Deploying charging stations for your electric vehicle: what pitfalls should you avoid?

February 24, 2022

🔋 Terminal power

This is a very important point: having enough power to recharge your electric vehicle is a concern for many electro-mobilists. It's essential to match the power of the charging station to that of the vehicle.

🔌 Reminder: There are two different types of current, alternating current (AC) and direct current (DC) :

• DC current enables a high-power electric vehicle to be charged. Charging time is therefore considerably reduced. A DC charger can charge a car up to 350 kW in some models. DC charging stations are already equipped with a converter. In other words, it's up to the terminal itself to convert alternating current into direct current.
  

• AC current, on the other hand, is limited; it's a periodic current that changes direction twice per period. Charging time is therefore much longer. On the other hand, an AC charger can charge a vehicle up to 22 kW. Finally, for this type of current, the electric vehicle must be fitted with an on-board charger called a converter, which transforms the alternating current into direct current.

For more details on these two currents, please read the article "AC and DC terminal - what's the difference?"

It's important to take into account the vehicle's characteristics, as not all cars accept the same power. The new Renault ZOE, for example, is limited to 50 kW.

Below is a diagram of an electric car with a maximum power rating of 110 kW.

• In the case below, there's no need to install a charging station with a power rating greater than 110 kW DC. A 150 kW DC charging station will not accelerate charging if the vehicle is limited to 110 kW. However, in the same case, a charging infrastructure delivering 50 kW DC is less efficient than one delivering 100 kW DC.
  

• In the same example, the vehicle's inverter accepts 11kW AC power. In a similar example, having a charging station delivering 22 kW AC power does not accelerate vehicle charging if the vehicle is limited to 11 kW AC.

📜 Regulations for covered parking lots (ERP)

Electrical installations in covered parking lots are subject to several conditions:

• The decree of May 9, 2006 (article PS 23): This decree sets out specific measures for indoor parking lots. It was drawn up with fire risks in mind. It briefly lists the rules to be respected if the parking lot is "non-sprinklered", i.e. not equipped with an anti-fire system.

There are two types of situation:

• When a parking lot is not equipped with such a system, electrical installations must be limited to a maximum of 20 charging points per compartment, and a maximum simultaneous power output per compartment of 150 KVA.
  

• On the other hand, compartments equipped with sprinkler-type automatic water extinguishing systems, or water mist systems subject to the approval of the Safety Commission, are not limited in terms of maximum cumulative power or number of charging points.

These restrictions apply to public-access establishments (ERP) of the PS type, as well as to parking lots in high-rise buildings (IGH).

Obviously, this law does not apply to uncovered pitches, terraces and widely-ventilated parking areas.

A second requirement dedicated to covered parking lots is depicted in this act. It states that all electrical installations must be installed at the reference level or at the level above/below the reference level. In other words, an electrical terminal can only be installed at levels 0, 1 and - 1 of a covered parking lot.

⚡️ Isolated load points

If the charging point is insulated, the operator must comply with the following conditions:                                                                                                                                                                        

• Clear identification of locations
• A distance of 6 spaces must be maintained between the charging points and the space not dedicated to electric charging (or a minimum distance of 15 m);
• A 6 kg water-based fire extinguisher near each charging point;
• A general emergency cut in the power supply to the charging points.

⚡️⚡️ Grouped load points

If the charging point is grouped together, the operator must meet the following requirements:

• Clear identification of locations;
• A maximum of 10 charging points per station;
• The charging station must be separated from other areas by PF 1 h or E60 walls (R60 if load-bearing walls);
• The proximity of 2 x 6 kg water extinguishers;
• An emergency power cut.

‍