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Voltage Drop Pro

Voltage drop calculator with wire size recommendations

Features

Instant Voltage Drop Calculation

Enter your circuit parameters and get immediate voltage drop calculations. Shows both percentage and actual voltage drop.

NEC Compliance Checking

Automatically checks against NEC 210.19(A) for branch circuits and 215.2(A) for feeders. Know instantly if your design meets code.

Wire Size Recommendations

Get automatic wire size recommendations that meet voltage drop requirements. Saves time on manual calculations.

Copper & Aluminum Support

Full support for both copper and aluminum conductors with accurate resistance values for each material.

All Standard Wire Sizes

Includes all standard wire sizes from 14 AWG through 1000 kcmil. Complete coverage for any installation.

Single & Three Phase

Handles both single-phase and three-phase calculations with proper formulas for each system type.

Screenshots

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Frequently Asked Questions

What is the NEC voltage drop limit?

The NEC recommends a maximum voltage drop of 3% for branch circuits (210.19(A)) and 5% total from service to the farthest outlet. For feeders, 215.2(A) recommends 2% maximum when combined with branch circuit drop. Voltage Drop Pro automatically checks your calculations against these limits.

Does voltage drop affect wire ampacity requirements?

No, voltage drop and ampacity are separate considerations. You must size conductors to meet both ampacity requirements (based on load and NEC Table 310.15(B)(16)) AND voltage drop limits. Always verify the larger of the two wire sizes is used.

Should I use copper or aluminum wire?

Copper has better conductivity and requires smaller wire sizes, but aluminum is more cost-effective for large feeders. Aluminum requires larger sizes for the same voltage drop. This app helps you compare both options to make the best choice for your installation.

How do I measure circuit length for voltage drop?

Measure the one-way distance from source to load. The app automatically accounts for the return path in its calculations. Include any vertical runs and routing around obstacles for accurate results.

Get Voltage Drop Pro Today

Stop guessing at wire sizes. Get accurate voltage drop calculations instantly.

Download on the App Store - $1.99