Extremely low-frequency (ELF) fields are defined as those having frequencies up 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.

When I do Home EMF inspections I always measure first electric fields then magnetic fields. These two coexist and many times it happens that the values of electric fields are in a healthy range, but magnetic fields are in an unhealthy range based on our Swedish strict geo biological EMF standards, and vice versa.

Low-frequency fields are divided into:

• electric fields measured in volt per meter (V/m)
• magnetic fields measured in nanotesla (nT)

Electric and magnetic fields are produced by electricity which is a movement of electric current through the electric wire.

1. Electric fields are the direct result of voltage, which is the pressure of the electrons being pushed through the electric wire. When the voltage increases, the electric fields become stronger. ELectric fields are measured in volts per meter.
2. Magnetic fields on the other hand are the direct result of the current flowing through the wires, or electrical devices. When the current increases so do the magnetic fields. They are measured in microteslas, but I personally use nanoteslas because of the EMF meters that I use. 0.001 Microtesla [µT] is equal to 1 Nanotesla [nT]. I do all my measurements of magnetic fields in nanoteslas on our website and our youtube. 

An electric field is produced by voltage, which is the pressure used to push the electrons through the wire, much like water being pushed through a pipe. As the voltage increases, the electric field increases in strength. Electric fields are measured in volts per meter (V/m).

A magnetic field results from the flow of current through wires or electrical devices and increases in strength as the current increases. The strength of a magnetic field decreases rapidly with increasing distance from its source. Magnetic fields are measured in microteslas (μT, or millionths of a tesla).

Electric fields are emitted when the device is turned on or off, while the magnetic fields only exist when there is a current flowing through the device. That means when the device is turned on. A nice example is power lines, which emit magnetic fields constantly because there is current flowing through them all the time.

There is a big difference in shielding and EMF protection against electric and magnetic fields. Electric fields can be easily neutralized or shielded, even with grounded aluminum foil, walls, objects, aluminum mesh, emf paints that you can find in our EMF store, while magnetic fields are almost impossible to be stopped. Magnetic fields pass through our bodies, buildings, living things, and other materials. There is practically no shielding for them. So living near the power lines can be dangerous and we advise people to move because you can’t block magnetic fields at all.

Power Lines

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.

 

Underground Cables

A significant percentage of the high-voltage 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.

Substations

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 a few meters apart from the substation.

Home Wiring

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.

 

Transportation Sources

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 electromagnetic fields.

 

Electric Appliances

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 that when making copies. Other devices like shavers, hairdryers electric blankets, laptops, electric ovens are also the source of EMF fields.

Monitors And TVs (CRT non LCD displays)

Especially old CRT monitors and TVs (non LCD and LED or OLED) are especially dangerous for our health. They emit dangerous and strong fields of electromagnetic fields. I call them poisonous little electric boxes. But you can’t find them anymore, they were replaced by LED monitors which is great.