12 Volt Wire Size Calculator

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Arturo Barrantes

Arturo Barrantes is a versatile professional who transitioned from mechanical engineering to finance and then to software development. Currently working as an AWS Senior Developer at Indra, he combines his diverse expertise to create practical financial calculators. Arturo is passionate about financial education in Latin America and has spoken at multiple conferences on personal finance and investment strategies. See full profile

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Wojciech Sas, PhD

Wojciech Sas

PhD, Institute of Physics in Zagreb

Wojciech, PhD, is a physicist at the Institute of Physics in Zagreb, investigating materials under extreme conditions such as low temperatures and high pressures. He specializes in experimental work, including participation in Large-scale User Facilities such as synchrotrons. Wojciech uses his experience and knowledge to create calculators in physics, math, and statistics categories. In his free time, he likes swimming, playing board games, and looking for meteors while stargazing. See full profile

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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.