Field tool
Voltage-drop calculator
Estimate the voltage at the far fixture of a low-voltage landscape run, plus the percent drop and a wire-gauge recommendation. Pass threshold = 10 percent.
Inputs
Results
- Voltage at fixture
- 9.35 V
- Voltage drop
- 2.65 V
- Percent drop
- 22.1 %
- Status
- FAIL
Recommendation
Upsize wire to 10 AWG
Formula
Vdrop = 2 × I × R_per_ft × L, where I = total watts / tap voltage and R_per_ft is per NEC Table 8 at 25 °C. Round-trip current path = factor of 2.