What would be the approximate power consumed by a 10 kW heat strip rated at 230V when connected to a 208V circuit?

• A. 10 kW
• B. 8.20 kW
• C. 9.00 kW
• D. 7.50 kW

Answer: (B)

To determine the power consumed by a 10 kW heat strip rated for 230V when connected to a 208V circuit, an understanding of how power relates to voltage and resistance is essential.

The power rating of the heat strip indicates its nominal performance at 230V; however, when it is supplied with a lower voltage of 208V, the power consumed will decrease. The fundamental relationship between voltage, current, and power can be represented by the equation:

[ P = V \times I ]

Where ( P ) is power, ( V ) is voltage, and ( I ) is current. Additionally, because the heat strip is essentially a resistive load, the resistance can be calculated at the rated voltage:

Given the rated power at 230V:

[ P_{\text{rated}} = \frac{V^2}{R} ]

Rearranging gives us the resistance:

[ R = \frac{V^2}{P} ]

[ R = \frac{230^2}{10000} ]

[ R = 5.29 , \Omega ]

When connected to 208V, the actual power consumed can be calculated using:

[ P_{\text{