Last updated: Jul 25, 2024

12 Volt Wire Size Calculator

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Table of contents

How to calculate the size of a 12 volt wire?How do you use this 12 V wire size calculator?Other useful tools like the 12 volt wire size calculator FAQs

The 12-volt wire size calculator will help determine the appropriate electrical wire for your next house installation. Do you want to install a new camera or motion-sensing light? Please keep reading to determine how to size your cables.

How to calculate the size of a 12 volt wire?

We will use the resistivity concept and combine it with the ohm's law for a single conductor:

\quad A = \frac{2\times I \varrho L}{V \times \%_{\text{drop}}}

where:

$\%_{\text{drop}}$ — Allowable voltage drop, in %.
$V$ — Source voltage, measured in volts.
$I$ — Maximum current running through the wire, measured in amps;
$\varrho$ — Resistivity of the conductor material, measured in ohm meters;
$L$ — Length of the wire, measured in meters; and
$A$ — Cross-sectional area of the wire measured in square meters.

We add factor 2 because we have one way from the source to the equipment and another one way from the equipment to the source.

How do you use this 12 V wire size calculator?

You need to verify that your equipment can withstand 12 volts. Then you follow these steps:

12-volt AC / DC is already set for you. Now, we have to define the allowable voltage drop.
Select the conductor's material, either copper or aluminum. You can also select Other to enter a custom conductor resistivity value.
Define how much current (amperes) your equipment needs.
Indicate the one-way length of your electrical system.
Finally, specify the maximum operating temperature.

Our 12 V wire size calculator will indicate the cross-sectional area, cable diameter, and AWG size.

Other useful tools like the 12 volt wire size calculator

Since you already know how to size a 12 volts wire, you can take a look at other calculators:

FAQs

Which size wire is recommended for 12 volts appliances?

You have to define the amperes your equipment needs as it directly impacts the 12-volt wire size calculation. However, if we:

Add five amps into the Omni Calculator 12-volt wire size.
Include the allowable voltage drop (maximum 5% for DC appliances).
Finally, add the one-way length of our system (here, we assume 7 m) and the max operating temperature; then, we get a 13 AWG wire.

Can I use 16 AWG wire for 12 volts applications?

It will depend on the maximum current you will have in the conductor. The Omni Calculator 12-volt wire size can help you:

Add the maximum wire area corresponding to 16 AWG: 1.308 mm².
Set the maximum operating temperature. By default, 50 °C.
Define the one-way distance (5 meters) and the maximum allowable voltage drop (3%). As a result, the maximum current is 2.5 amperes.

How many amps can a 14 AWG wire withstand on a 12-volts system?

3.97 amperes as per Omni Calculator's 12-volt wire size tool. To get such a result, we need:

Add the wire area corresponding to 14 AWG: 2.08 mm².
Add a one-way distance of 5 meters.
Include an allowable voltage drop of 3%.
Define a maximum operating temperature of 50 °C.