How do the parameters of wire length and AWG and ampacity affect THHN cable

For master construction engineers, the relationship between THHN cable length, specification and current carrying capacity is a common concern of our customers. Let us assess the difference between these three in simple terms.

What is the definition of length, AWG and ampacity

The length of THHN cable you buy depends on the length of cable you need from point A to point B.

AWG or American Wire Gauge is the standard measurement of THHN cable conductor size used in the United States, North America, and certain countries around the world. Small gauge indicates the maximum diameter of THHN cable conductors. For example, 2 AWGTHHN THWN-2 stranded copper construction wire is much larger than 14 AWG THHN THWN-2 solid copper construction wire. Gauges between 2 and 14AWG are the most common gauges on the market. When buying a THHN cable, you always choose a specific specification, an accurate measurement of the size of the THHN cable.

Amperage is a common term for the strength of current. The term amperage is related to THHN cable circuits. However, when it comes to THHN wire and cable, a more relevant term is ampacity, which is the maximum amount of current a THHN wire and cable conductor can carry in the environment in which it is used, while adhering to its advertised temperature rating. THHN cable amperage is measured in amperes, or simply amperes. The magnitude of the ampacity can be used in the circuit. For example, cables in private residential circuits used for home wiring typically carry 20 amps, while lighting circuits require a lower current capacity of 15 amps.

How are length, AWG and ampacity related?

The higher the amperage of the circuit, the higher the ampacity of the THHN cable and the smaller the gauge. The THHN cable should be thick enough to handle a specific amperage so it doesn't heat up to critical temperatures.

Does THHN wire length affect current flow?

The length of the THHN wire has no direct effect on the amperage, but has an effect on the voltage across the resistor. The longer the THHN wire, the higher the THHN cable resistance and voltage drop.

Resistance is a term for how THHN wire or THHN cable resists the flow of current. The measurement of resistive impulse is the voltage drop, a term that represents the reduction in electrical potential of the cable in the current. A voltage drop of less than 3% is acceptable. If the resistance of a particular THHN cable does not affect the voltage drop by more than 3%, the effect of wire length on the resistance is not significant, and the THHN cable works well without heating. In some cases, if the THHN cable is too long, you may have to use a smaller gauge than others. This is mostly only relevant for very long THHN cables.

Okay, the above is the introduction on "How do the parameters of wire length, AWG and ampacity affect THHN cable selection?", I hope it can help everyone! It is recommended to continue to pay attention to Jianzhenda Cable to learn more about THHN wire and cable information.