go-to app for landscape professionals
Voltage Drop Calculator
Drop
last fixture
wire gauge or a higher voltage tap.
Wire Gauge Comparison
Voltage at the Last Fixture
The voltage at the last fixture should be at least 10V.
We recommend at least 10.5V.
How did we calculate this?
We used the standard voltage drop formula, where the drop is calculated by considering the wire size and material, the current of the circuit, the voltage of the transformer, and the length of the wire run. We then compare your selected wire gauge to the four closest wire gauges to determine the best wire for your project.
Vd = (2 x K x I x L) / C
- Vd = Voltage Drop (in volts).
- K = Resistance of the wire material and gauge per 1,000 feet.
- I = Current (in amps), which is Total VA divided by the Transformer Voltage (I = VA / Vt).
- L = Length of the wire run (in feet).
- C = Circular mils (CM), a measure of wire cross-sectional area.
Terminology
Transformer Voltage:
This is the voltage supplied by the transformer to power the lighting system. For low-voltage outdoor lighting, the standard transformer voltage is typically 12 volts.
Wire Gauge:
The wire gauge refers to the thickness of the wire. Thicker wires have lower resistance and thus experience less voltage drop. Common wire gauges for outdoor lighting range from 10 AWG to 16 AWG.
Total VA (Volt-Amps):
Total VA represents the total power consumed by all the lighting fixtures in the system. It's calculated by summing the VA ratings of the individual fixtures.
Length:
This refers to the total length of the wire run from the transformer to the farthest fixture and back. Longer wire runs result in higher voltage drop.
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Wire Gauge Comparison
Voltage at the Last Fixture
The voltage at the last fixture should be at least 10V.
We recommend at least 10.5V.
Terminology
Wire Gauge (AWG)
The wire gauge refers to the thickness of the wire. Thicker wires have lower resistance and thus experience less voltage drop.
Tap - Transformer Voltage (Vt)
This is the voltage supplied by the transformer to power the lighting system. For low-voltage outdoor lighting, the standard transformer voltage is typically 12 volts (12V).
Total Volt-Amps (VA)
Total VA represents the total power consumed by all the lighting fixtures in the system. Itâs calculated by summing the VA ratings of all the individual fixtures.
Circuit Length
This refers to the total length of the wire run from the transformer to the farthest fixture and back. Longer wire runs result in higher voltage drop.
How did we calculate this?
We used the standard voltage drop formula, where the drop is calculated by considering the wire size and material, the current of the circuit, the voltage of the transformer, and the length of the wire run. We then compare your selected wire gauge to the four closest wire gauges to determine the best wire for your project.
Vd = (2 x R x I x L) / C
- Vd = Voltage Drop (in volts).
- R = Resistance of the wire material and gauge per 1,000 feet.
- I = Current (in amps), which is Total VA divided by the Transformer Voltage (I = VA / Vt).
- L = Length of the wire run (in feet).
- C = Circular mils (CM), a measure of wire cross-sectional area.
