| Mistake | Consequence | Solution | | :--- | :--- | :--- | | Ignoring temperature correction | Undersized wires | Use NEC Table 310.15(B)(2)(a) in your PDF | | Forgetting continuous load (125% rule) | Breaker trips at 80% load | Multiply motor/lighting loads by 1.25 | | Using one-line distance for voltage drop | Underestimates drop | Use round-trip distance (2L for single phase) | | Confusing kVA and kW | Wrong capacitor sizing | Always use kVA for transformer calculations | | No spare capacity in load calc | Panel overload in 2 years | Add 20% future expansion factor |