The SP-PH exam is open book — which means your references aren't optional, they're your most important tool. Get the exact editions below. Buying the wrong version can cost you at the testing center.
The core reference for the technical questions. You must use the 2020 edition — older or newer editions will not match the code questions.
ISBN 978-1-4559-2297-0 NFPA 70 Softbound paperback
Covers the business, law, and project-management portion of the exam. It must be the North Carolina Electrical, 13th edition specifically — not another state or an older edition.
ISBN 978-1-948558-12-9 13th Edition NC Electrical
The licensing rules (G.S. 87, Article 4 and Title 21 NCAC 18B) are published free by the state. Don't pay for these — download and tab them.
The board lists NFPA 72 among study materials for the special-restricted exams in general, but it's primarily relevant to the fire alarm / low-voltage (SP-FALV) classification. For SP-PH it is likely not needed.
Verify with PSI / the exam handbook before buying this one — don't spend money you don't have to.