Substations and Transmission Lines
Characteristics of Electromagnetic Fields (EMFs)
Electricity generated by a power plant is delivered through transmission lines, transformers and substations to households. Power plants generate 50 Hz (Hertz) or 60 Hz extremely and they are delivered to the users via power transmission and distribution facilities.
Adverse Health Effects
When human body is exposed to an extremely low frequency electromagnetic field (ELF-EMF) of 50 Hz or 60 Hz generated by power transmission or distribution facilities or other utilities, electric field effects could originate. If the body is exposed to an electromagnetic field (EMF) that is hundreds of times stronger than in the common living environment, some important physiological functions, such as nerve, heart and muscle activities may be hampered. However, no EMF with such strength exists in the common living environment. Therefore EMFs generated by a transmission line or substation is thought to have no adverse health effects.
Warning: It is extremely dangerous for everyone to be in direct contact with wire or outlet: human body would act as a conductor and such contact might lead even to death.
Effects from Magnetic Fields
Some epidemiological studies claimed that the incidence of childhood leukaemia doubles in case of continuous exposure to magnetic fields of 0.4 microtesla (μT) or stronger. However, no biological mechanisms or evidence from animal studies have been found. Overall, the published evidence linking childhood leukaemia to magnetic field exposure is not powerful enough to demonstrate a causal relationship. The evidence for adverse effects on other diseases is said to be even subtler than the evidence of the effects on childhood leukaemia.
Effects from Electric Fields
Electric fields are thought to have no adverse effects on human health in the common living environment. The reason might be that the electric fields of lower or medium strength do not penetrate into the human body, while the magnetic fields do.
Regulations on Electric Fields
Japanese law stipulates that high voltage power lines shall be installed so that electric fields generated thereby are below 3 kilovolts per meter (kV/m). However, the objective of this regulation is not to protect against adverse health effects but to prevent an unpleasant feeling (electric shock) from electric fields when passing under high voltage power lines.
Regulations on Magnetic Fields
Japanese law stipulates that high voltage power lines and substation shall be installed so that magnetic fields generated thereby are below 200 microtesla (μT) .This value is based on ICNIRP guidelines (reference levels for general public at 50 Hz and 60 Hz).