- CAST is 110 questions across four timed tests totaling 87 minutes, not one long exam.
- Mechanical Concepts carries 44 items (40%) - the single biggest scoring opportunity.
- EEI sets no universal passing score; each hiring utility sets its own cutoff.
- There is normally no candidate fee - the employer invites you and pays for testing.
Exam Snapshot: The Numbers That Matter
The Construction and Skilled Trades Selection System (CAST) is owned and published by the Edison Electric Institute (EEI) and used by investor-owned electric utilities to screen candidates for skilled trades roles. Unlike open-registration certification exams, CAST is administered directly by the hiring utility - there's no public testing calendar and normally no fee to the candidate, because the employer invites qualified applicants and covers the cost of testing.
Before you dive into any prep, memorize this table. It's the entire architecture of the exam in one glance.
| Section | Items | Time | Weight |
|---|---|---|---|
| Graphic Arithmetic | 16 | 30 min | 15% |
| Mathematical Usage | 18 | 7 min | 16% |
| Mechanical Concepts | 44 | 20 min | 40% |
| Reading for Comprehension | 32 | 30 min | 29% |
Total: 110 multiple-choice questions, 87 minutes of actual testing time, inside a session of roughly two hours once check-in and instructions are included. There is no penalty for guessing, so every question deserves an answer before time runs out. For a deeper walkthrough of each section, see the CAST Exam Domains 2026 guide.
The Four Domains at a Glance
Each domain measures a distinct aptitude, and utilities weight the composite index score (1-10) based on the job family you're being considered for - transmission and distribution, facilities and repair, other facilities, electrical repair, machining and vehicle repair, or meter service and repair.
Graphic Arithmetic (16 items, 30 minutes)
Tests your ability to read charts, graphs, and tables, then perform arithmetic using the data you extract.
- Practice reading bar graphs and tables quickly under time pressure
- Basic arithmetic fluency matters more than advanced math
Mathematical Usage (18 items, 7 minutes)
The shortest, fastest section - straightforward math problems with almost no time to think.
- Speed and automatic recall of arithmetic rules beat careful long division
- Only appears on the original CAST, not CAST-R
Mechanical Concepts (44 items, 20 minutes)
The largest section by far - mechanical reasoning involving gears, pulleys, levers, hydraulics, and basic circuits.
- About 27 seconds per item, so pattern recognition beats slow derivation
- Highest single-section payoff for study time invested
Reading for Comprehension (32 items, 30 minutes)
Passages followed by questions testing whether you understood technical or procedural text accurately.
- Practice skimming for main idea, then scanning back for detail
- Common in utility manuals, safety procedures, and work orders
For a full breakdown of question types and sample logic within each area, the CAST Study Guide 2026 walks through practice strategies section by section.
Format, Registration, and Scoring Mechanics
CAST doesn't work like a typical open-enrollment certification exam, and that trips up a lot of first-time candidates. A few mechanics worth memorizing:
- No open registration: the hiring utility invites you after you apply to a qualifying job posting.
- No standard fee: the employer typically pays for administration, so there's usually no candidate cost - details vary by employer, and you can compare scenarios in the CAST Certification Cost breakdown.
- No universal passing score: EEI does not publish one cutoff. Each utility sets its own minimum index score per job family, which is why you won't find a single "passing number" online - see CAST Passing Score 2026 for how to think about this.
- No academic prerequisites: beyond being an invited applicant, there's no degree or certification requirement. Full detail is in CAST Requirements 2026.
- No national pass rate: because cutoffs vary by employer and job family, there's no single published pass rate - context on why is in CAST Pass Rate 2026.
Key Takeaway
Don't search for "the CAST passing score" as if it's one fixed number - it varies by utility and job family. Focus your energy on maximizing your raw performance in each domain instead.
