Overhead Powerline Clearance Calculator

The calculator estimates the closest distance between a power line and the nearest equipment point.

• Line height relative to equipment ground: H_line_rel = H_line + Δground
• Boom tip height (boom mode): H_tip = H_pivot + L_boom · sin(θ)
• Horizontal reach toward the line: R_toward = L_boom · cos(θ) · |cos(φ)|
• Horizontal separation: S_h = D_base_to_line − R_toward (direct mode uses measured S_h)
• Vertical separation: S_v = H_line_rel − H_point
• Minimum 2D distance: S = √( |S_h|² + |S_v|² )
• Required distance: Required = MAD + Buffer (MAD depends on voltage or a fixed planning boundary)

Notes: This is a simplified 2D approach. Wind, sag, dynamic swing, uneven terrain, and rigging behavior can reduce real clearance.

1. Confirm the line voltage with the utility owner/operator.
2. Measure the line height and ground difference at the closest span.
3. Choose your input method: boom geometry for cranes/booms, direct for measured clearances.
4. Enter boom length, pivot height, angle, and orientation—or enter direct height and separation.
5. Add a safety buffer to account for motion, wind, sag, and uncertainty.
6. Press Calculate Clearance and review the pass/fail result.
7. Download CSV/PDF to document your lift plan and controls.

Common voltage-based minimum approach distances (MAD) for equipment operations:

Always follow your local rules and the utility’s requirements.

1) Why clearance planning matters

Overhead conductors can arc without contact, so planning keeps people, loads, and equipment outside the minimum approach distance. A clearance check converts field measurements and boom geometry into a repeatable decision, reducing last‑second judgment during lifting, spotting, and travel. It also supports toolbox talks and pre‑task briefings.

2) Voltage classes and approach distances

Required separation rises with voltage. Confirm the nominal line voltage (kV) with the owner/operator, then apply the matching minimum approach distance. If voltage is uncertain, select the highest credible value until verification is obtained and recorded.

3) Measuring line height and terrain

The tool uses line height at the closest span plus the ground level difference between the equipment base and the line location. Slopes matter: a 3 ft drop from base to line reduces vertical clearance by 3 ft. Measure at the working position, not the access road.

4) Accounting for sag, sway, and weather

Conductors move. Temperature and loading affect sag, and wind can cause lateral swing. Equipment motion adds dynamic overshoot. Add buffer for uncertainty; on windy days or long spans, conservative planning buffers (often 3–10 ft) help protect against changing conditions.

5) Boom geometry and working envelope

For cranes and booms, tip height is estimated from boom length, pivot height, and boom angle. This supports pre‑lift envelope checks. If the boom can slew, the closest approach may occur in a different orientation, so test multiple angles and positions.

6) Buffers, spotters, and limit devices

Use the buffer input to represent load swing, measurement error, line movement, and operator response time. A dedicated spotter improves control but does not replace clearance. Where available, set swing limits, height limits, or proximity alarms to match the planned boundary.

7) Work zones, signage, and permits

Establish an exclusion zone with cones, tape, and signage that meets or exceeds the required distance. For repeated operations, mark a clear “no‑go” arc on the ground near spans. If the utility requires permits, covers, or de‑energization, include them in the method statement.

8) Documenting results and daily re-checks

Export inputs and outcomes for traceability, including who measured, when, and where. Re-check after repositioning, ground changes, or switching to a different span. Keep the permit, utility notes, and a quick sketch with the lift plan. Short daily verification prevents yesterday’s safe setup becoming today’s near miss.

1) What does MAD mean in this calculator?

MAD is the minimum approach distance: the smallest allowed separation from an energized overhead line. The calculator compares your worst-case clearance (after buffer) to MAD to return a pass/fail planning result.

2) What voltage should I enter if the line is unknown?

Do not guess low. Treat the line as the highest plausible voltage for the corridor until the owner/operator confirms the value. Update the input once verified and keep the confirmation in your job file.

3) How do I measure base-to-line distance?

Measure the horizontal distance from the operating base reference (or outrigger footprint) to the vertical projection of the closest conductor. Use the closest approach path, not a convenient tape line.

4) Does the result include conductor sag?

No. Enter the line height you observed and add buffer for sag, wind, and temperature effects. If conditions change, re-measure the height and recalculate.

5) What buffer value is reasonable?

Use a buffer that reflects site risk. For controlled work on stable ground, a few feet may be used. For slewing, traveling, or windy conditions, apply larger buffers based on the job plan.

6) Can I use this for lifts, telehandlers, or scaffolds?

Yes, as a planning check. Use direct inputs for measured clearances, or boom geometry for articulated equipment. Always follow the equipment manual, site rules, and utility requirements.

7) Why did pass/fail change when I changed the boom angle?

Boom angle changes tip height and horizontal reach. A steeper angle may increase height but reduce reach, while a flatter angle may do the opposite. Check the angles and orientations you will actually use.