What is the voltage drop for a 120V, single-phase, two-wire branch circuit, 100' long with a 13A load?

To determine the voltage drop in a 120V single-phase two-wire branch circuit, we can use the voltage drop formula:

Voltage Drop (Vd) = 2 × Length × Current × Resistance per unit length

1. First, find the total length of the circuit. Since it's a two-wire system (one hot and one neutral), the circuit's total length is effectively twice the length of the one-way distance. Therefore, if the distance is 100 feet, the total length is 200 feet.

2. The current load is given as 13A.

3. To calculate the voltage drop, we need to know the resistance of the wire per unit length. For typical copper wire sizes, the resistance per 1000 feet is approximately 2.0 ohms for a 12 AWG wire.

4. For 200 feet of a 12 AWG copper wire, the resistance can be calculated as:

Resistance = (2.0 ohms / 1000 feet) × 200 feet = 0.4 ohms.

5. Now we can use the voltage drop formula:

Vd = 2 × 100 feet × 13A × (2.0 ohms / 1000