If a utility just invited you to sit an EEI test and you are not sure what that means, you are in the right place. The EEI test is not a single exam — it is a family of pre-employment aptitude batteries built by the Edison Electric Institute (EEI) and used by U.S. investor-owned electric utilities to screen candidates for line, plant, and technical jobs. The four you are most likely to face are the CAST™, MASS™, POSS™, and TECH™ batteries, and the single most important thing to sort out before you study is which one your employer actually uses. This guide explains what the EEI test is, compares the four main batteries side by side, shows you how to identify your battery from your job role, breaks down the sections and timing, walks through worked sample questions, and explains the 1–10 scoring so you know what a good result looks like.
CAST™, MASS™, POSS™, and TECH™ are property of the Edison Electric Institute (EEI), which is not affiliated with and does not endorse this site.
What Is the EEI Test?
The EEI test is a set of standardized, job-related selection tests developed by the Edison Electric Institute, the trade association that represents America’s investor-owned electric utilities. Rather than each utility writing its own hiring exam, EEI built a shared library of validated aptitude “batteries,” each aimed at a specific family of utility jobs. When a power company posts a lineworker, plant-operator, or technician opening, it typically administers one of these EEI batteries as an early screen.
Who develops it: the Edison Electric Institute (EEI)
EEI is a Washington-based industry association, not a testing storefront you can walk into. Its selection tests were built and statistically validated so that scores predict on-the-job performance for the roles they target. That validation is why so many utilities trust them: the batteries are defensible, standardized, and tied to real job requirements.
Why utilities use EEI batteries
Utility work is expensive to train and unforgiving of mistakes, so employers want an objective measure of whether a candidate can handle mechanical reasoning, arithmetic under time pressure, reading technical material, and spatial or diagnostic thinking. A validated aptitude battery gives them a consistent, legally defensible way to compare applicants before spending money on interviews, background checks, and apprenticeship training.
Important: EEI builds the tests, but individual utilities administer them
EEI is the developer of these tests, not your employer. The individual utility — FirstEnergy, TVA, PSEG, CenterPoint, or whoever invited you — administers the test, decides which battery applies to the job, and sets its own hiring threshold. “EEI” is not the company you are applying to, and there is no single, universal “EEI passing score.”
The Four Main EEI Tests: CAST vs MASS vs POSS vs TECH
Most utility candidates sit one of four EEI batteries. They share a common core — math, mechanical reasoning, and reading — but each targets a different job family and swaps in a distinct fourth or specialty section. Here is the head-to-head comparison that competitors usually split across four separate pages:
| Test | Questions / Time | Who takes it | Distinctive section |
|---|---|---|---|
| CAST | 110 Q / ~87 min | Construction & skilled trades (lineworkers, T&D) | Graphic Arithmetic |
| MASS | 118 Q / ~72 min | Power-plant maintenance craft (mechanics, welders) | Assembling Objects |
| POSS | 146 Q / ~2.5 hr | Power-plant & control-room operators | Figural Reasoning |
| TECH | 91 Q / ~65 min | Associate-degree technical roles | Graphic Problem Solving, Interpreting Diagrams, Reasoning from Rules |
CAST — Construction & Skilled Trades Selection System
CAST is the flagship for construction and transmission & distribution (T&D) roles — apprentice lineworkers, groundmen, and skilled-trades hires. Its four sections are Graphic Arithmetic (16 Q / 30 min), Mathematical Usage (18 Q / 7 min), Mechanical Concepts (44 Q / 20 min), and Reading for Comprehension (32 Q / 30 min), for 110 questions in roughly 87 minutes. Because line and construction work leans on print reading, CAST is the only battery that uses Graphic Arithmetic — arithmetic worked off a dimensioned drawing. See our full CAST test guide.
MASS — Plant Maintenance Selection System
MASS screens power-plant maintenance craft — mechanics, machinists, welders, and pipefitters. It runs about 118 questions in roughly 72 minutes and combines mechanical concepts, reading, math, and an Assembling Objects section that tests how well you can visualize how separate parts fit together. More detail in our MASS test guide.
POSS — Plant Operator Selection System
POSS is the longest of the four — about 146 questions in roughly 2.5 hours — and it screens control-room and power-plant operators, the people who monitor and run generating equipment. Alongside the shared core it includes a Figural Reasoning section that measures pattern-recognition and abstract diagnostic thinking. See our POSS test guide.
