What is the voltage drop on a single-phase, 208-volt branch circuit supplying a 54-ampere load at a distance of 98 feet using 6 AWG RHW uncoated copper conductors?

To calculate the voltage drop on a single-phase circuit, the formula used is:

[ V_{drop} = \frac{2 \times K \times I \times L}{1000} ]

where:

• ( K ) is the resistance in ohms per mil foot for the conductor material,

• ( I ) is the load current in amperes,

• ( L ) is the one-way length of the circuit in feet.

For copper conductors, the standard value of ( K ) is approximately 12.9 ohms per mil foot. In this case, you have:

• ( K = 12.9 ) ohms per mil foot for copper,

• ( I = 54 ) amps (the supplied load),

• ( L = 98 ) feet (the distance of the circuit).

Plugging in the values gives:

[ V_{drop} = \frac{2 \times 12.9 \times 54 \times 98}{1000} ]

Calculating the above step-by-step:

1. ( 2 \times 12.9 = 25.8 )

2. ( 25.8 \times 54 = 1391.