Class | Circumference at Top | Circumference at 6 Feet from Butt | Strength | Common Uses | Typical Length |
Class 1 | 42 inches | 27.5 inches | Highest load-bearing capacity | High-voltage power lines, critical infrastructure | 40 to 90 feet |
Class 2 | 37.5 inches | 25.5 inches | Very high load-bearing capacity | Major distribution lines, street lighting | 35 to 90 feet |
Class 3 | 33 inches | 23.5 inches | High load-bearing capacity | General distribution lines, medium-duty applications | 30 to 80 feet |
Class 4 | 28.5 inches | 21.5 inches | Good load-bearing capacity | Standard utility poles, telecommunications | 25 to 75 feet |
Class 5 | 24 inches | 19.5 inches | Moderate load-bearing capacity | Light-duty distribution lines, secondary power lines | 25 to 65 feet |
Class 6 | 19.5 inches | 17.5 inches | Lower load-bearing capacity | Service poles, light-duty applications | 20 to 60 feet |
Class 7 | 15 inches | 15.5 inches | Lowest load-bearing capacity | Minimal structural requirements, temporary structures | 20 to 55 feet |