100 Amp Wire Size Calculator

The 100 amp wire size calculator will help you determine the appropriate electrical wire for your next whole-house or three-phase equipment installation. Keep reading to find out how to size your cables.

The following information is required before we start:

• Wire size material since it affects the electrical resistivity.
• Distance between your energy source and the equipment you want to energize.
• The voltage at which your system will run.
• System configuration: Single-phase / Three-phase

Once we have it all, we will use the following formula:

where:

• $\%\text{drop}$ — Allowable voltage drop, in %. For a 100 amps system, keeping a maximum 3% of voltage drop is strongly recommended.
• $V$ — Source voltage, measured in volts.
• $I$ — System current, measured in amperes.
• $\varrho$ — Resistivity of the conductor material, measured in ohmmeters;
• $L$ — Length of the wire, measured in meters; and
• $\phi$ — Phase factor, 1 for AC single phase and $\sqrt{3}/2$ for AC three-phase.
• $A$ — Cross-sectional wire area measured in square meters.

The result will be expressed in mm² (if using the metric system).

It is common for wires to indicate their size in AWG (American Wire Gauge) units. Our wire gauge calculator relates circular cross area in mm² to AWG, but do not worry; our 100 amp wire size calculator also provides results in AWG.

To find the wire size suitable for your application, follow these steps:

1. Verify your connection will be a 100 amp alternate current.
2. Choose the electrical system configuration: single or three-phase. Then, specify the voltage source.
3. Define the wire material you will use, the operating temperature, and the voltage drop.
4. Finally, input the length of your cable (remember, it's a one-way distance).

As a result, the 100 amp wire size calculator will indicate the cross area of the cable you need to install.

Since you already know how to size a 100 amp wire, you can take a look at other calculators:

• Wire size calculator;
• 220 volt wire size calculator;
• DC wire size calculator;
• 12 volt wire size calculator;
• Amp to wire size calculator; and
• 24 volt wire size calculator.