MASS and POSS share the same reading, math, and mechanical core. The practical difference candidates fixate on is the specialty section: MASS uses Assembling Objects (hands-on spatial fit) while POSS uses Figural Reasoning (abstract pattern logic). If you know your role — maintenance craft vs. control-room operator — you know which one you’ll see.
TECH — Technician Occupations Selection System
TECH is aimed at associate-degree technical occupations — lab, telecom, drafting, and estimating roles. It is shorter (about 91 questions in roughly 65 minutes) but broader in question type, adding Graphic Problem Solving, Interpreting Diagrams, and Reasoning from Rules on top of the math and reading core.
SASS, SO/PDII, MRAB, and CSR — the other EEI batteries in brief
Beyond the big four, EEI publishes several specialty batteries. SASS screens administrative and support staff; SO/PDII (System Operator / Power Dispatching) targets dispatchers and control-center operators; MRAB (Meter Reader Aptitude Battery) is used for metering roles; and CSR covers customer-service representatives. If your invitation names one of these, the study emphasis shifts — but the pace-and-accuracy habits below still apply.
CAST-style timed simulations plus every section you’ll face on CAST, MASS & POSS
- Full CAST-style battery plus a Mathematical Usage speed drill — practice the exact sections and time limits
- 1,200+ practice questions — every answer explained step by step
- All timed simulations: CAST-style, Bennett-style, Ramsay-style, Wiesen-style, EIAT, IBEW, ASVAB
- 10 topic drills (graphic arithmetic, mechanical concepts, circuits, spatial…) with instant explanations
$67 one-time · 365-day access · instant online access
Not affiliated with or endorsed by the Edison Electric Institute. Unofficial practice material — original simulated questions only.
Which EEI Test Am I Taking?
This is the number-one point of confusion, and it has a simple answer: your job role determines your battery. Find the row that matches the position you applied for.
| Your role | Likely EEI battery |
|---|---|
| Lineworker, T&D, construction, skilled trades | CAST |
| Plant maintenance craft — mechanic, machinist, welder, pipefitter | MASS |
| Power-plant / control-room operator | POSS |
| Associate-degree technical — lab, telecom, drafter, estimator | TECH |
| Administrative / clerical support | SASS |
| Dispatcher / system operator / control center | SO/PDII |
What to do if your employer hasn’t told you
Do not guess from the role name alone — confirm it. Re-read your invitation email and the job posting; the battery name (CAST, MASS, POSS, TECH) is often stated outright or named in the test-scheduling link. If it isn’t, email the utility’s HR or recruiting contact and ask directly: “Which EEI battery will I be taking?” Utilities answer this routinely. Until you have that confirmation, the safest prep is to drill the shared core — math, mechanical concepts, and reading — because every battery includes it.
EEI Test Format, Sections & Timing
All EEI batteries are timed, multiple-choice, and mostly computer-based. The batteries mix and match from a common pool of section types. Here is what each one measures:
- Graphic Arithmetic — arithmetic worked off a dimensioned drawing; you read numbers off a print and compute a missing value (CAST).
- Mathematical Usage — fast unit conversions and formula-style arithmetic under heavy time pressure.
- Mechanical Concepts — pictorial physics: gears, levers, pulleys, force, and motion shown as diagrams.
- Reading for Comprehension — pulling facts and conclusions from technical passages.
- Specialty sections — Assembling Objects (MASS), Figural Reasoning (POSS), and Interpreting Diagrams / Reasoning from Rules (TECH).
Timing is where CAST candidates get caught out. The section totals below turn into brutally short per-question windows — the make-or-break speed sections are flagged in red:
| CAST section | Questions | Time | Per question |
|---|---|---|---|
| Graphic Arithmetic | 16 | 30 min | ~113 s |
| Mathematical Usage | 18 | 7 min | ~23 s |
| Mechanical Concepts | 44 | 20 min | ~27 s |
| Reading for Comprehension | 32 | 30 min | ~56 s |
Mechanical Concepts is the single largest block on CAST — 44 of the 110 questions — so it deserves the most drill time. For reference, the other batteries run to different totals: MASS is about 118 questions in ~72 minutes, POSS about 146 questions in ~2.5 hours, and TECH about 91 questions in ~65 minutes.
