Facility Management units in educational settlements rarely deal with tree obstruction on overhead supply sources except where off-campus sources provide power to agricultural units. The NESC does not provide specific tree‑species or pruning schedules—that is often left to local utility standards guided by NESC clearances. The IEEE Education & Healthcare Facilities Committee deals with these borderline cases, often collaborating with the IEEE Rural Electric Power Conference.
NESC Minimum Vertical Clearances (Rule 232)
| Voltage (kV) | Minimum Vertical Clearance (ft) |
|---|---|
| 0 – 750 V | 12 ft |
| 0.75 – 22 kV | 18 ft |
| 22 – 46 kV | 22 ft |
| 46 – 72.5 kV | 26 ft |
| 72.5 – 121 kV | 30 ft |
| 121 – 145 kV | 32 ft |
| 145 – 230 kV | 37 ft |
| 230 – 345 kV | 40 ft |
| 345 – 500 kV | 44 ft |
| 500 – 750 kV | 50 ft |
NESC Minimum Lateral Clearances (Rule 234)
| Voltage (kV) | Minimum Lateral Clearance (ft) |
|---|---|
| 0 – 750 V | 3 ft |
| 0.75 – 22 kV | 3 ft |
| 22 – 46 kV | 4 ft |
| 46 – 72.5 kV | 5 ft |
| 72.5 – 121 kV | 6 ft |
| 121 – 145 kV | 6 ft |
| 145 – 230 kV | 8 ft |
| 230 – 345 kV | 10 ft |
| 345 – 500 kV | 12 ft |
| 500 – 750 kV | 14 ft |
2022 Guide for Animal Deterrents for Electric Power Supply Substations
