The questions that sink people on the SP-PH exam are the calculations — box fill, motor sizing, load calcs. Each lesson below walks a real problem step by step, showing the NEC table or rule used at every line so you can repeat it on exam day.
Count conductors, devices, clamps, and grounds; pick a box that's big enough. Table 314.16.
FLC tables, 125% conductors, overload, branch protection, and disconnect. Article 430.
Standard service calculation from square footage to service amps. Article 220.
Table 310.16, the 60/75/90°C termination rule, ambient and bundling adjustments.
V=IR, power, and the voltage-drop formula with a worked branch-circuit example.
The practice exam has dedicated calculation questions in every topic.
Go to the Practice Exam →