In a 120/208-volt 3Ø, 4W panelboard, how many more amps of load could you add to AØ before overloading a 45 KVA transformer?

To determine how many more amps of load can be added to phase A of a 120/208-volt 3-phase, 4-wire panelboard without overloading a 45 kVA transformer, it is essential to understand the relationship between kVA, voltage, and current.

First, we start with the apparent power in kVA, which can be converted to amps using the formula:

[ \text{Amps} = \frac{\text{kVA} \times 1000}{\sqrt{3} \times \text{Voltage}} ]

For the 45 kVA transformer, the voltage is 208 volts (line-to-line voltage).

Calculating the total available current for the transformer:

[ \text{Amps} = \frac{45 \times 1000}{\sqrt{3} \times 208} ]

Calculating this gives:

[ \text{Amps} ≈ \frac{45000}{360.64} ≈ 124.84 \text{ amps} ]

This total current of approximately 124.84 amps represents the maximum load that the transformer can handle across all three phases.

Since it is a 3-phase system, the load is distributed among the