Induction hob

Induction cookers operate on the following basic physical principle: rapidly changing magnetic fields induce electric eddy currents in electrically conducting objects. These currents heat the cookware and indirectly its content. Alternating currents with a frequency of approximately 20 to 100 kilohertz flow in the cooker through one or several coils and create the necessary magnetic fields. Saucepans must be produced from suitable material in order to concentrate the fields within the cookware and thus improve heat generation.

Induction hob

As soon as the cookware is taken off the hob, the energy supply to the coil within the appliance stops and the magnetic field disappears.

So-called flex and full-surface induction hobs have several induction coils installed side by side that can be supplied with power independently of one another. The appliances detect which coils are covered by a saucepan either completely or to a defined minimum extent. If coils in an area are not covered, they remain deactivated and do not emit magnetic fields. The more individual coils are installed in an area, the better the emission of magnetic fields can be adapted – and limited – to a saucepan’s cross-sectional area. However, the complexity of the appliances increases with the number of coils, so this number is limited. The number of coils installed in an appliance is usually not stated in the product information.

As long as the instructions in the operating manual are followed only low magnetic stray fields can be observed in the vicinity of the cooker which decrease with increasing distance.

Higher magnetic fields may occur in case of inappropriate use

If inappropriate saucepans or frying pans are used higher stray fields may occur. Inappropriate is cookware

• produced of unsuitable material,
• with an uneven bottom,
• of improper size for the hob.

Higher fields can also occur if an appropriate saucepan is placed on the hob in such a way that the power supply of the coil is on the verge of being switched off.

At common distances to the hobs the appliances usually comply with the reference value of 27 µT for the magnetic flux density developed for the relevant frequency range by the International Commission on Non-Ionizing Radiation Protection (ICNIRP Guidelines 1 Hz – 100 kHz, 2010). In that case no health effects are expected. Under unfavourable conditions (inappropriate saucepan, not in the centre of the hob) the reference value can be reached close to the appliances. Due to the limited coupling of the fields with the body no health effects are expected but cannot be excluded if the reference values are reached.

Recommendations

Operating and safety instructions in the operating manual should be followed. Exposure to the magnetic fields of the induction hobs can be kept low if

• cookware of a fitting size made from appropriate material is used,
• the cookware covers the active cooking zones completely,
• a distance of five to ten centimetres to the front edge of the cooker or an active cooking zone is kept.

Please pay particular attention to the manufacturer's installation instructions for mobile devices. Some devices must not be operated on metallic surfaces as these could heat up due to magnetic stray fields.

Advice for people with active body aids

Patients with active body aids (as e.g. pacemakers) are recommended to ask their doctor if their implant is likely to be influenced by electric or magnetic fields of household appliances.

Note for pregnant women

The above recommendations also apply to pregnant women. Additional measures are not necessary.