The electrical system to install wallboxes and columns

The electrical system for the installation of charging solutions for electric vehicles is subject to compliance with certain regulations and consequently to special safety measures.

We assume that the power supply circuits of the recharging systems and the relative protection devices must comply with the requirements of Section 722 “Power supply for electric vehicles” of the CEI 64-8 standard.

Charging modes 3 and 4 of electric vehicles, defined in the CEI EN 61851-1 Standard, require a dedicated power supply and charging equipment that incorporates the control and communication circuits.

Special security measures

The legislation provides for special measures for the safety of recharging points:

  • the protection of each connection point with a differential device with rated intervention current not exceeding 30 mA, type A, together with a suitable device that ensures the interruption of the power supply in the event of a fault current in direct current (DC) higher than 6 mA, or a type B differential switch;
  • each connection point must be powered individually by a terminal circuit and must be protected by its overcurrent protection device (this means that the terminal circuit must power only the system designed to charge the electric vehicle).
  • the sizing of the circuits must take place with a factor of contemporaneity and use equal to 1.

Surge protections

As regards the protection against over voltages of atmospheric origin or manoeuvre (paragraph 722.443) it is strongly recommended that the power supply circuit of the charging point be protected with a surge limiting device (SPD), this to prevent possible damage to the electric vehicle. or to the charging system.

Utilization factor

Utilization factor is the ratio, expressed as a numerical value or percentage, of the maximum utilization of a circuit or groups of circuits within a specified period, concerning the total installed power of the circuit.