Connecting a hob is a task that requires not only electrical knowledge, but also the correct choice of materials. An incorrect cable selection can lead to overheating, short circuit or even fire. This is especially true for modern induction and glass-ceramic panels, which consume up to 7-10 kW power.
In this article we will look at what cable is needed for a hob, depending on its type, power and connection method (single-phase, three-phase). You will learn how to calculate wire cross section, which brands of cable are best suited, and what mistakes are most often made during installation. We will also provide step-by-step instructions for connecting and answer the most frequently asked questions.
If you are not confident in your abilities, it is better to entrust the work to a professional electrician. But even in this case, knowledge of the theory will help control the process and avoid deception on the part of the performers.
1. Why does the hob need a separate cable?
The hob is one of the most energy-intensive household appliances. Unlike a refrigerator or microwave, it consumes from 3 to 10 kW depending on the model. For example, induction hob Bosch PUE611BF1E has maximum power 7.4 kW, and Electrolux EHH56240FK - whole 9.2 kW.
A standard 16 A household outlet is rated for a maximum of 3.5 kW (220V × 16A). If you connect a powerful panel through a regular outlet, the wires will start to heat up, and the machine will constantly knock out. Therefore, the hob requires:
- 🔌 Separate line from an electrical panel with its own automatic machine;
- 📏 Cable with sufficient cross-section (usually 4 or 6 mm²);
- ⚡ Special socket (if the connection is not direct).
If your house has old aluminum wiring, it absolutely cannot be used on a hob - copper cable only. Aluminum oxidizes over time, loses conductivity and can cause a fire.
2. How to calculate cable cross-section by power
The cable cross-section depends on panel power and connection type (single-phase or three-phase). For calculation use the formula:
I = P / U, where:
- I — current strength (A);
- P — panel power (W);
- U — voltage (220V for single-phase, 380V for three-phase).
Example: if your panel Samsung NZ64K37471K has power 7.3 kW (7300 W) and connects to a single-phase network (220V), then:
7300 W / 220V ≈ 33.2 A
Next, use the table to select the cable cross-section. For copper at current 33 A suitable wire 4 mm² (maximum permissible current - 38 A). If the power is higher (e.g. 9 kW), a cable will be required 6 mm².
| Panel power (kW) | Current (A, 220V) | Cable cross-section (mm², copper) | Machine rating (A) |
|---|---|---|---|
| Up to 3.5 | Up to 16 | 2,5 | 16 |
| 3,5–5,5 | 16–25 | 4 | 25 |
| 5,5–7,5 | 25–34 | 6 | 32 |
| 7,5–10 | 34–45 | 10 | 40 |
⚠️ Attention: If the hob is connected to a three-phase network (380V), the current decreases by √3 times (by about 40%). For example, for 7.3 kW: 7300 / 380 ≈ 19.2 A. In this case, the cable will suffice 2.5 mm².
3. Which brand of cable to choose
Only suitable for connecting the hob copper multicore cables with non-combustible insulation. Best options:
- 🔥 VVGng-LS - the most popular choice. Non-flammable, with low smoke and gas emissions. Suitable for hidden and open wiring;
- 🛡️ NYM — imported analogue of VVG, with an additional rubber shell. Convenient for installation, but more expensive;
- ⚡ PVS — flexible wire, suitable for connecting the panel to an outlet (but not for fixed wiring!).
For three-phase connection use 5-core cable (3 phases + zero + ground), for single-phase - 3-wire (phase + zero + ground). Core colors are standardized:
- 🟡 Yellow-green - earth (PE);
- 🔵 Blue — zero (N);
- 🟤 Brown/black/gray — phase (L).
⚠️ Attention: Cable SHVVP or PUNP use for hob it's impossible - they are not designed for such loads and can melt.
If the cable length from the panel to the panel exceeds 20 meters, increase the cross-section by one step (for example, instead of 4 mm², take 6 mm²) to avoid voltage loss.
4. Single-phase vs three-phase connection
The connection method depends on the capabilities of your wiring and the panel itself:
- 🔌 Single phase (220V) - standard for apartments. A 3-core cable is used. All phase terminals on the panel are connected by a jumper;
- ⚡ Three-phase (380V) - common in private homes. A 5-wire cable is required. The phases are distributed over individual terminals (usually L1, L2, L3).
