Long Distance Feeder Voltage Drop Solutions
Strategies for managing voltage drop in long feeder runs. Covers voltage optimization, sub-panel placement, and economic analysis for extended electrical distribution.
The Long Distance Challenge
Long feeder runs are common in industrial facilities, campus environments, agricultural operations, and distributed commercial buildings. These extended circuits present significant voltage drop challenges because voltage drop is directly proportional to distance. A feeder that would easily meet the 3% recommendation at 100 feet may require substantial conductor upsizing at 500 feet.
This guide explores practical strategies for managing voltage drop in long feeder applications, including conductor optimization, strategic sub-panel placement, and economic analysis to find the most cost-effective solution.
Strategy 1: Conductor Upsizing
The most straightforward approach to reducing voltage drop is using larger conductors. Each step up in wire gauge reduces resistance by approximately 26%, directly reducing voltage drop by the same percentage. However, larger conductors cost more and require larger conduit, so there's an economic limit to this approach.
Example: 200A Feeder at 500 ft
Strategy 2: Voltage Optimization
Using higher voltage distribution reduces current for the same power, directly reducing voltage drop. For example, distributing at 480V instead of 208V for the same kVA load reduces current by more than half, dramatically improving voltage drop performance.
208V Distribution
100 kVA load = 278A
Higher current, more drop
480V Distribution
100 kVA load = 120A
57% less current, less drop
Strategy 3: Sub-Panel Placement
Rather than running individual circuits over long distances, installing a sub-panel closer to the loads can be more economical. The feeder to the sub-panel can be sized for the total load, while branch circuits from the sub-panel are kept short.
- Feeder to sub-panel: Single larger circuit optimized for the total load
- Branch circuits: Short runs from sub-panel to individual loads
- Benefits: Reduced total conductor cost, easier maintenance, expansion capability
Optimize Your Long Feeders
Use our calculator to compare different conductor sizes and configurations for your long feeder runs. Find the optimal balance between voltage drop performance and installation cost.
Feeder Calculator