Electrical installation

Electrical Installation - Electrical installation encompasses a building’s entire electrical system, from the service line through the distribution and protection systems to the individual circuits, switches, and outlets. In real estate transactions, the condition of the electrical installation is a key factor in determining value, as outdated systems pose significant safety risks and entail high renovation costs.

Regulatory Requirements and Issues with Older Buildings

The electrical requirements for building installations are regulated by the DIN VDE 0100 series of standards. These standards establish minimum requirements for protection against electric shock, overcurrent protection, wire sizing, and the number of circuits. In addition, DIN 18015 defines the equipment standards for electrical systems in residential buildings and distinguishes three levels: minimum equipment, standard equipment, and comfort equipment.

In existing buildings constructed before 1970, the electrical installations often no longer meet current technical standards. Typical deficiencies include neutralization systems (classic TN-C neutralization), in which the protective conductor and neutral conductor are combined and no separate protective conductor is present at the outlets. Residual current circuit breakers (RCDs) are completely absent in many older buildings, even though they are required by current standards for all outlet circuits. Other common deficiencies include inadequate circuit protection with too few circuits, outdated fuses instead of circuit breakers, aluminum wiring with brittle insulation, and junction boxes without proper terminal connections.

These deficiencies are not only problematic from a regulatory standpoint but also pose a real safety risk. According to the Institute for Loss Prevention and Loss Research (IFS), a significant proportion of all residential fires can be attributed to defective or overloaded electrical installations. Landlords are required under the Industrial Safety Regulation to maintain the electrical system in a safe condition. An E-Check-a standard-compliant inspection of the entire electrical system by a licensed electrical contractor in accordance with VDE guidelines-provides insight into the condition of the system and systematically documents any defects.

Electrical Installation - Equipment Levels According to DIN 18015

Equipment Level	Outlets per Living Space	Special Features	Suitability
Minimum Equipment	3-5	No dimmer, no LAN	Basic standard, older building
Standard equipment	6-8	RCD, separate circuits	Contemporary living standards
Comfort equipment	9+	Bus system, smart home, dimmers, LAN	New construction, high-quality renovation

Costs and scope of a renovation

The complete renovation of an electrical installation is one of the most cost-intensive renovation measures for existing buildings. The costs for a complete new installation, including new wiring, sub-distribution panels, outlets, and switches, typically range between 80 and 120 euros per square meter of living space. For a single-family home of 140 square meters, this results in a cost range of approximately 11,000 to 17,000 euros; for a multi-family home with several residential units, the costs are correspondingly higher.

The costs generally include the new meter system, a standard-compliant sub-distribution panel with circuit breakers and ground-fault circuit interrupters (GFCIs), the rewiring of all circuits with sufficient conductor cross-section, modern outlets and switches, as well as equipotential bonding. Additional costs arise for restoring plaster and wall surfaces after grooving, which is why an electrical renovation is ideally coordinated with other renovation measures.

Practical Tip for Nuremberg and Franconia

In the Nuremberg metropolitan region, a significant proportion of residential buildings date from the post-war reconstruction period of the 1950s and 1960s, and their electrical installations are in urgent need of renewal. Particularly in the Nuremberg districts of Gostenhof, Steinbühl, and St. Johannis, as well as in older residential complexes in Fürth and Erlangen, we regularly encounter installations with traditional neutral grounding and missing GFCI circuit breakers. We recommend that prospective buyers have an electrical inspection performed by a licensed electrical contractor before purchasing an existing property. The cost for a residential unit is approximately 150 to 300 euros and provides a reliable basis for calculating renovation costs. For condominiums, it should also be clarified whether the common areas (riser pipes, main distribution panel, stairwell lighting) meet current technical standards, as any renovation must be decided upon and financed by the condominium association.

Frequently Asked Questions

Is an E-Check mandatory for rental properties?

There is no legal obligation in Germany to perform an E-Check on a regular basis. However, under the Industrial Safety Regulation and the Civil Code, the landlord is obligated to maintain the rental property in a safe condition-and this includes a functioning and safe electrical installation. In the event of damage, the landlord may be held liable if the system was recognizably defective. We recommend that landlords have an E-Check performed every four years and archive the inspection report.

Does an old electrical system have to be replaced when there is a change of ownership?

There is no general obligation to replace the electrical system when there is a change of ownership. Grandfathering means that a system that complied with the standards in effect at the time of its installation may continue to be operated. However, this grandfathering provision does not apply in the event of significant changes or expansions to the system. We nevertheless recommend including the replacement costs in the purchase price calculation for buildings with installations dating from before 1970, as retrofitting will become unavoidable in the medium term.

What signs indicate an outdated electrical installation?

Clear indicators include fuses instead of circuit breakers in the fuse box, missing ground-fault circuit interrupters (GFCIs), outlets without a grounding prong (two-pole), fabric sheathing or brittle rubber insulation on visible wires, as well as flickering lights or fuses blowing during normal use. A low number of outlets per room and the lack of separate circuits for large appliances such as stoves, washing machines, and dryers also indicate an outdated installation.

How much does it cost to retrofit a wallbox, and what are the requirements for the electrical installation?

A wallbox for electric vehicles (11 kW charging capacity) requires a dedicated circuit with a 16 A fuse and a sufficiently sized supply line from the building service entrance. Older electrical installations in existing buildings in Nuremberg from the 1960s or 1970s often lack both the necessary cable capacity and free space in the fuse box for an additional circuit. The retrofitting costs for a wallbox, including the necessary electrical work, range from 800 to 3,000 euros depending on the existing system-and even more if extensive renewal of the supply line is required. Under the KfW Program 442 (Charging Stations for Electric Vehicles), private owners and condominium associations can receive grants for installation, provided that photovoltaic systems or a charging station control system are also planned. Condominiums in homeowners’ associations require a resolution from the owners’ meeting to install a wallbox in the underground garage-however, since the 2020 homeowners’ association reform, individual owners have been entitled to permission.

Back to the Real Estate Glossary.