Switching from Single-Phase to Three-Phase in Bucharest, Ilfov and Giurgiu

Switching from single-phase to three-phase becomes necessary when the electricity demand of a home or workshop exceeds what a 230V single-phase connection can support. Three-phase power (400V) provides greater capacity, distributed evenly across three phases, which is essential for heat pumps, EV charging stations, machine tools, welding equipment or small industrial machinery. From an administrative standpoint, this change is not simply a modification at the consumer unit: it means a new ATR (Technical Connection Approval) from the distribution operator and, in most cases, rebuilding the connection from the pole all the way to the distribution board.

SUN WATT SRL is an ANRE-certified firm for both the execution and design of electrical installations, and handles the entire process on a turnkey basis: from submitting the power-increase request and the file to Retele Electrice Romania, through to carrying out the three-phase connection, preparing the DIU (Utilization Installation Dossier) and energising the supply. You do not chase paperwork or queue at counters, we take care of all the bureaucracy.

When you need it

You need to switch to three-phase when your current approved power is no longer sufficient, or when you want to install equipment that runs on three phases. Typical situations include: installing a heat pump to heat your home, fitting a fast EV charging station (three-phase wallbox), setting up a workshop with machine tools, professional power tools or a welding machine, or extending a home or commercial space with several high-power appliances running at the same time. Three-phase is also recommended when single-phase fuses keep tripping as large appliances start up, or when motors and compressors require a starting current that a single phase cannot sustain reliably. If you are unsure whether you really need three-phase, or whether a simple power increase on single-phase would be enough, we will advise you free of charge, based on your actual consumption.

How it works — step by step

1. Assessment and power-increase request. We assess your consumption and the power you need free of charge, then prepare the connection modification request (power increase and switch to three-phase) together with the required documents. We submit the file to the operator Retele Electrice Romania (formerly E-Distributie / Enel).
2. Obtaining the new ATR (Technical Connection Approval). The operator reviews the request and issues a new ATR (Technical Connection Approval), which sets out the technical conditions of the three-phase connection and the connection fee. This is the stage that fixes the operator's final price. We follow up on the file and keep you informed until the approval is issued.
3. Connection contract and design. After signing the connection contract and paying the fee to the operator, we draw up the execution design for the three-phase connection, in line with the conditions set out in the ATR. All documentation is produced by a firm certified by ANRE for design work.
4. Execution of the three-phase connection. We install the three-phase connection from the pole / network to the connection cabinet and the distribution board, replace the conductors and protections for three phases (400V), and prepare the installation for the three-phase meter. The work itself is usually completed within a few days of the approvals.
5. DIU dossier, meter and energisation. We prepare the DIU (Utilization Installation Dossier) through an ANRE-certified electrician, which is required for fitting the three-phase meter. The operator installs the meter, the supply contract is concluded, and your three-phase connection is energised and ready to use.

Required documents

• Identity document of the account holder (ID card)
• Proof of ownership of the property (up-to-date land registry extract)
• Site plan and location plan
• Urban planning certificate (if required by the works or for new builds)
• Connection modification / power-increase request (we prepare this for you)
• Details of the current connection and contract (existing approved power, consumption point code)

Why bransam.ro

• Certified by ANRE for both execution and design, we work legally, with complete and compliant documentation.
• Turnkey service: we handle everything, from the file and the relationship with the operator Retele Electrice Romania through to energisation.
• No time wasted at counters, we manage the power-increase request, the ATR, the connection contract and the DIU on your behalf.
• Honest advice: we tell you whether you genuinely need three-phase or whether a power increase on single-phase would be enough.
• Correct execution of the switch to 400V, with protections and balancing across the three phases, for the safe operation of high-power equipment.
• Local coverage in Bucharest, Ilfov and Giurgiu, plus DIU dossiers nationwide, with a transparent quote within 24 hours.

How long it takes

As a rough guide, the entire process takes between 4 and 12 weeks, from submitting the file to energisation. Obtaining the new ATR from the operator usually takes a few weeks, while the execution of the three-phase connection itself can be done within a few days of the approvals. Timescales depend on the operator and the complexity of the works.

Indicative price