Apartment Electrical Wiring: How to Plan a Rewire Without Mistakes
Volodymyr SydorenkoJuly 2, 2026
Everything about rewiring an apartment: signs of worn wiring, allocated capacity, cables and cross-sections, circuits, breakers, RCDs and surge protection, earthing, sockets, backup power during outages and accepting the work.
Apartment Electrical Wiring: How to Plan a Rewire Without Mistakes
Wiring is the foundation of an apartment's safety. Worn wiring is a common cause of house fires, and poorly designed wiring causes daily frustration: breakers trip, there aren't enough sockets, extension cords snake across the room. A modern apartment with an induction cooktop, water heater, air conditioners and power stations needs a completely different network from one designed 40 years ago. Here's how to plan and carry out a rewire properly.
When Wiring Needs Replacing
- Aluminum wiring. Typical of pre-1990s buildings. Aluminum oxidizes, becomes brittle and its connections overheat. Such wiring should be fully replaced with copper.
- Wiring older than 25–30 years. Insulation ages and cracks.
- Warning signs: hot sockets and switches, a burning smell, sparking, flickering lights, frequent breaker trips.
- No earthing — in older buildings sockets are often two-wire.
- A major renovation — the best moment to rewire, because later you'd have to break new finishes.
The fire hazard of faulty electrics is also highlighted by the US National Fire Protection Association (NFPA), which lists electrical failures among the leading causes of home fires.
Step 1. Allocated Capacity
Before designing the network, find out the capacity allocated to your apartment. In older buildings it's often 3–5 kW, in new builds 7–10 kW or more. This is in the contract with the distribution system operator or the building's technical conditions.
If you plan an induction cooktop, electric water heater, several air conditioners and a powerful battery charger, the capacity may not be enough. Increasing capacity is a connection procedure with the distribution system operator, governed by the Law on the Electricity Market and the rules of the regulator NEURC. It isn't always possible: the limit may be the building's supply. Ask the condominium association or manager.
Step 2. Design the Network
An electrical plan is part of the design project. It includes:
- the location of all sockets, switches and lights with heights;
- circuits with the load of each;
- a single-line diagram of the panel with breaker and RCD ratings;
- the cable cross-section for each circuit;
- the cable routes.
Plan sockets around the furniture layout: by the bed, desk and TV, in the kitchen above the worktop, in the hallway for the vacuum cleaner, on the balcony.
Step 3. Circuits
Divide the network into independent circuits:
- lighting — 1–3 circuits depending on area;
- sockets in living rooms — a separate circuit for every 1–2 rooms;
- kitchen sockets above the worktop;
- dedicated circuits for heavy loads: induction cooktop, oven, dishwasher and washing machine, water heater, air conditioners, underfloor heating;
- bathroom — a separate circuit with an RCD.
Dividing into circuits lets you switch off one line for repairs without cutting power to the whole apartment and choose the right protection.
Step 4. Cables and Cross-Sections
- Material — copper only.
- Type — fire-retardant, low-smoke cable.
- Number of cores — three-core (line, neutral, protective earth) for a single-phase network.
Typical cross-sections for copper cable:
- lighting — 1.5 mm² with a 10 A breaker;
- sockets — 2.5 mm² with a 16 A breaker;
- induction cooktop or electric stove — 4–6 mm² with a breaker matched to the appliance's power.
The exact values are determined by an electrician based on cable length and installation method.
Step 5. The Panel and Protection
A modern apartment panel contains:
- a main breaker;
- a surge protection device — protects appliances from voltage spikes;
- a voltage relay — disconnects the supply when voltage is too low or high, especially relevant on unstable networks and when power is restored;
- residual current devices (RCDs) or RCBOs with 30 mA on socket circuits and wet-room circuits — they protect against electric shock;
- circuit breakers for each circuit;
- neutral and earth busbars.
The panel should be labeled: which breakers control which circuits.
Step 6. Earthing
A protective earth conductor is an essential part of a modern network. In older buildings with two-wire systems there may be no earthing at all. The solution is determined by an electrician: running a protective conductor from the building's main panel (with the condominium association or manager) or another technically acceptable option. Never connect "earth" to heating or water pipes — it's dangerous.
Step 7. Installation Rules
- Run cables in walls only horizontally and vertically, never diagonally.
- Keep the required distances from corners, door and window openings and the ceiling.