As a rule, hobs support both options. On the back of the device there is a connection diagram indicating which jumpers to install for a single-phase or three-phase network.
Panel example Gorenje IT635ORA:
- For 220V: connect the terminals
L1, L2, L3jumper and connect to the phase; - For 380V: connect phases A, B, C to
L1, L2, L3accordingly.
What happens if you confuse phase and zero?
If you confuse phase and zero when connecting the hob, the device may not work correctly (for example, it may not heat at full power or may turn off). In the worst case, this will damage the panel electronics. However, modern models usually have protection against incorrect phasing.
5. Step-by-step instructions for connection
Before starting work be sure to turn off the electricity on the shield! To connect you will need:
- 🔧 Cable of the required section;
- 🔌 Socket and plug (if not direct installation);
- 🔨 Automatic switch;
- 📏 Terminal blocks or sleeves for crimping;
- 🛠️ Indicator screwdriver, stripper, pliers.
☑️ Preparing to connect the hob
Step 1: Connecting the cable to the panel
Remove the back cover of the panel (usually it is secured with latches or screws). Find the terminal block and connect the cable cores according to the diagram:
- Yellow-green - to terminal
PE(ground); - Blue - to
N(zero); - Brown/black - k
L(phase).
Step 2. Installation of the machine
Install in the electrical panel differential machine (or a combination of RCD + automatic) with a rating one step higher than the rated current. For example, if the current is 33 A, the machine should be on 40 A.
Step 3: Connect to the network
If you use an outlet, it must be power (for example, Legrand 67285 at 32 A). For direct connection, the cable is inserted directly into the panel terminal block.
⚠️ Attention: If the cooktop and oven are connected to the same line, the total power may exceed the capacity of the cable. In this case you need separate cable for oven or thicker wire (for example, 6 mm² instead of 4 mm²).
6. Common mistakes and how to avoid them
Even experienced craftsmen sometimes make mistakes when connecting the hob. Here are the most common:
- 🔥 Using aluminum cable — leads to oxidation and overheating;
- 🔌 Connection via a regular outlet - cannot withstand the load;
- ⚡ Lack of grounding - life-threatening;
- 📏 Wrong cable section — leads to insulation melting;
- 🛠️ Poor contact in the terminal block - may cause sparking.
Another typical problem is using twists instead of terminal blocks. Over time, the twist weakens, the contact deteriorates, and the joint begins to heat up. Always use terminal blocks (for example, Wago 222) or sleeves with crimp.
If after connection the panel is unstable (turns off on its own, does not heat at full power), check:
- Mains voltage (must be 220–230V for single-phase connection);
- Quality of contacts in the terminal block;
- Correspondence of the cable cross-section to the declared power.
The most common cause of breakdowns of hobs is incorrect cable cross-section. Even if the panel is working, the thin wire will heat up, which will eventually lead to damage to the insulation and a short circuit.
7. FAQ: Answers to frequently asked questions
Is it possible to connect the hob without grounding?
No, this is extremely dangerous. Without grounding, if the insulation breaks down, phase voltage may appear on the panel body, which will lead to electric shock. If your home does not have grounding, you need to organize zeroing (but this is a temporary solution - it is better to make a full-fledged ground loop).
Which machine should I put on a 7 kW hob?
For a single-phase connection (220V), you need an automatic 32 A (cable cross-section 6 mm²). If the connection is three-phase (380V), the machine will be enough for 16–20 A (section 2.5 mm²). It is also recommended to install RCD 30 mA for protection against current leakage.
Can I use a 2.5 mm² cable for a 5.5 kW panel?
Technically possible, but not recommended. The 2.5 mm² cable can withstand up to 25 A (5.5 kW), but operates at the limit of its capabilities. It's better to take 4 mm² - this will provide a power reserve and reduce the heating of the wire.
What to do if the cable from the panel is too short?
Use terminal block for cable extension. Twists or "nuts" are not suitable - they do not provide reliable contact. You can also replace the cable from the shield to the panel with a longer one (but this will require chiselling of the walls).
Do I need a separate outlet for the hob?
Not necessarily. You can connect the panel directly through the terminal block (this is even more reliable, as it eliminates unnecessary connections). An outlet is only needed if you want to be able to quickly disconnect the panel (for example, for repairs).