical equipment is roughly divided into two phases:
DIN 18012 House connection devices in buildings — General planning principles
DIN 18013 Niches for meter places (meter cabinets) for electricity meters
DIN 18014 Foundation earthing rods — General planning principles
DIN 18015-1 Electrical installations in residential buildings - Part 1: Planning principles
DIN 18015-2 Electrical installations in residential buildings - Part 2: Type and scope of minimum equipment
DIN 18015-3 Electrical installations in residential buildings - Part 3: Cable routing and arrangement of equipment
DIN 18015-4 Electrical installations in residential buildings - Part 4: Building control technology
DIN 18015-5 Electrical installations in residential buildings - Part 5: Airtight and thermal bridge-free electrical installations
DIN EN 1996-1-1/NA National Annex — Nationally Determined Parameters — Eurocode 6: Design and Construction of Masonry Structures — Part 1-1: General Rules for Reinforced and Unreinforced Masonry
DIN EN 61082-1 Electrical Engineering Documents — Part 1: Rules
DIN EN 62305-2 Lightning Protection — Part 2: Risk Management
DIN EN 62305-3 Lightning Protection — Part 3: Protection of Structures and Structures
DIN EN 62305-4 Lightning Protection - Part 4: Electrical and Electronic Systems in Buildings
RAL-RG 678, Electrical Systems in Residential Buildings — Requirements
Model Wiring System Directive (MLAR)
► Elektro-Plus Information Brochures
Source: bauwion
