Fields produced by overhead lines and underground cables

See also general explanations of the fields from overhead and underground power lines, more detail on the factors affecting the field, and details on the power laws describing how the field falls with distance.

To find out the field produced by a particular voltage line, click on the relevant cell in this table.

Fields produced by specific voltage lines

All these graphs show the actual field values. Graphs presented as percentages of the maximum field can be misleading. More on this. These calculations assume the currents within each circuit are balanced, which makes little difference to the higher fields at closer distances but can affect the smaller fields at larger distances. More on this.

	Overhead Lines			Underground Cables
400 kV		overhead magnetic field	overhead electric field	underground magnetic field
275 kV		overhead magnetic field	overhead electric field	underground magnetic field
132 kV		overhead magnetic field	overhead electric field	underground magnetic field
66 kV		overhead magnetic field	overhead electric field	underground magnetic field
33 kV		overhead magnetic field	overhead electric field	underground magnetic field
11 kV		overhead magnetic field	overhead electric field	underground magnetic field
400 V		overhead magnetic field	overhead electric field	underground magnetic field

Comparison of fields at different voltages

To compare the fields produced by different voltages, click on the relevant cell in this table

Distances for various fields

View the distance for the field to fall to various values.

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