Underground and EMF
The electric fields from underground cables are shielded by the wire's insulation and the surrounding ground, but the magnetic fields are not. Based on the example of an underground installation (see illustration at the bottom this page), the magnetic field would be higher immediately above the buried transmission line, than below the proposed overheadline. However, the magnetic fields from an underground line drop off more quickly as you move away from the buried cable. Magnetic fields drop off quicker when the buried cables are placed closer together which results in the magnetic fields diminishing more quickly with distance, compared to an overhead line where the cables are farther apart. Other factors such as how the lines are arranged, and number of circuits in the line also influence the magnetic field levels.
For more information on Underground and EMF as well as EMF profiles, please click here to download the Underground Option brochure.
Underground Transmission Lines | Stakeholder-requested Option