4 questions · 8% of the Calculations exam
Why C is correct
Motor overload protection uses nameplate current for this calculation. Multiplying 32 amperes by the supplied 1.15 factor gives 36.8 amperes; this is distinct from branch-circuit conductor sizing.
Where to look it up
https://www.elightinformation.com/post/motor-and-welding-machine-calculation-steps-2026-nec
Why D is correct
28 A × 125% = 35 A, D. This establishes the conductor-ampacity floor for the stated motor case. It does not select an AWG size or an overload setting; final conductor selection must also meet installation and terminal limits. Source: E Light Electric, Motor and Welding Machine Calculation Steps 2026 NEC, motor-circuit selection section: https://www.elightinformation.com/post/motor-and-welding-machine-calculation-steps-2026-nec
Why C is correct
Reverse the conductor factor: 52.5 ÷ 1.25 = 42 amperes of table full-load current. Keep units consistent and use only the factors stated; no optional method or unstated demand factor is assumed.
Why D is correct
Divide the setting by the supplied factor: 31.05 ÷ 1.15 = 27 amperes nameplate current. Keep units consistent and use only the factors stated; no optional method or unstated demand factor is assumed.
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