Mathematical Usage (~23 s/question) and Mechanical Concepts (~27 s/question) are speed sections, not accuracy sections. Practice pacing against a clock, not just getting the right answer with unlimited time — on the real test, hesitation is what sinks people.
EEI Test Sample Questions (With Worked Solutions)
Below are three simulated questions in the style of the EEI batteries — one for each of the visual sections that give candidates the most trouble. These are original, simulated / style questions — not actual test content. Try each before opening the explanation.
The dimensioned drawing shows a steel bracket plate 7 3/4 in. tall. A rectangular notch is cut from the upper-right corner, and the right edge remaining below the notch measures 5 1/2 in. What is the depth of the notch, measured vertically down from the top edge?
A. 1 3/4 in. B. 2 in. C. 2 1/4 in. D. 2 3/4 in.
Show the answer & how to get it
Answer: C. The overall plate height is 7 3/4 in., and the right edge remaining below the notch is 5 1/2 in. The notch depth is the difference: 7 3/4 − 5 1/2 = 2 1/4 in. On dimensioned drawings, a missing dimension is almost always found by subtracting a labeled partial dimension from an overall one — never by eyeballing the picture.
A loading dock stands 4 ft above the pavement. Ramp X is 8 ft long and Ramp Y is 16 ft long, and each reaches from the pavement to the top of the dock. Ignoring friction, rolling a heavy drum up which ramp takes less force?
A. Ramp X (8 ft long) B. Ramp Y (16 ft long) C. Both ramps take the same force
Show the answer & how to get it
Answer: B. Both ramps lift the drum the same 4 ft, so the total work is the same either way — but the longer ramp spreads that work over twice the distance. A gentler slope means less force at any moment, in exchange for pushing farther. Trading distance for force is the whole point of an inclined plane.
Two circuits use identical batteries and identical bulbs. In circuit 1, two bulbs are wired in series in a single loop. In circuit 2, two bulbs are wired in parallel, each on its own branch across the battery. In which circuit do the bulbs glow brighter?
A. The bulbs in circuit 1 (series) B. The bulbs in circuit 2 (parallel) C. The bulbs glow equally in both circuits
Show the answer & how to get it
Answer: B. Each bulb wired in parallel connects directly across the battery, so it receives the battery’s full voltage. The two series bulbs must share that same voltage, so each gets only about half. More voltage across a bulb drives more current through it — so the parallel bulbs glow brighter.
Want more? Start with the free, no-email mechanical aptitude practice test, then drill the exact section types on the electrical aptitude test and mechanical comprehension pages.
How the EEI Test Is Scored
The 1-to-10 index score explained
EEI batteries report results as a single index score on a 1–10 scale, combined across the test’s sections. A higher number reflects a higher predicted probability of success on the job, with 10 representing the strongest predicted fit. You are not scored per section in the report you or the employer sees — the sections roll up into one overall index.
Is there a passing score?
There is no single universal pass mark. EEI supplies the validated test and the 1–10 index, but each utility sets its own hiring threshold based on the role and its applicant pool. In practice, candidates are usually told only pass/fail or “you may proceed,” without a section-by-section breakdown. Because thresholds are employer-set, a score that clears one utility’s bar may not clear another’s — the realistic goal is to land in the upper part of the scale rather than to hit one magic number.
No penalty for wrong answers
EEI batteries do not subtract points for wrong answers, so a blank scores the same as a wrong guess: zero. That has a direct consequence for strategy — covered in the next section.
How Hard Is the EEI Test?
The EEI test is challenging mainly because of speed, not because the individual questions are exotic. The content — arithmetic, mechanical reasoning, reading, and (depending on the battery) spatial or diagnostic thinking — is the kind you can prepare for. What separates candidates is whether they can do it fast enough. Mathematical Usage gives you roughly 23 seconds per item and Mechanical Concepts about 27 seconds; if you have to stop and think from scratch on each one, you will run out of time before you run out of questions.
Always guess — never leave a blank
Because there is no penalty for wrong answers, leaving a question blank is strictly worse than guessing. Before any section timer runs out, fill in an answer for every remaining item. On a multiple-choice question, even a blind guess has real odds of being right, and a lucky guess counts exactly the same as a carefully worked one. Pace yourself by the clock, mark and skip anything that is eating your time, and sweep back to guess on the leftovers before the section ends.
