EV charging: wallbox and reinforced socket

Reinforced socket (tomada reforçada). A socket made for charging, used with the cable that comes with the vehicle. We fit the Legrand Green'Up, which the manufacturer rates for charging at up to 3.7 kW (16 A, single-phase); the actual power depends on the vehicle's cable. It suits low daily mileage or a full night available for charging.

Wallbox. A fixed charging station with a Type 2 connection, which communicates with the vehicle and regulates the current: this is what is called mode 3. On single-phase it reaches 7.4 kW (32 A); on three-phase, 11 kW (16 A) or 22 kW (32 A). The vehicle's on-board charger also limits the power, so we check it before sizing.

In either case the Portuguese wiring rules ask for a dedicated circuit, for the vehicle only, with its own overcurrent protection and its own 30 mA residual-current protection. The residual-current device must be at least type A; for charging stations with a Type 2 connection, DGEG's technical guide also asks for detection of DC fault currents, by a type B device or by an associated detector. It is a point to check in any quotation.

The charger adds to the rest of the house. A single-phase wallbox at 32 A draws 7.4 kW: on its own it exceeds a contracted power (potência contratada) of 6.9 kVA. There are three answers, often combined: limit the charging current to a value the installation can carry; raise the contracted power, which above 10.35 kVA is only possible on three-phase; or install load management. A higher contracted power is paid for on every bill, whether you use it or not.

Load management, also called load balancing (in Portuguese, balanceamento de carga or controlo dinâmico de potência), continuously measures the total consumption of the home and adjusts the charger's current so that the sum stays under the set limit. When the oven comes on, the car charges more slowly; when it goes off, charging picks up again. This is what allows charging without raising the contracted power, when the home's consumption leaves headroom.

In buildings with several charging points, DGEG's technical guide provides for a load control system that shares out the available power.

The electric mobility regime (Decreto-Lei 93/2025, article 23) allows any unit owner to install, at their own expense, a charging point in the parking area of an existing building. DGEG's frequently asked questions (in Portuguese) clarify that the same applies to tenants and legal occupiers. Where the installation is in, or passes through, a common part of the building, the law requires prior written notice to the condominium administration, at least 30 days in advance. The administration may object only in the cases the law lists, for example if the building already has, or installs within 90 days, a shared charging point that meets the same needs, or if the installation is shown to put people or property at risk.

On the technical side, the question is where the energy comes from. DGEG's technical guide allows three sources: the main switchboard of your own flat, the building's riser board with a separate meter, or the common services board, an option the guide recommends only when the others are not feasible. The notice to the condominium is yours to send. We prepare the technical part: where the supply comes from, where the cables run, what protection is fitted.

• The make and model of the vehicle, or of the one you plan to buy.
• Photographs of the switchboard and of the parking space, and the approximate distance between the two.
• The contracted power, which is on your electricity bill.
• In a condominium: whether the space is a closed box, a marked space or a common part for your exclusive use, and where the building's switchboards are.

As a rule, we begin by assessing the existing installation, from photographs or on site. A proposal follows, with the equipment identified, the cable route and the changes to the switchboard.

At the end you have a dedicated, labelled circuit in the switchboard, a charger tested and set to the agreed current, and the execution document: the declaration of conformity of execution or the execution responsibility statement (termo de responsabilidade pela execução). Services are delivered by technicians accredited by DGEG.