Determining The Correct Wire Size For A Circuit.

Determining The Correct Wire Size For A Circuit.

Blaze Off-Road |

Some Info To Keep In Mind:

Choosing the right wire size for your DC electrical project is important, since a wire that is too small can overheat and possibly start a fire.

At Blaze Off-Road we only sell high quality motorsports battery cable. Our cable will always be stranded rather than solid copper.

To use the chart included with this technical brief, follow the instructions below.

Choosing The Correct Wire Size


A  Locate the CURRENT IN AMPS of your appliance across the top of the chart. Most electrical products include a rating label, or you can find the amperage rating in the documentation that came with the product.

B  Find circuit LENGTH IN FEET along the left side of the chart. Note that the total length of the circuit is the roundtrip distance from power source (usually the battery) to the product and back.

C  Select the CIRCUIT TYPE. Allowable voltage drop is based on whether a circuit is critical or non-critical. Most applications will not have to worry about this, but some products will specify allowable drop.

Critical circuits, with 3% allowable voltage drop, include

  • USB Chargers

  • Fridge/Freezers

  • Electronics

Non-critical circuits, with 10% allowable voltage drop, include

  • General lighting

  • Winch

  • Air Compressor

  • Dome Lights

Follow down the column until you find your circuit’s LENGTH IN FEET.

D  Intersect CURRENT IN AMPS with LENGTH IN FEET to identify the wire size.

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