Causes of Power Outages

Power outages can be caused by many circumstances. Storms, accompanied by heavy wind and lightning, are major causes of power outages. However, people and animals can also cause the power to go out.

Lightning

Lightning looks for the quickest path to the ground. It generally searches for the tallest object to serve as a conductor. Utility poles, wires, transformers and other electrical equipment are easy targets for lightning strikes, causing severe damage and loss of power. Lightning also frequently strikes trees causing tree limbs or even large trees to fall onto utility lines.

Wind

Wind may cause power lines to swing together resulting in a fault or short circuit that interrupts service. Strong wind can blow tree limbs or entire trees into power lines causing them to fall to the ground. Severe winds can even break power lines and utility poles, bringing down extensive portions of the infrastructure that delivers power.

Snow and Ice

Winter storms are a threat to electrical equipment when snow and ice build up on power lines and tree limbs. The weight of the snow and ice can cause wires to break. Tree limbs also become heavy with snow and ice causing them to break and fall into power lines.

Rain and Flooding

Heavy rain and melting snow can cause flooding in some areas. Flooding can damage both overhead and underground electrical equipment.

EXTREME HEAT

During a heat wave, lines, transformers and other equipment may be overloaded because of increased electricity use. In addition to higher demand, extreme heat can cause sagging power lines, cable failures, shorted underground circuits and transformer overload resulting in service interruptions.

OTHER CAUSES OF OUTAGES

VEHICLE ACCIDENTS

Vehicles coming into contact with utility poles are a common cause of power outages. In an average year, more than 900 utility poles on DLC’s system are damaged by vehicle accidents.

SMALL ANIMALS

Small animals can cause power outages. When animals climb on equipment, such as transformers or fuses, they can cause a short circuit interrupting the flow of power.

TREES

Trees falling on power lines or tree limbs coming into contact with power lines are frequent causes of power outages, even in good weather. Tree damage is the second most common cause of power outages. Only major storms create more customer outages on DLC's system.

Momentary Outages

Momentary outages, which customers see as a dimming or flickering of their lights or even a brief loss of power, are caused by short circuits. Short circuits happen when something, such as a tree limb, comes into contact with power lines or when the lines touch each other.

When a short circuit occurs, a safety device called a breaker automatically deenergizes the circuit and interrupts the flow of power. Electrical equipment is designed to quickly open and close the breaker two or three times automatically attempting the clear the problem. This is the case when a tree limb blows into a line and then swings clear.

Approximately 30 percent of short circuits clear themselves. If the problem does not clear itself, we send a Trouble Shooter out to locate the source of the problem and clear the line.