Calculator
Voltage Drop Chart
Formula Used
DC or single phase: Voltage Drop = 2 × Length × Current × Resistance per 1000 ft ÷ 1000.
Three phase: Voltage Drop = 1.732 × Length × Current × Resistance × Power Factor ÷ 1000.
Load Voltage: Source Voltage − Total Voltage Drop.
Drop Percent: Voltage Drop ÷ Source Voltage × 100.
How to Use This Calculator
Enter the source voltage, load current, and one way wire length. Select copper or aluminum 10 AWG wire. Choose the circuit type. Add power factor for AC loads. Add temperature and connection resistance if known. Press calculate. The result appears above the form.
Example Data Table
| Voltage | Current | Length | Material | Drop | Load Voltage |
|---|---|---|---|---|---|
| 120 V | 20 A | 50 ft | Copper | 2.00 V | 118.00 V |
| 240 V | 30 A | 80 ft | Copper | 4.80 V | 235.20 V |
| 120 V | 15 A | 70 ft | Aluminum | 3.34 V | 116.66 V |
About 10 AWG Load Voltage Calculations
Why Load Voltage Matters
Load voltage is the voltage that reaches the device. It is often lower than the source voltage. Wire resistance causes this reduction. Longer conductors create more drop. Higher current also increases the loss. A low load voltage can reduce performance. Motors may run hotter. Lights may dim. Electronics may behave poorly.
Role of 10 AWG Wire
10 AWG wire is common in branch circuits, equipment feeds, and workshop wiring. Copper has lower resistance than aluminum. That means copper usually gives less voltage drop at the same length and current. Aluminum can still work, but it needs careful planning. Always follow local electrical codes and equipment ratings.
Advanced Inputs
This calculator includes temperature correction. Wire resistance rises as temperature increases. It also supports connection resistance. Loose terminals, splices, and old connectors can add small resistance. That small value can matter at higher current. A safety margin helps plan for field conditions.
Reading the Result
The voltage drop percentage shows how serious the loss is. Many designs target low drop for better efficiency. A drop near three percent is often acceptable for many branch circuits. A higher value may need shorter wiring, larger conductors, or lower current. The chart helps compare the source and delivered voltage.
FAQs
1. What does this calculator find?
It estimates voltage drop, load voltage, drop percentage, wire loss, and useful power for a 10 AWG wire circuit.
2. Does it support copper wire?
Yes. It includes copper 10 AWG resistance and adjusts that value when temperature changes from the reference condition.
3. Does it support aluminum wire?
Yes. Select aluminum when the circuit uses aluminum 10 AWG conductors. It has higher resistance than copper.
4. Why enter one way length?
The calculator applies the return path factor automatically for DC and single phase circuits. Enter only the one way distance.
5. What is power factor?
Power factor adjusts AC load calculations. Use 1 for resistive loads. Motors often use a lower value.
6. What is connection resistance?
It represents added resistance from terminals, splices, plugs, breakers, and connectors. Use zero when unknown.
7. What voltage drop is acceptable?
Many designs aim for about three percent or less. Sensitive equipment may need a stricter target.
8. Is this a code compliance tool?
No. It is an estimating tool. Always verify conductor size, protection, and installation with applicable electrical rules.