There is no wrong-answer penalty — so never leave a blank. Guess before the timer ends, and don’t burn a full minute on one hard item when three easy ones are waiting behind it.
How to Prepare for the EEI Test
A focused four-step plan beats scattered practice. Work through it in order:
CAST-style battery, section speed drills, and every other major aptitude test
- Graphic Arithmetic, Mechanical Concepts, Math Usage & Reading drills in the same format and time limits
- 1,200+ practice questions — every answer explained step by step
- 12+ full-length timed simulations across CAST, Bennett, Ramsay, Wiesen, EIAT, IBEW & ASVAB
- 10 topic drills (gears, pulleys, levers, circuits…) with instant explanations
$67 one-time · 365-day access · instant online access
Not affiliated with or endorsed by the Edison Electric Institute. Unofficial practice material — original simulated questions only.
EEI Test — Compare It to Related Aptitude Tests
The EEI batteries sit inside the wider utility and electrical aptitude family. If you are applying broadly, you may also encounter these:
| Test | Focus | Who uses it |
|---|---|---|
| Electrical aptitude test | Math, reading & electrical reasoning | Electrical trades broadly |
| IBEW aptitude test | Algebra/functions + reading (no mechanical) | IBEW / Electrical Training Alliance apprenticeships |
| Mechanical comprehension test | Pictorial mechanical reasoning | Manufacturing, trades, utilities |
| Mechanical aptitude practice test | All-access prep across every battery | Any mechanical/utility candidate |
EEI Test FAQ
What is the EEI test and who uses it?
The EEI test is a family of pre-employment aptitude batteries developed by the Edison Electric Institute (EEI) and used by U.S. investor-owned electric utilities to screen candidates for line, plant, technical, and support roles. The main batteries are CAST, MASS, POSS, and TECH. EEI develops and validates the tests; individual utilities administer them and set their own hiring thresholds.
What is the difference between the CAST, MASS, POSS, and TECH tests?
They target different job families and swap in different specialty sections. CAST (about 110 questions in ~87 minutes) is for construction and skilled trades and uses Graphic Arithmetic. MASS (~118 questions, ~72 minutes) is for plant maintenance craft and uses Assembling Objects. POSS (~146 questions, ~2.5 hours) is for plant operators and uses Figural Reasoning. TECH (~91 questions, ~65 minutes) is for associate-degree technical roles and adds Graphic Problem Solving, Interpreting Diagrams, and Reasoning from Rules. MASS and POSS are nearly identical except for that specialty section.
How is the EEI test scored, and what score do you need to pass?
Results are reported as a single index score on a 1–10 scale, combined across the sections, where a higher number reflects a higher predicted probability of job success. There is no universal pass mark — each utility sets its own threshold for the role, and you are typically told only pass/fail without a section breakdown. Many utilities look for candidates in the upper part of the scale, but the exact cutoff varies by employer.
How many questions are on the EEI test and how long does it take?
It depends on the battery. CAST has about 110 questions and takes roughly 87 minutes; MASS about 118 questions in ~72 minutes; POSS about 146 questions in ~2.5 hours; and TECH about 91 questions in ~65 minutes. Each battery is broken into timed sections, and some sections give you only around 23–27 seconds per question.
Is the EEI test hard, and is there a penalty for wrong answers?
The main difficulty is speed rather than exotic content — the Mathematical Usage and Mechanical Concepts sections are especially fast-paced. There is no penalty for wrong answers, so you should never leave a question blank; always guess before the section timer runs out, since a lucky guess counts the same as a worked answer.
How can I practice for the EEI test for free?
Start with our free, no-email mechanical aptitude practice test to see the question styles and gauge your baseline, then drill the specific section types on the mechanical comprehension and electrical aptitude pages. When you’re ready for full-length, timed CAST-style batteries with worked explanations, the all-access bundle covers every EEI section plus the other major utility and trades tests.
Ready to walk in prepared?
Try the free practice test first — no email required.
CAST™, MASS™, POSS™, and TECH™ are property of the Edison Electric Institute (EEI), which is not affiliated with and does not endorse this site. All practice material is original and simulated. See our full disclaimer.