- Use conduit or cable channels so cables can be replaced.
- Make connections in junction boxes with terminals or crimping, not twisting and electrical tape.
- Don't cut horizontal chases in load-bearing panels in panel buildings — it weakens the structure.
- Photograph the entire route with a tape measure before plastering.
Step 8. Backup Power During Outages
Power outages have changed how networks are designed. Options for independence:
- Power stations and power banks — simple solutions for lighting, the router and phones.
- An inverter with batteries — powers selected circuits (lighting, router, fridge, boiler) during an outage. Plan its connection in the design: create a "backup" group of circuits in the panel.
- A generator — for balconies and private houses; connected through a changeover switch that prevents feeding power into the external grid.
- Solar panels — for private houses. More in solar panels for home.
Place batteries according to the manufacturer's recommendations, in ventilated spots away from heat sources.
Step 9. Accepting the Work
- Check that sockets and switches match the design.
- Ask for an insulation resistance test report and protection device tests.
- Press the "Test" button on every RCD — it should trip.
- Check the panel labels.
- Get an as-built diagram and photos of hidden wiring.
How to choose an electrician and draft a contract is covered in how to choose a renovation contractor.
Sockets: How Many and Where
Typical needs:
- living room — 6–10 sockets, including by the TV;
- bedroom — two on each side of the bed, by the dressing table, for the air conditioner;
- kitchen — 4–6 above the worktop plus for built-in appliances;
- study — a block of sockets by the desk plus network sockets;
- hallway — for the vacuum cleaner and chargers;
- bathroom — protected sockets according to safety zones (see bathroom renovation).
It's better to plan more sockets than to rely on extension cords later.
Lighting: Scenes, Not Just a Chandelier
When rewiring, plan several layers of light for each room:
- general — ceiling lights or track systems;
- task — above the worktop, desk and mirror;
- accent — lighting for niches, pictures and shelves;
- night — soft lighting in the hallway and bathroom with a motion sensor.
Two-way and intermediate switches let you control hallway or bedroom lights from several points. For dimmers, check compatibility with LED bulbs. Lighting scenes are especially important in small apartments — more in small apartment design.
Smart Home
When rewiring, it's easy to lay the groundwork for "smart" solutions: smart switches (some need a neutral wire in the back box), leak sensors, control of lights and air conditioners, energy monitoring. Run network cable to key points — Wi-Fi doesn't always replace a wired connection.
Energy Efficiency
LED lighting, energy-efficient appliances and smart thermostats reduce consumption. The ENERGY STAR program notes that smart thermostats help save energy on heating and cooling. Lower consumption also means longer battery runtime during outages.
Common Mistakes
- Leaving part of the old aluminum wiring "because it works".
- Skimping on cable cross-section.
- One circuit for the whole apartment.
- No RCD.
- Twisted connections instead of terminals.
- No diagram or photos of hidden wiring.
- Connecting a generator without a changeover switch.
- Cheap no-name breakers and RCDs that don't trip when they should.
Frequently Asked Questions
How much does rewiring cost? It depends on the area, number of points and complexity of the panel. Labor and materials for a two-room apartment are a significant part of the renovation budget, but it's an investment in safety for decades.
Can I rewire without chasing walls? Partly — in cable channels, skirting or behind plasterboard. But a full rewire usually involves chasing.
Does rewiring need approval? The in-apartment network after the meter is your responsibility. Work on the supply, meter and capacity increases is agreed with the distribution system operator.
Can I do the electrics myself? Installation requires qualifications. Mistakes risk fire and electric shock, so hire a professional electrician.
How often should wiring be checked? Inspect the panel and sockets every few years, tighten connections and test RCDs with the "Test" button at least every six months. After a flood or fire, an electrician's check is a must.
What if I bought an apartment with old wiring and no renovation is planned? At least replace the panel with modern breakers and RCDs and check the condition of connections — this significantly improves safety.
Conclusion
Quality wiring means a design, copper cable of the right cross-section, separate circuits, a modern panel with RCDs and surge protection, earthing and well-planned backup power. Build all this in during a major renovation and the network will serve safely for decades. The general renovation sequence is described in our apartment renovation guide.
Sources
- Law of Ukraine on the Electricity Market.
- NEURC — connection rules and retail electricity market rules.
- NFPA: home fire safety.
- ENERGY STAR: smart thermostats.
- Civil Protection Code of Ukraine.