🔍 Key Concepts

• Compare the breaker trip settings (AT) and frame ratings (AF) for each feeder in the group control center. • Relate motor/load size (HP or kW) to expected full‑load current and required conductor ampacity. • Remember that a smaller required ampacity allows a smaller conductor cross‑sectional area for the same insulation type and installation.

💭 Think About

• Which piece of equipment is protected by the lowest ampere trip (AT) overcurrent device in the illustration? How does that affect the minimum cable size? • Look at the HP or kW rating shown in the circles at the bottom. Rank the loads by size, then match them to the breaker ratings above. Which combination would logically need the smallest current‑carrying capacity? • Is there any feeder where both the load rating and the breaker trip setting are clearly lower than the others? What does that say about the conductor size?

✅ Before You Answer

• Verify which label at the top (e.g., 75AT/100AF, 150AT/225AF, 60AT/100AF, 40AT/100AF) corresponds to each specific load at the bottom. • Confirm that all feeders are shown as three‑conductor cables, so the only difference is the individual conductor cross‑sectional area (ampacity), not the number of conductors. • Double‑check that you are choosing the load with the smallest protective device ampere trip (AT) and the smallest power rating (HP or kW) before selecting your answer.