House electrical installation at the structural phase: stages, materials and cost
A house electrical installation at the structural phase (“la roșu”) comprises all the buried circuits (conduits, boxes, cables) fitted after the structure has been cast, but before plastering and the floor screed. This is the ideal moment to intervene: the walls are clear, the routes are easy to cut, and the cost is minimal compared with an installation fitted after the finishes. For a single-storey house of 80-120 sqm, 8-12 circuits are typically used, and the earthing electrode (priză de pământ) starts from 900 lei. Note: the interior installation is distinct from the electrical connection (bransament) to the grid (single-phase from 1,800 lei, three-phase from 2,900 lei), which is carried out separately, through Retele Electrice Romania S.A.
What “structural phase” means and why this stage matters
A building at the “structural phase” (“la roșu”) has its load-bearing structure completed (foundation, walls, floor slabs, roof), but no finishes. At this stage the buried electrical installation is fitted, because:
- the routes are cut directly into the masonry or fixed onto AAC blocks/brick without damaging the plaster;
- the conduits and boxes remain embedded in the wall, under the plaster;
- you can easily coordinate the electrical work with the plumbing and heating installations;
- you avoid costly chasing-out later on.
Mistakes made now (undersized circuits, badly positioned boxes, missing earthing) are very hard to fix once the finishes are in place. That is why the structural-phase installation must be carried out to a clear design and by an experienced team. See our electrical installations service.
The stages of the structural-phase electrical installation
1. The design and the circuit diagram
Before anything else, the number of circuits, the installed power and the consumer unit diagram are established. A good design separates the circuits by category:
- lighting circuits (usually 10 A);
- general socket circuits (16 A);
- dedicated circuits for large appliances: heating boiler, washing machine, oven, hob, water heater, air conditioning;
- a circuit for the earthing electrode (priză de pământ) and the equipotential bonding links.
For an ordinary house this comes to 8-12 circuits on average. If the supply is to be three-phase (400V), you balance the appliances across the three phases right from the design stage.
2. Routing the circuits on the walls
The positions for the consumer unit, sockets, switches, wall lights and ceiling lights are marked on the walls, along with the vertical and horizontal routes. The basic rule: routes run vertically and horizontally, never diagonally, so that you can later locate the cables without nasty surprises when drilling into the wall.
3. Chasing and fitting the boxes and conduits
The channels (chases) are cut along the routes and the recesses for the boxes are dug out. Then the following are fitted:
- the mounting boxes (for sockets and switches);
- the junction boxes (branch boxes);
- the protective conduits (corrugated/IPEY) through which the cables will be pulled.
The conduits allow cables to be replaced in the future without breaking open the walls, a major advantage.
4. Pulling the cables
The conductors, sized for each circuit, are pulled through the conduits. Indicatively:
- lighting: 1.5 sqmm;
- sockets: 2.5 sqmm;
- dedicated high-power circuits (hob, oven, water heater): 4-6 sqmm;
- the feeder to the consumer unit: sized according to the total power.
The cables are labelled at the ends and slack is left at the boxes and at the consumer unit for the subsequent connection.
5. The earthing electrode and the testing
The earthing electrode (priză de pământ) is installed (buried electrodes + earthing strip) along with the equipotential bonding links to the metal installations. At the end, measurements are taken: the earthing electrode resistance, the continuity of the protective conductors and the insulation resistance, recorded in PRAM test reports (from 250 lei). Details on the earthing electrode page.
Materials needed for the structural-phase installation
| Material | Role | Notes |
|---|---|---|
| Protective conduit (corrugated/IPEY) | Protects the cables in the wall | Allows later replacement |
| Mounting boxes | Fitting sockets and switches | Embedded in the masonry |
| Junction boxes | Branching the circuits | Access for inspections |
| 1.5 sqmm cable | Lighting circuits | Copper, insulated |
| 2.5 sqmm cable | Socket circuits | Copper, insulated |
| 4-6 sqmm cable | Dedicated power circuits | Hob, oven, water heater |
| Protective conductor (PE) | Earthing of the appliances | Yellow-green |
| Electrodes + OL-Zn earthing strip | Earthing electrode | Buried in the ground |
| Clips, plaster filler, consumer-unit brackets | Fixing and finishing | Preparation for the consumer unit |
The consumer unit, the miniature circuit breakers, the residual current devices (RCDs) and the wiring accessories (sockets, switches) are usually fitted during the finishing phase, but their sizing is decided at the design stage.
How much a house electrical installation at the structural phase costs
The cost depends on the floor area, the number of circuits, the type of supply (single-phase or three-phase) and the complexity of the routes. Below are indicative SUN WATT SRL prices. The final price is confirmed after the design has been assessed and, for the grid connection (racordare), through the ATR (Technical Connection Approval).
| Work | Indicative price |
|---|---|
| Single-phase connection (~11 kW) | from 1,800 lei |
| Three-phase connection (400V) | from 2,900 lei |
| Underground connection | from 3,500 lei |
| Temporary site connection | from 2,200 lei |
| Dossier + connection design | from 900 lei |
| ATR assistance | from 350 lei |
| DIU (Utilisation Installation Dossier) | from 1,200 lei |
| Power upgrade (spor de putere) | from 350 lei |
| Earthing electrode | from 900 lei |
| PRAM tests (reports) | from 250 lei |
Important: the table above covers the electrical connection (bransament) and the associated grid-connection works. The structural-phase interior installation (chasing, boxes, conduits, cables) is quantified separately, according to the number of circuits and consumption points. For a quick estimate, use the connection cost calculator or check the prices page.
The electrical connection vs. the interior installation: two distinct jobs
Many people confuse the two. In short:
- The electrical connection (bransament) brings power from the Retele Electrice Romania S.A. grid up to the connection cabinet/consumer unit of the house. It involves the ATR, a connection design and execution by an ANRE-certified firm.
- The structural-phase interior installation distributes power inside the house, across circuits, up to the sockets, light fittings and appliances.
For the interior installation to be legally energised, you also need the DIU (Utilisation Installation Dossier), from 1,200 lei. SUN WATT SRL, an ANRE-certified firm (execution + design), carries out both components and issues the DIU nationwide.
Why work with an ANRE-certified firm
For any work relating to grid connection and energisation, ANRE certification is mandatory. A certified firm:
- draws up the design in accordance with the regulations in force;
- carries out the connection and the installation in compliance with the technical requirements;
- issues the PRAM test reports and the documentation for the DIU;
- represents you in dealings with the distribution operator.
SUN WATT SRL covers Bucharest, Ilfov and Giurgiu for the execution and design of electrical connections, with a nationwide DIU.
Conclusion
The structural-phase electrical installation is the moment when you put the “brain” of the house in its place: clean routes, correctly sized circuits and a functioning earthing electrode. By following the 5 stages and using quality materials, you avoid costly problems after the finishes. For the design, connection execution and DIU, contact us on 0733 097 440 or request an estimate via the connection cost calculator.