Mechanical Concepts: Your Highest-Leverage Section
With 44 of 110 questions - roughly 40% of the entire exam - Mechanical Concepts deserves more study time than the other three domains combined. At about 27 seconds per item, you need pattern recognition, not slow first-principles derivation.
Core topics that show up repeatedly:
- Gear trains and rotational direction/speed relationships
- Pulley systems and mechanical advantage
- Levers and simple machines (fulcrum position, force multipliers)
- Basic hydraulics (pressure, flow, force transfer)
- Basic electrical circuits (series vs. parallel, simple current logic)
If you're still deciding how much overall prep time this exam warrants, How Hard Is the CAST Exam? breaks down the difficulty profile section by section.
One-Week Quick Review Plan
If your test date is close, prioritize by weight and time pressure rather than trying to cover everything equally.
Mechanical Concepts
- Drill gears, pulleys, levers, and hydraulics diagrams daily
- Time yourself at roughly 27 seconds per question
Reading for Comprehension
- Practice technical passages with a strict 30-minute cap
- Focus on skim-then-scan technique for detail questions
Graphic Arithmetic
- Practice reading charts/tables fast under a 30-minute limit
- Combine data extraction with basic arithmetic drills
Mathematical Usage
- Speed drills only - 18 items in 7 minutes leaves no room to hesitate
- Skip this section entirely if you're prepping for CAST-R
Full Review
- Take a full-length timed practice run on the main practice test site
- Revisit weak areas identified during the run
For a more thorough multi-week plan rather than this compressed version, see the CAST Study Guide 2026.
CAST vs. CAST-R
Two versions of this exam circulate today: the original CAST (2001) and the newer CAST-R (2020). Know which one your invited assessment uses before you prep.
| Feature | Original CAST (2001) | CAST-R (2020) |
|---|---|---|
| Mathematical Usage section | Included (18 items, 7 min) | Replaced |
| Work Preferences Inventory | Not included | 105 items, 30 minutes |
| Mechanical Concepts | Included (44 items) | Included (44 items) |
| Reading for Comprehension | Included (32 items) | Included (32 items) |
The Work Preferences Inventory in CAST-R measures preferred work style and environment rather than aptitude - there's no "right answer" to study for, unlike the timed cognitive sections. If you're not sure which version your utility uses, ask your recruiter directly; it changes how you should allocate prep time.
Retest Rules and Score Validity
Because CAST is employer-administered, retest policy isn't uniform - but common patterns exist:
- A minimum of 30 days is typically required between a first and second attempt
- Many utilities cap candidates at two attempts per 12-month period
- A qualifying score generally stays on file with that utility for future postings until job requirements or the test itself changes
This matters for planning: if you don't clear a given utility's internal cutoff on your first try, you're not necessarily locked out of that career path - you may just need to wait out the retest window. For how this affects long-term career value, see Is the CAST Certification Worth It? and the CAST Salary Guide 2026 for the roles this screening supports.
If any of the terminology in this article is unfamiliar, start with the fundamentals in What Is CAST? or CAST Meaning before working through the domain-specific sections above. For structured practice matched to the real 87-minute format, run a full timed set on our practice platform.
FAQ
110 multiple-choice questions total, split across four separately timed tests: Graphic Arithmetic (16), Mathematical Usage (18), Mechanical Concepts (44), and Reading for Comprehension (32).
Normally no. The hiring investor-owned utility invites qualified applicants and pays for the testing session; there is no open public registration or standard candidate fee.
There isn't one universal passing score. EEI publishes no national cutoff or pass rate - each utility sets its own minimum index score (on a 1-10 scale) for each job family.
Mechanical Concepts, since it makes up 44 of 110 questions - about 40% of the exam - covering gears, pulleys, levers, hydraulics, and basic circuits.
CAST-R (2020) replaces the Mathematical Usage section with a 105-item, 30-minute Work Preferences Inventory that measures work style rather than aptitude; the original CAST (2001) keeps Mathematical Usage instead.