IEC – German Standard Typical residential wiring diagram issued from VDE 0100 requirements for electrical installations

IEC – German Standard
Typical residential wiring diagram issued from VDE 0100 requirements for electrical installations.

SUPPLY
May be single phase (230 V-50 Hz) or - in the majority of cases - 3 phases (400 / 230 V-50 Hz). Max. Tolerance (voltage): + 6% / -10%. TN- and TT- systems are in use. TT- systems are the most common in domestic installations. There is usually one meter. Facilities are provided with a second meter for special tariffs, etc. A fuse isolator unit allows all phases to be cut-off, isolating the whole domestic installation.

DISTRIBUTION BOARD
The distribution board usually contains pre-fuses (for example 3 x 32 A), RCBO 30 mA for household applications (1 or 3 poles). Transformer(s) as for entry door systems, MCB (16 A for general circuits up to 32 A (3 poles) for (water) heating systems). Time lag switches in dwellings. These devices are all mounted on a DIN-Rail.

POWER CIRCUITS
Single phase up to 3 WA, 7.3 KVA: 3 phases. Electrical appliances having a high power consumption (cookers, washing machines, etc.) are supplied via a specific circuit and connected either to 16 A socket-outlet or cable outlet or to a specific socket Perilexi or CEE 17. It is not uncommon to find 3 phases appliances. Protection rating and cable size of each circuit are calculated according to the appliance (min section 1.5 mm2 Cu 16 A).

GENERAL CIRCUITS
These circuits supply both lighting points and socket outlets. The rating of the protective device is usually 16 A. There is no limitation of the number of outlets on a circuit. This limit is calculated according to expected/probable use of the circuit. Socket outlets are generally of the 2P+E type “German". These plugs are non-polarized. All German socket outlets are earthed. In general, the protective conductor is distributed throughout all circuits. For class II devices < 2.5 A, the Euro-plug is used. The wire cross-section of the fixed installed cables is normally 1.5mm² (protected by a 16 A Circuit Breaker).

DAMP & OUTDOOR
INSTALLATIONS
Special rules apply, in particular for IP rating of accessories and equipment and RCD Protection.

EARTHING
Earthing is local, usually through a foundation earthing arrangement. All metallic services shall be bonded (gas and water pipe, heating, waste systems, etc.) with a 10 mm2. In bathrooms the local equipotential bonding could have a cross sectional area of 4 mm2. Neutral is re-earthed in the control panel. A protective conductor is distributed to all socket outlets.

INSTALLATION RULES
The installation must comply with the requirements of VDE 0100 and the “TAB” (TAB = technische Anschlussbedingungen = special requirements of the energy supplier, for example EON, RWE, EnBw or Wattenfall). Installations may only be erected by registered and qualified electricians.

BATHROOMS
Special rules apply to bathrooms. The room is divided into different zones:

Zone “Bereich 0”: Electrical equipment are not allowed. Only special SELV-devices, max.12V AC or max. 30V DC are allowed. The power supply for these SELV-circuits is not allowed in “Bereich 0” and in “Bereich 1”.

Zone “Bereich 1”: Only fixed installed electrical equipment for hot water production and SELV or PELV –devices (max. 25V AC or max. 60V DC) are allowed. The power supply for the SELV- or PELV -circuits has to be installed outside “Bereich 0” and in “Bereich 1”.

Zone “Bereich 2”: Only Electrical equipment supplied by SELV- or PELV (max. 25V AC or max.60V DC) are allowed. Only shaver sockets according to DIN EN 61558-2-5 are allowed. In bathrooms, an additional equipotential bonding and RCDs (30 mA) protection for socket outlets are mandatory (Details in the DIN VDE 0100-701).

HOME AND BUILDING CONTROL
KNX (EIB) ISO/IEC14543, EN50090 is common in big and luxury installations.

ACCESSORIES
They shall comply with the appropriate VDE standards. Flush accessories are fitted in boxes. Claw-mounting and screw-mounting are used.

ENERGY SAVING & REGENERATIVE POWER GENERATION
Single-room heating control and time-controlled hot water supply is mandatory due to the EnEV (energy saving directive). Airproof installations are common in low energy buildings. More and more roofs are equipped with photovoltaic cells