I want to figure out what cable to use for different circuits in my electrical system. I've heard that outlets require one cross-section, lighting another, and the stove a third. How do I make sure I get the calculation right?
The basics here are correct, but let me add from my experience: for outlets 2.5 sq.mm is indeed the standard, but lighting can often be run on 1.5, though if there are a lot of light fixtures in the room or a powerful chandelier, it's better not to skimp and go with 2.5 as well.
The main rule is to check the circuit breaker rating in the panel: if it's rated for 16A, the cable needs to handle exactly that current without overheating, so it's better to pick a cross-section with some margin.
For the stove, oven, and electric boiler you'll need a separate line rated for 4-6 sq.mm depending on the power - definitely no skimping there. If your apartment has old wiring and the panel is overloaded, it makes sense to call an electrician to figure out what can actually be safely connected.
When I was doing the electrical work in my house, I went by a simple rule: outlets usually run on 2.5 sq.mm (max 16A), lighting is fine with 1.5 sq.mm, and for heavy-duty appliances like an electric stove you need a separate circuit on 6 sq.mm or bigger depending on the power.
The main thing is to calculate the maximum current for each circuit and pick the right cable size from a table, otherwise you'll run into problems later, and make sure you install the correct circuit breakers for each cable.
When I was planning the electrical system in my house, I chose the cable not just based on power capacity, but also on the length of the run - the farther from the breaker panel, the greater the voltage drop, and sometimes I had to go with a larger cross-section than it initially seemed necessary.
Here's a tip: grab a floor plan of your apartment, mark the distances from the breaker panel to each group of outlets/light fixtures, and pick a cross-section with a little safety margin - it'll save you from flickering lights or overheating wires down the line a couple years later.
What current do you need for your outlets - 16 amps or more?
The basic rule is simple: you calculate based on the maximum current in the circuit, then pick the wire gauge accordingly. For regular outlets in a residential building, the standard is 2.5 sq.mm wire with a 16A breaker - this works for the vast majority of cases. For lighting, 1.5 sq.mm is actually enough (10A breaker). But for an electric stove, oven, or powerful heater, you need to calculate based on their actual power consumption - often that's 4-6 sq.mm depending on your kitchen equipment.
One thing I want to emphasize: wire gauge affects not just whether it can handle the current, but also voltage drop on longer runs. If you've got a long line from the panel to the far end of your hallway, sometimes it's worth going up a wire size even for modest current. This matters more on longer stretches - when the cable runs 5-6 meters from the main distribution box and beyond. But for a standard apartment, people usually don't worry about this and just use the same 2.5mm without overthinking it.
The main thing is don't skimp on wire gauge banking on the idea that you'll never have powerful appliances in your apartment. If you don't have much electronics now, tomorrow you might want an air conditioner or a second fridge. Better to go with a little safety margin than have to redo everything later.
The main thing is to calculate based on the maximum simultaneous load, not the breaker rating. I once connected a cooktop in my apartment and ran into an issue where my neighbor downstairs complained about the lights flickering whenever I turned on the oven along with the burners - it turned out the line was designed for less current than needed. I had to redo the cable with a larger cross-section.
From experience: for regular outlets 2.5 sq.mm is indeed enough, for lighting 1.5 is usually sufficient, but if the room is large with multiple chandeliers and fixtures, it's better not to risk it and go with 2.5. For high-power appliances (stove, boiler, air conditioner) you need to take their rated power, divide by voltage, and give yourself a safety margin - often 4-6 sq.mm or more is required. And yeah, it makes sense to account for the distance from the panel, like someone mentioned above - outlets farther away on a long run experience greater voltage drop.
The most reliable way is to calculate not by standard guidelines, but by the actual power of the appliances you'll be running at the same time. Take the sum of watts, divide it by the voltage (usually 220V) and you'll get the current in amps, then pick the wire gauge based on that.
The previous answers correctly named the typical values (2.5 mm² for outlets, 1.5 mm² for lighting), but they only work if you really don't plan to plug several powerful appliances into one outlet group at the same time. For example, if a microwave, water heater, and electric kettle are on the same circuit in one room, 2.5 might not be enough - I've checked this more than once when I redid the wiring in my own place.
The point about line length is also valid - voltage does drop over long runs, but in an apartment this is rarely critical. However, for an electric stove (if it's a real cooktop at 230V, not a portable hotplate), you definitely need a separate heavy-duty line from the panel, minimum 6 mm² or even 10 mm².
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