Wire Gauge For 20 Amp Circuit: 20A Wire Size + 100 Feet Away

Whether you are working on a 20-amp or 30-amp breaker, the importance of wire size cannot be denied. Different factors help to use the wire. The commonly used factor is a gauge, also called AWG or American Wire Gauge. Gague is a wire measurement in diameter. AWG is the standard system used for wire measurement. Wire gauge is measured from high to low, with a lower number indicating a smaller size of wire. Let’s discuss the wire gauge for a 20-amp circuit: 20A Wire Size + 100 Feet Away

What is a 20-amp circuit?

The 20-amp circuit is normally referred to as the amp rating. It finds the amount of current flow. Most devices used in our homes have a rating of 20 amps or 15 amps. It is helpful to know which type of wire you should use. The rating defines the amount of current that passes through the circuit. AMP is a unit that is used for measurements. The rating of the amp is related to the wire size. It is also used to find the circuit breaker amp rating connected to it. Mostly 20-amp circuits are connected with 12-gauge or 10-gauge wire. With that, a 14-gauge wire is also connected that can carry 15-amp current. For a 20-amp circuit, it is suggested to use a 12-gauge wire. Use of a 14-gauge wire at 20 amps will cause overload, overheating, and fire.

Wire Gauge For 20 Amp Circuit


Here is the chart for the wire ampacity of copper material that is made.

Maximum Amps 7 10 15 20 30 40 55 70 95
Gauge (wire size) 18 16 14 12 10 8 6 4 2

Can 14-gauge wire be used on a 20-amp circuit?

14 AWG wires carry a maximum current of 15 amps. If the load gets a higher current than 15 amps on a 15-ampere circuit, the breaker will trip, protecting the 14 A AWG wire. If the circuit is 20 ampers, the breaker will not trip when the current is greater than 15 ampers.

In simple words, a 14-gauge wire can be used for a 20-ampere circuit if the load is under 15 amps. Such as a 20-amp circuit that operates lights in houses made with 14-gauge wires. It can be a risky process.

What wire gauge for a 20-amp circuit? (Apply the NEC 80% Rule.)

There are 2 wire sizes used for 20 amps, according to NEC’s 80 percent rule.

Wire Gauge Ampacity (A)
#14 AWG 20
#12 AWG 25
#10 AWG 35

14 AWG wire normally does not use a 20-amp circuit. But 12 AWG wires and 10 AWG wires were used. The 80%%rule can be used to meet the minimum requirements of an ampacity of 20 amp.

20 Amp Wire = 20A × 100% / 80% = 25A Ampacity

So there is a need for 25A ampacity wire for 20 amps.

What Size Wire Is For 20 Amps At 100 Feet Away?

When current flows through 100 feet or more of distance, the voltage will decrease. For having a complete 20-amp range, there is a need for a voltage booster to handle the voltage losses. The boosting amp is normally connected with a longer wire. The boosting amp is normally connected with a large wire. normally a 100-foot circuit or more with a 20-amp current. If we follow the NEX310-16 rule that says for copper and aluminum 20-amp wires, there is a need to increase the amp by 20 percent for each 100-foot distance.

We find the 25A ampacity wire used for the 20A circuit. If we have to connect 20 amps for a 100-foot distance, this increases the minimum ampacity of the wire by about 20 percent. Here we find

20 Amp Wire for 100 feet = 25A × 1.2 = 30A Ampacity

which means that 12 AWG wire with a 25 amper ampacity will not be enough. That wire must be used for a 20-amp, 220-volt circuit 100 feet long.

Wire Gauge For 20 Amp Circuit 20A Wire Size + 100 Feet Away

How many outlets are there on a 20-amp circuit breaker?

The number of outlets on a 20-amp circuit can be connected according to need. It is best to use it when many outlets are needed for power distribution. However, there are chances of overheating the wire, which can affect the other devices connected to the circuit. With an accurately designed load configuration, we measured several outlets for the 20-amp circuit breaker.

Watts = amps x volts

Normally in our homes, a 120-volt circuit is connected, and the current flow is 20 amps. So we can use about 2400 watts for a 20-amp circuit and 20 volts. Normally, we connect about 13 devices on a 20-amp circuit. 13 devices with 1.5 amps will use 19.5 amps; this is theoretically possible but not practical. It is the reason that if we use 90 percent of the circuit, it can be tripped. So according to the 80 percent rule, limit the load in the circuit and breaker to 80 percent or less used. According to the 80 percent rule, 20 amps makes it 16 amps. It is 1920 watts on a 120-volt circuit. OS 10 outlets for a 20-amp circuit are best to use according to this formula.

1.5 amps x 16 amps = 10.67 devices

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