Power Grid Operator Exam Prep · iPhone, iPad & Mac

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An independent trainer for the four NERC System Operator Certification examinations: Reliability Coordinator (RC); Balancing, Interchange and Transmission (BT); Transmission Operator (TO); and Balancing and Interchange (BI).

Requirements

iPhone or iPad running iOS 26.0 or later, or a Mac running macOS 26.0 or later. Studying works entirely offline; the App Store is contacted only for the optional Full Access purchase, and iCloud only to sync your progress. It appears as “Grid Prep” under its icon; before version 1.1 it was called System Operator Prep.

One bank, four credentials

All four examinations are drawn from the same six content domains and the same 31 knowledge areas. What differs is only how many scored questions each area contributes, and NERC publishes that table for every credential. So the app carries one question bank and one progress record: picking a credential re-weights your readiness estimate, the order of your weak areas, and the way a mock paper is sampled. An answer counts towards all four.

Why the score is a count and not a percentage

NERC passes candidates on an absolute cut score — 92 of 120 for RC and BT, 76 of 100 for TO and BI — so the app shows a projected score out of the paper, and ranks knowledge areas by how many scored questions they are costing you on the credential you picked.

Full Access and restoring a purchase

The app is free to try: 50 practice questions in any mode — the knowledge areas, Smart Review and every generated trainer — one full mock paper on any credential, and the whole Library. Full Access is a single one-time in-app purchase — no subscription — that unlocks every question, unlimited mock papers on all four credentials and every trainer, on your iPhone, iPad and Mac. It follows your Apple Account: on another device it unlocks by itself, or tap Restore purchases in Library › About. Downloaded the app before version 1.2? You keep everything, free.

Answering a question

Tap an option to choose it — change your mind if you like — then Confirm answer to see whether it was right, with the explanation and its reference. On a keyboard, A–D or 1–4 choose an option and Return confirms it, then moves to the next question.

Progress and resetting

From version 1.4 your iPhone, iPad and Mac combine their progress through your own iCloud account: answers add up, the review schedule carries on from your latest answer, and mock papers and simulator runs from every device appear together. Sign in to iCloud on each device; the switch is in Library › Sync, and it is on unless you turn it off. Every device still keeps its own copy, so studying works offline and catches up when you are back online. The free allowance (50 questions, one mock paper, one simulator run) is shared by your synced devices. To start over, use "Reset all progress" at the bottom of the Library tab: with sync on it erases progress on every device, with sync off on that device only.

A question looks wrong?

Every question carries an explanation and a reference. If you believe an answer conflicts with the currently enforceable standard, email the question text and your reference — verified corrections ship in the next update. Reliability Standards are revised regularly: always treat the current enforceable standard at nerc.com, and your own entity's operating procedures, as authoritative.