During a renovation of a commercial kitchen, an electrician needs to replace an old single-phase, 240 V, 5 kW electric convection oven. The existing circuit uses 10 AWG copper conductors, and the overcurrent device is a 30 A breaker. Assuming the new oven also requires 5 kW, 240 V, single-phase, and considering the ambient temperature of 30 °C (86 °F), what is the maximum allowable continuous load current permitted on this branch circuit, based on standard CEC interpretation?

Question: During a renovation of a commercial kitchen, an electrician needs to replace an old single-phase, 240 V, 5 kW electric convection oven. The existing circuit uses 10 AWG copper conductors, and the overcurrent device is a 30 A breaker. Assuming the new oven also requires 5 kW, 240 V, single-phase, and considering the ambient temperature of 30 °C (86 °F), what is the maximum allowable continuous load current permitted on this branch circuit, based on standard CEC interpretation?

Answer options: ✅ 24 A

• 30 A
• 40 A
• 50 A

Correct answer: 24 A

Explanation: For resistive loads like ovens, the continuous load is typically limited to 80% of the overcurrent device rating. Rule 8-104(2) states that the maximum continuous load shall not exceed 80% of the rating of the overcurrent device where the load is continuous. Therefore, 0.80 x 30 A = 24 A. The ampacity of the 10 AWG conductor (rated 30 A for 90 °C) is sufficient, but the breaker limits the continuous load.