Extremely low-frequency (ELF) fields are defined as those having frequencies to 3 kHz. At these frequencies, the wavelengths in the air are very long (6000 km at 50 Hz and 5000 km at 60 Hz). Electric and magnetic fields in this range are independent of one another and are measured separately.
Low frequency fields
ELF fields are emitted by most of the products in the home and in the workplace as well, such as copiers, power lines, wiring, transformers, household appliances, electric trains, electric blankets, electric waterbed heaters, hairdryers, electric shavers, television sets, computers, stereo systems, air conditioners, fluorescent lights, refrigerators, blenders, portable heaters, clothes washers and dryers, coffee makers, vacuum cleaners, toasters, computers, fax machines, copy machines, fluorescent lights, printers, scanner and other appliances.
ELFs are unsuitable for telecommunications because of the extremely severe bandwidth limitation and the difficulties of generating energy at these levels of frequency from any reasonably sized antenna. An individual is exposed to ELF electric and magnetic fields from many sources, here are only a few of them explained.
Transmission lines generate both strong electric and magnetic fields. Distribution lines generate weak electric fields but can generate strong magnetic fields, depending on the number of houses they supply. The strongest fields are normally encountered beneath high-voltage transmission lines; however, fields depend on the current flowing. The strength of magnetic fields from a power line depends on the power line’s height. The strength of magnetic fields from power lines depends also on the way the wires are distanced from each other. The higher the current the more apart the wires are spaced.
A significant percentage of the high-v01tage network worldwide is underground, mainly in urban areas or areas where there is a visual objection to the usage of overhead power lines, or where it is not convenient to use these lines. Unless they are buried very deeply, they may lead to higher fields. Ground-level magnetic fields from cables fall much more rapidly with distance than those from the corresponding overhead lines, but can actually be higher at small distances from the cables. Occasionally, burying electric power lines reduce fields, but this is not necessarily the case, as magnetic fields travel through mud, sand, rocks, and cement. Unless the underground cables are configured to reduce fields, simply hiding the cables out of sight may create a false sense of safety.
They are often located very close to residences and schools; therefore, substations are considered potential sources of electric and magnetic fields.I have seen a school build few meters apart from the substation.
Home electrical wiring produces electric fields from the voltage and magnetic fields from the current. Usually, magnetic fields in homes far away from power lines and substations are very low. If the home wiring is not grounded, there might be substantial magnetic fields all over the house. It is necessary to ground the wiring.
Commercial and Industrial Buildings
People working or visiting commercial buildings are exposed to low-frequency electromagnetic fields.
During driving a car, we are exposed to low-frequency electromagnetic fields like the power line, electric wiring inside the car, especially exposed are people who drive electric cars. Especially people driving with trains are exposed to electro magnetic fields.
Mains-powered appliances produce magnetic fields, whenever they draw current. Many workers receive more exposure at work than at home, despite less time spent there. Fields in the workplace tend to be higher than in the home, partly because of the greater concentration of appliances. Electrical devices such as photocopiers are common high-intensity sources and can emit high magnetic fields when in standby and double than that when making copies.
Monitors And TVs (CRT non LCD displays)
Especially old CRT monitors and TVs (non LCD) are especially dangerous for our health. They emit dangerous and strong fields of electromagnetic fields. I call them poisonous little electric boxes.
Read more about CRT and why you should throw them away immediately in another article on my site.