Power outage restoration and causes

Restoration sequence

1. First, we go to areas with downed equipment to make the area safe.
2. Second, we repair damaged substations, which serve large numbers of customers.
3. Next, we restore service to hospitals as well as public safety, water treatment and other critical facilities.
4. Our next priority is repairing main distribution lines serving large areas and neighborhoods.
5. As the other steps are completed, we begin working to fix outages in smaller areas and to individual homes and businesses.

Why power goes out

Unexpected outages

Power outages can occur for many reasons. Here’s a breakdown of the most common causes:

• 40% Equipment.
• 6% Weather, including lightning, wind, rain, heat, cold, snow and ice.
• 30% Fallen trees and limbs, and tree growth into power lines.
• 11% Animal contact.
• 8% Human accidents, vandalism, etc.
• 5% Miscellaneous, including mechanical damage, construction errors, fires, etc.

Values exclude extraordinary storms, transmission-related outages and planned outages.

Planned outages

We sometimes interrupt service for maintenance work. We work to inform you and your community in advance of such outages.

Momentary outages

In the context and purposes of reliability reporting, power outages of less than 5 minutes are considered momentary. Such outages are caused by wildlife, weather, trees, public, failed equipment, etc. that are present briefly and then either self-cleared and/or cleared by protective equipment.

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