All you need to know about NF C 15-100

What is the NF C 15-100 standard?

NF C 15-100 is a French technical standard published by UTE (Union Technique de l'Électricité), the national electrical standards body affiliated to AFNOR (Association Française de Normalisation). For foreign readers, AFNOR plays a role in France equivalent to that of BSI in the UK, DIN in Germany or ABNT in Brazil: it is the official guarantor of national technical standards.

This standard defines the rules for the design, construction and testing of low-voltage electrical installations (less than 1,000 V AC) in residential buildings. It covers single-family homes as well as apartments, the common areas of apartment buildings and business premises attached to a dwelling.

Its last major revision dates back to 2002, with regular updates (notably in 2010 and 2015) to incorporate technological developments such as home automation, renewable energies and electric vehicle charging stations.

Why is this standard important? It is made compulsory by several mechanisms:

• Consuel (Comité National pour la Sécurité des Usagers de l'Électricité), the body responsible in France for certifying the conformity of new installations before the electric meter is commissioned, requires compliance;
• Home insurers use it to assess liability in the event of an electrical claim;
• real estate diagnostics (DPE, electrical diagnostics) check the main points when selling.

The main principles of standard NF C 15-100

Protecting people first and foremost

The first objective of the standard is to protect occupants against the risks of electrocution and fire caused by electrical sources. To achieve this, it imposes a hierarchy of protections:

• The main switchboard (or distribution board) contains all the switching and protection devices. It must be easily accessible, installed in a dry place and out of the reach of young children.

• Differential circuit breakers (also called differential switches in France) cut the circuit in the event of current leakage to earth, protecting people against electric shocks. The standard requires 30 mA differentials in damp rooms and for most domestic circuits.

• Protective circuit breakers protect each circuit against overloads and short circuits.

The concept of specialized circuits

The standard distinguishes between circuits according to their use. Each energy-consuming or high-risk appliance must have its own dedicated circuit, sized in terms of cable cross-section and circuit-breaker rating. These are the specialized circuits required in a dwelling:

• Cooker or hob: 6 mm² circuit, 32 A circuit breaker

• Washing machine: 2.5 mm² circuit, 20 A circuit breaker

• Dishwasher: 2.5 mm² circuit, 20 A circuit breaker

• Electric water heater: 2.5 mm² circuit, 20 A circuit breaker

• Freezer: 1.5 mm² circuit, 16 A circuit breaker (recommended)

• Integrated oven: 2.5 or 6 mm² circuit, depending on power rating

This organization avoids the risk of overloading and facilitates maintenance.

Minimum number of sockets and light points

The standard sets a minimum number of socket outlets and lighting points per room, depending on surface area:

Safety zones in the bathroom

The bathroom is given special treatment in the NF C 15-100 standard, as it is the room where the electrical risk is highest due to the simultaneous presence of water and electricity. The standard defines four protection volumes:

• Volume 0: the inside of the shower tray or bathtub. No electrical equipment is allowed.

• Volume 1: above the shower tray, up to 2.25 m high. Only very low-voltage (12 V) equipment and devices specifically designed for this volume (IPX5 minimum) are permitted.

• Volume 2: 0.60 m zone around volume 1. Devices must be Class II (double-insulated) and have a minimum IPX4 rating. Shaver sockets powered by isolating transformers are permitted.

• Volume 3 (deleted in 2015 revision): formerly the area between 0.60 m and 2.40 m beyond volume 2.

Outside the building, standard electrical outlets are permitted, provided they are fitted with a protective shutter.

Earthing and the electrical panel

Grounding

Every dwelling must have an earth connection to all metal grounds (lights, appliances, metal pipes) and to the protective conductor (green/yellow wire) of each circuit. The resistance of the earth connection must be less than 100 O, and ideally less than 50 O, to ensure proper operation of the differential devices.

The composition of the electrical panel

According to the standard, the table must include :

• A connection circuit breaker (or head circuit breaker) which forms the boundary between the electricity supplier's network and the private installation;

• One or more 30 mA differential switches (AC type for common uses, A type for circuits containing electronic equipment such as chargers, inverters and UPS);

• Divisional circuit breakers protecting each circuit;

• A lightning arrester mandatory in areas with high lightning exposure (classified in France according to an official map of keraunic levels).

The standard also recommends a communication board (grade 1 to 3 depending on requirements) to group together computer, TV and telephony network equipment, in accordance with NF C 15-100-11 dedicated to residential communication networks.

Special features for the kitchen

The kitchen is the room with the most specialized circuits. In addition to the devices already mentioned, the standard requires :

• at least 4 double socket outlets for small appliances, above the worktop

• an independent lighting circuit
• a ground connection on all metal equipment (sink, hood, etc.).)
• 30 mA differential protection for all circuits.

For kitchens equipped with an induction hob, we recommend using a 6 mm² cable, even if the appliance's power rating is less than 7,200 W, to anticipate the possibility of replacing it with a more powerful model.

Verification and compliance: the role of Consuel

In France, all new or completely renovated electrical installations must be checked by the Consuel before being put into service. Consuel is a non-profit organization mandated by the public authorities to carry out this mission. It issues a attestation of conformity (often called a "Consuel visa"), without which the network operator (Enedis, formerly ERDF) cannot commission the meter.

For foreign readers, this system has no universal equivalent. In the UK, it's Part P of the Building Regulations that plays a similar role; in Belgium, it's the RGIE (Règlement Général sur les Installations Électriques); in Quebec, it's the Construction Code and Hydro-Québec that verify compliance.

The Consuel verification procedure includes :

1. Installation by a qualified electrician or by a private individual on request

2. Submission of a declaration of work accompanied by a plan of the installation

3. An on-site inspection visit if justified by a draw or doubt

4. Issuance of the green certificate (new housing) or blue certificate (renovation)

Recent developments: home automation, EVs and renewable energies

The NF C 15-100 standard has evolved to incorporate the new realities of connected buildings and the energy transition:

• Charging stations for electric vehicles (IRVE): since 2020, all new housing or major renovations must include the pre-positioning of a dedicated circuit for a charging station, in accordance with the LOM law (Mobility Orientation Law). The terminal itself must be installed in accordance with NF C 15-100 and certified by a qualified IRVE installer.

• Photovoltaic generation: inverters and grid connection devices must comply with specific protection rules integrated into the annexes to the standard.

• Home automation and energy management systems: the standard provides for dedicated spaces in the electrical panel for control modules (load shedding, off-peak management, etc.).).

Conclusion

The NF C 15-100 standard is much more than an administrative constraint: it's an everyday safety tool. It guarantees that your electrical installation is sized to meet your needs, protected against the risks of fire and electrocution, and ready to accommodate tomorrow's equipment. Whether you're hiring a professional electrician or doing the work yourself, knowing the basics will help you make the right decisions and demand the right materials.

For major work, don't hesitate to consult a certified professional and check that the materials used (circuit breakers, cables, panels, sockets) comply with current standards and bear the CE and NF markings.