ELECTRIC FIELDS AND NUISANCE SHOCKS
Landowners should be aware of the following guidelines and issues.
• AEP must review and approve in writing changes in ground
elevation in a right-of-way. Placement of fill dirt in the right-of-way
reduces conductor-to-ground clearance. This is not allowed
without prior AEP approval. (See contact information below.)
An unapproved fill could require AEP to raise its electric lines
at the landowner’s expense.
• Roads or lanes generally are permitted to cross rights-of-way.
While such crossing should be located close to a transmission
structure, the actual location must be reviewed and approved
by AEP. Proximity to a tower provides maximum vertical
clearance between energized conductors and vehicles.
• No dirt or spoil shall be stored or deposited – even temporarily –
on a right-of-way for any reason.
• Any excavation in the right-of-way must have a minimum
40-foot-radius buffer of undisturbed soil around all transmission
structures, including guy wires and anchors, for 345 kV and above
lines. A 30-foot-radius buffer is required for 34 -161 kV lines.
AEP must approve any excavation that affects its access to
a transmission structure.
• AEP must approve all electric, gas, telephone, cable TV,
water, sewer and other lines in the right-of-way. These lines must
be placed at least 40 feet from all structures, and overhead
clearances must be maintained.
• No pond, lake or other water detention area is allowed to cover
the entire width of an electric transmission line right-of-way.
A minimum corridor width of 30 feet must be available for large
utility vehicles to drive the length of the right-of-way without
restriction for maintenance purposes.
An electric field or e-field contains invisible lines of force produced by
electric voltage. An e-field surrounds any wire or conductor that has
voltage placed upon it. When energized, power lines, electrical
wiring, appliances, TV sets, hair dryers, computers and other
electrical devices produce e-fields. An e-field is a natural force that
cannot be eliminated or confined. Its strength varies with distance
from the conductor. E-field strength is stronger near its source and
decreases with distance from the conductor.
E-fields cause induced-voltage nuisance shocks when a person
touches an ungrounded metal object or other conductor, such
as a vehicle parked on or slightly off the right-of-way. A nuisance
shock will not harm the recipient but could be startling.
The prospect of such shocks is influenced by many factors, including:
• line voltage
• conductor ground clearance (vertical distance) and horizontal distance
• type of material (conducting or non-conducting)
• type of soil (resistance to electrical charge)
• location and size of vehicle or object
• atmospheric conditions and personal physiology
• insulating capability of one’s shoes
The location of a vehicle or object within a right-of-way is the primary
factor in nuisance shocks. Typically, nuisance shocks occur with
vehicles parked in or next to the right-of-way of a 345 kV (or larger) line.
Larger conductive objects (tall or long trucks, for example) are more
likely to build up a greater charge. Thus, they may deliver a potentially
annoying shock when a person’s body provides a path to ground for
electric current. In some cases backyard metallic objects such as
swings, portable grills and parked lawnmowers can deliver
shocks if located in or close to an extra high voltage line’s right-of-way.
Contact with an ungrounded metal fence can also deliver a shock.
Someone cleaning gutters on a structure near the edge of a high
voltage line can get a shock.
Predicting the likelihood of nuisance shocks is impossible. As
mentioned, e-field strength is determined by distance from the source.
Institute of Electrical and Electronics Engineers (IEEE) guidelines and
calculated e-field magnitudes were used to create the table below –
Likelihood of Shock Occurring with Vehicles Parked in the Right-of-Way.
This table contains general information and is intended for general public
education about e-fields and the potential for nuisance shocks. It was
prepared to show the types transmission lines with vehicles parked in
the right-of-way that could produce nuisance shocks.
• Light standards or poles in the right-of-way must be approved in
advance by AEP to maintain proper clearance.
• Erosion problems from landowner actions are the landowner’s
responsibility. If a problem threatens the integrity of AEP’s
power lines, the landowner should notify AEP immediately
and take corrective action.
• No temporary or permanent structures, buildings, in-ground or
above ground pools, playground equipment or other fixed im
provements should be erected in the right-of-way.
• Ingress and egress (right of passage in and out of property) to
AEP lines are critical. Therefore, any fences along the entire
width of a right-of-way should have a 14-foot-wide gate with an
AEP lock in the locking chain.
• All fences with metal components should be grounded to prevent
nuisance shocks.
• Row crops – corn, wheat, cotton, soybeans, for example – are
permitted in rural right-of-way, but not tree farms. Keep in mind
that line trucks traveling along a right-of-way can damage crops.
Compensation terms for crop damage from maintenance work are
covered in the easement.
• In urban areas, many easements are used for lawns, gardens and
recreational areas. These are acceptable as long as they do not
endanger the safe operation of the line. Parking lots are usually
acceptable under lines up to 161 kV. Higher voltage lines could
produce induced voltage shocks that may be uncomfortable to
some users. Landowners should contact AEP regarding
parking vehicles under or near 230 kV to 765 kV lines. Planting
trees, especially taller-growing and/or nut-bearing varieties, is not
permitted in an easement. Low-growing fruit trees or shrubs are
generally acceptable. Contact AEP at the number listed
below with questions. AEP reserves the right to trim or
remove trees at its discretion.