The Importance of Tree Trimming for Public and Electric Grid Safety

Trees and power lines don’t mix, but with the right approach, they can coexist safely. Santee Cooper performs tree trimming to preserve public safety and the reliability of the electric grid. Additionally, there are requirements set forth by the North American Electric Reliability Corporation (NERC) we must meet.

Most of the tree trimming that we do is on our easements that are located on privately-owned properties. We cut and trim trees to ensure they don’t make contact or get close enough to cause an operation on the system, leading to a system fault where the lights go out.

Three Main Types of Trimming

Cycled side trimming: This is planned vegetation maintenance that focuses on trimming back growth or branches to keep the edges of the right of way clear. This type of trimming is typically carried out using bucket crews, a sky trim (jarraff), or a helicopter equipped with a vertical saw.

Hazard tree cutting: This is more emergent in nature and addresses trees that are dead, diseased, leaning, or otherwise posing an immediate threat to power lines. These are typically referred to as “patrol items,” as they are normally reported from our annual patrols (inspections). This is generally done with either bucket crews or a saw helicopter (vertical saw or topping saw).

Danger tree cutting: This is planned vegetation maintenance and focuses on cutting back, usually at a 45-degree angle, trees that are otherwise green and healthy, but could hit the transmission lines if they were to fall. This process is necessary because most tree-related outages result from these healthy, tall trees located just outside the right-of-way. Bucket crews and helicopters with topping saws are used for this work.

Post-Trimming Cleanup and Public Safety

Following tree trimming, a ground-based crew typically performs cleanup operations, which usually occurs a few weeks after trimming unless debris is in a high traffic area or could cause a public safety issue.

Tree trimming is ultimately a public safety measure. If vegetation is not managed properly, it can lead to fire hazards, power outages, and increased safety risks. Any tree that contacts a power line can cause an outage, leading to situations where residents may be left without heating, air conditioning, or other essential utilities.

By proactively managing vegetation, we ensure reliable electricity service while prioritizing public safety and compliance with federal regulations.

For more information, please visit our Tree Management page on our website.