Many electrical devices cause interference in their environment due to electromagnetic feedback generated during operation. This interference can spread in a conducted or radiated fashion – through electromagnetic waves – emanating from the devices. In both cases, this is referred to as electromagnetic interference emissions.
To facilitate largely interference-free operation of devices located around the device in question, there are two possible course of action:
Limiting the interference emissions of the one device, and
increasing the resistance of surrounding devices, i.e. their immunity regarding the reception of interference.
Since all devices operated within an electrical installation are interrelated as emitters and receivers of interference in actual operation, proper operation for all participants can only be ensured by determining the permissible degree of interference emissions as well as a minimum resistance for each device. This is referred to as electromagnetic compatibility (EMC).
Luminaires are electrical components which are increasingly equipped with electronic components in this day and age. Generally, interference emission and resistance of electronic circuits greatly depend on circuit design. Layouts for electromagnetically compatible circuits therefore require a great deal of diligence to ensure reliably stable operation. In view of this, EMC aspects are highly important in modern, professional lighting.
Beyond EMC issues, the effects of electromagnetic fields on the human body are outlined by EU directive 2013/35/EU, which has been implemented e.g. through the German federal "Verordnung über elektromagnetische Felder - 26. BImSchV" ("Ordinance on Electromagnetic Fields").