Type of Line | Right of Way | 15m/50ft | 30m/100ft | 61m/200ft | 91m/300ft |
115 kV | 1.0 kV/m
29.7 mG |
0.5 kV/m
6.5 mG |
0.07 kV/m
1.7 mG |
0.01 kV/m
0.4 mG |
0.003 kV/m
0.2 mG |
230 kV | 2.0 kV/m
57.5 mG |
1.5 kV/m
19.5 mG |
0.3 kV/m
7.1 mG |
0.05 kV/m
1.8 mG |
0.01 kV/m
0.8 mG |
500 kV | 7.0 kV/m
86.7 mG |
3.0 kV/m
(20m/65ft) 29.4 mG |
1.0 kV/m
12.6 mG |
0.3 kV/m
3.2 mG |
0.1 kV/m
1.4mG |
These are typical EMFs at 1m/3.3ft above ground for various distances from power lines in the Pacific Northwest. They are for general information. For information about a specific line, contact the utility that operates the line. Source: Bonneville Power Administration 1994.
Electric fields from power lines are relatively stable because line voltage doesn't change very much. Magnetic fields on most lines fluctuate greatly as current changes in response to changing loads. Magnetic fields must be described statistically in terms of averages, maximums, etc., The magnetic fields above are means calculated for 321 power lines for 1990 annual mean loads. During peak loads (about 1% of the time), magnetic fields are about twice as strong as the mean levels above.