Okay, let's break down the height requirements for overhead service conductors (since you're feeding another building, we'll treat this as a service to that building from your perspective). You're right to be concerned about the height; it's a critical safety issue.Here's a summary, along with the relevant NEC (National Electrical Code) sections. Keep in mind that local amendments can supersede the NEC, so always check your local codes.

Summary of Height Requirements (120/240V)



General Clearance

The most common height requirement for 120/240V overhead service conductors is

10 feet (3.0 m). Over Residential Driveways

The height over residential driveways is also

10 feet (3.0 m). Over Areas Subject to Truck Traffic

If the area is subject to truck traffic, the clearance requirements go up significantly. This is where it gets tricky and you will need to use Table 230.24(B).

Above Finished Grade, Sidewalks, or From Platforms or Projections



10 feet (3.0 m).

NEC Code Sections to Consult

The primary section you'll be looking at is

NEC 230.24 - Clearance of Service Drops. Here's a breakdown of the subsections that are relevant: 230.24(A) - Above Roofs

This section applies if your conductors pass over roofs. I assume that they do not.

230.24(B) - Vertical Clearance from Ground

This is the one you need to focus on. This is the key section for ground clearance. It states that service-drop conductors shall have the following clearances from final grade. It's supplemented by a table for easy use.

NEC Table 230.24(B) is the crucial table that shows the required clearances.

How to Apply the Code


Determine the Area

Carefully analyze the area under the overhead conductors. Is it just a yard? A sidewalk? A residential driveway? An area subject to truck traffic?2.

Use Table 230.24(B)

Look up the appropriate clearance height in Table 230.24(B) based on the area you identified in step 1. For areas with only pedestrian or residential vehicle traffic, the 10-foot minimum will likely apply.
3.

Account for Sag

Remember that conductor sag can significantly reduce the clearance, especially in hot weather. Ensure that the conductors meet the minimum clearance requirements at their lowest point, even under maximum sag conditions.

Important Considerations and Cautions



Local Amendments

As mentioned before, your local jurisdiction may have stricter requirements. Always check with your local electrical inspector or building department. They have the final say.

Insulated vs. Uninsulated Conductors

While it's less common for service drops, the type of insulation on the conductors can sometimes affect the clearance requirements.

Voltage

Higher voltages require greater clearances. Since you are using 120/240, the general rule of 10 feet will normally apply.

Communication Cables

Do not confuse your service conductors with telephone or cable tv lines. The clearances are significantly different for communication lines.

Example Scenario

Let's say your overhead conductors run across a residential yard that might occasionally have a car parked there. You check NEC Table 230.24(B). For areas subject to pedestrian or restricted automobile traffic, a 10-foot clearance is required. Therefore, 10 feet would be the minimum height.

Recommendation

Because you're dealing with electrical safety and potential liability, I strongly recommend consulting with a qualified electrician. They can properly assess your specific situation, ensure code compliance, and perform the work safely. They will also have knowledge of local codes and amendments.

Disclaimer: I am an AI chatbot and cannot provide professional electrical advice. This information is for general guidance only. Always consult with qualified professionals and adhere to local codes. Flag for review