2 V is the example result. Read it using the units and relationship stated below.
Cable Voltage Drop uses one-way length (ft), current (a), conductor resistance (ohm/ft).
Distinguishing electrical arithmetic from equipment selection
For cable voltage drop, the relationship is Single-phase/DC two-conductor voltage drop (V) = 2 × one-way length (ft) × current (A) × resistance per conductor (ohm/ft). This excludes reactance and is not the three-phase relationship. The amount depends on the supplied one-way length (ft), current (a), rather than a live market price or a value imported from another record. Power, energy, voltage and current describe different quantities. Watts represent a rate; watt-hours represent energy over time. Battery and inverter losses can reduce usable runtime even when the rated capacity is unchanged.
What the model includes
Single-phase/DC two-conductor voltage drop (V) = 2 × one-way length (ft) × current (A) × resistance per conductor (ohm/ft). This excludes reactance and is not the three-phase relationship. Read unit labels before comparing results. Motor estimates depend on phase, efficiency and power factor; energy budgets depend on duration and duty cycle. Nameplate values and measured consumption may differ under real loads. Treat the output as the stated estimate. It does not select a code-compliant conductor, protective device or complete installation. Equipment specifications and applicable requirements remain part of the design decision.
Example with the supplied inputs
One-way length (ft): 50; Current (A): 20; Conductor resistance (ohm/ft): 0.001. Result: 2 V. The values are illustrative.
Compare one changed input
One-way length (ft) changes from 50 to 55. The result becomes 2.2 V. All other inputs remain fixed.
Calculation rule
Single-phase/DC two-conductor voltage drop (V) = 2 × one-way length (ft) × current (A) × resistance per conductor (ohm/ft). This excludes reactance and is not the three-phase relationship.
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| One-way length (ft) | 50 | Measure one-way length (ft) in the displayed unit. Convert the source measurement before entry if it uses another system; a changed label does not perform a unit conversion. |
| Current (A) | 20 | Use the source quantity represented by current (a). Keep the counted population fixed and avoid mixing a unit value with a period total. |
| Conductor resistance (ohm/ft) | 0.001 | Use the source quantity represented by conductor resistance (ohm/ft). Keep the counted population fixed and avoid mixing a unit value with a period total. |
Output: 2 V is the example result. Read it using the units and relationship stated below. Unit: V.
How to use the page
Collect the inputs
Gather One-way length (ft), Current (A), Conductor resistance (ohm/ft). Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change One-way length (ft) on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 2 V.
Change One-way length (ft) from 50 to 55 while keeping every other value fixed. The result becomes 2.2 V. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026