CAST test practice

What the real test usually looks like

What CAST is. The Construction and Skilled Trades Selection System is a battery of aptitude and behavioral tests sponsored by the Edison Electric Institute (EEI), built from research with 34 investor-owned electric companies. Its current version, CAST-R, is designed to predict success in six groups of jobs: transmission and distribution, facilities and repair, other facilities (such as equipment operator), electrical repair, machining and vehicle repair, and meter service and repair (EEI CAST-R brochure).

The four tests, as EEI's 2020 brochure describes them:

• Graphic Arithmetic: arithmetic problems using information from prints or drawings. Two drawings, each followed by several questions; 16 questions in 30 minutes. A calculator is permitted on this test. The examples have four numeric answers and a fifth choice.
• Mechanical Concepts: 44 multiple-choice items in 20 minutes. Each shows a mechanical situation in a picture, with a question and three possible answers.
• Reading for Comprehension: four passages, each followed by several multiple-choice questions; 32 items in 30 minutes.
• Work Preferences Inventory: 105 statements about your preferred work style, answered from strongly agree to strongly disagree, in 30 minutes.

The session. The brochure says CAST-R takes about two hours. Ameren describes the battery as four timed tests taken on paper in a classroom, about two and a half hours with one ten-minute break, with instructions and sample problems read aloud before each test and "speed and accuracy" equally important (Ameren). Your employer's notice says how yours will run.

What our mocks cover. Our full mocks are 92 questions in 80 minutes, in the same order as the three aptitude tests: graphic arithmetic (16 questions, each giving a part's dimensions, with four numbers then "None of these"), mechanical concepts (44 questions with A, B and "There is no difference", or a direction to choose) and reading for comprehension (32 questions on longer passages). A calculator is allowed, and you can go back and flag questions. They leave out the Work Preferences Inventory, which has no right answers to practice.

Question types with worked examples

One worked example for each kind of question, with the trap most people fall into.

1. Graphic arithmetic: lengths. A plate is 14 inches long with a hole centered 2.5 inches from each end. The distance between the hole centers is 14 - 2.5 - 2.5 = 9 inches. Trap: subtracting the edge distance only once.

2. Graphic arithmetic: areas. A 12 by 8 inch plate has a 4 by 4 inch square cut out. Its remaining area is 96 - 16 = 80 square inches. Trap: subtracting the side length (4) instead of the area (16).

3. Mechanical: balance. On a level beam, a heavier load must sit closer to the pivot than a lighter one. 60 pounds at 2 feet balances 40 pounds at 3 feet, since 120 = 120. Trap: assuming equal distances always balance.

4. Mechanical: speed and force. A small gear driving a large gear makes the large one turn slower, but with more turning force. Trap: thinking a bigger gear means more speed.

5. Mechanical: no difference. Two wheels on one axle make the same number of turns, and water pressure at the same depth is the same whatever the tank's width. Trap: avoiding "There is no difference" because it feels like a trick. Sometimes it is the answer.

6. Reading for comprehension. Answer from the passage, not from what you know about utility work. If a choice is true in real life but the passage does not say it, it is wrong here. Trap: choosing the answer that sounds most sensible instead of the one the text supports.

How to prepare

1. Read EEI's own description. The CAST-R brochure lists each test, its length and time, with example questions (EEI CAST-R brochure). If your employer gives you practice materials, use them too; Ameren's description points its applicants to EEI's practice tests (Ameren).
2. Practice reading drawings. Graphic arithmetic gives you dimensions on a part. Practice finding missing lengths, center distances, areas and inside diameters.
3. Use a calculator well. The brochure says one is permitted on graphic arithmetic. Practice with a basic calculator, and write down each step.
4. Review mechanical principles. Levers and balance, gears, pulleys, ramps, wheels and axles, and simple hydraulics and air pressure.
5. Work fast on mechanical items. 44 items in 20 minutes is under half a minute each. Learn the rules well enough to answer from the picture.
6. Read passages for detail. Note conditions, steps and reasons, and answer only from the text.
7. Practice at the real pace. Take full timed mocks, all three aptitude parts in order, so the pace feels normal on test day.

How scoring usually works

How EEI scores CAST-R. The brochure says each test is scored by the number of questions answered correctly, with no penalty for guessing or wrong answers. The test scores are then combined into an index score from 1 to 10, which is used to predict how likely a candidate is to succeed in construction and skilled trades jobs (EEI CAST-R brochure).

What that means for you. Since a wrong answer costs nothing, answer every item. The cut-off an employer uses is set by that employer; ask the company that invited you how results are shared and whether a retest is allowed.

Our practice score is the number of our own questions you answered correctly, with a breakdown by part, so you can see where to focus. It is a practice score: it is not a CAST score or index, and it does not predict whether you will pass or be selected.

Common mistakes on the CAST test

• Counting cuts or gaps wrong. Five pieces need four cuts, and a wall or edge distance often appears on both sides. Sketch it.
• Subtracting a length instead of an area. When something is cut out of a plate, subtract its area.
• Spending too long on mechanical items. The mechanical concepts test gives under half a minute per item. If you are calculating at length, step back and look for the rule.
• Mixing up speed and force. Smaller driven gears turn faster with less force; longer ramps and lever arms need less force over more distance.
• Avoiding "There is no difference". It is a real answer, not a trick.
• Reading in outside knowledge. Reading questions ask what the passage supports.
• Leaving blanks. EEI says there is no penalty for guessing, so answer everything.

A one-week CAST study plan

• Day 1: Take the free sample above. Note which part cost you the most.
• Day 2: Graphic arithmetic: lengths, center distances and inside diameters from a part's dimensions.
• Day 3: Areas, cut-outs and unit sense, with a basic calculator.
• Day 4: Mechanical concepts: levers, balance, gears and pulleys, against the clock.
• Day 5: Two or three reading passages, timed.
• Day 6: One full timed mock, all three aptitude parts in order.
• Day 7: Review every miss, then rest.