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Voltage Drop Calculator

Review voltage drop for long runs.

Key takeaway

  • Calculate voltage drop for long-run planning.
  • Adjust conductor size if voltage drop exceeds limits.

Reviewed by ConstructionBids.ai Team. Last updated .

Circuit Details

Calculation Results

Within planning target
0.00%
Voltage Drop Percentage
Voltage at Load
0.0 V
Actual voltage reaching equipment

Details

Voltage Drop0.00 Volts
Max Length for 3% Drop0 ft
Based on NEC Chapter 9, Table 8 resistance values. Assumes 75°C conductor temperature.
A common planning target is 3% drop for branch circuits. Verify project and code requirements before final use.

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Voltage Drop Calculator for electrical estimators and field leads

Voltage Drop Calculator helps electrical estimators and field leads avoid undersized conductors. Enter run length, load, and conductor size and get voltage drop percentage you can use immediately in your bid or project file.

Built for common US construction workflows, including municipal, state, federal, commercial, and subcontractor bid documentation.

Calculate voltage drop for long-run planning.

Quick answer: what does this tool do?

Calculate voltage drop for long-run planning.

How should I apply the results?

Adjust conductor size if voltage drop exceeds limits.

Is this suitable for public bids?

Yes. The inputs align with typical DOT, municipal, and federal bid requirements.

What keywords does this tool target?

voltage drop calculator nec, wire size calculator voltage drop

How to use the Voltage Drop Calculator

  1. 1Enter run length and load
  2. 2Select conductor size
  3. 3Review voltage drop
The Voltage Drop Calculator gives electrical estimators and field leads voltage drop percentage. It supports avoid undersized conductors with clear definitions, bid-use cases, and related questions contractors can review before they act.

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