Plant Operator Selection System (POSS) Test

The Plant Operator Selection System (POSS) test consists of four timed aptitude tests, commonly referred to as a test battery, put together by the Edison Electric Institute (EEI), which is representative of most American electric companies. The test helps electric companies identify capable candidates for operating positions within nuclear, hydropower, and fossil fuel power plants. The test typically lasts two hours.

Job titles pertaining to this type of position may vary; however, either the job
advertisement or your potential employer will inform you if you need to take
the POSS test.

Online POSS Prep Course

If you want to be fully prepared, Mometrix offers an online POSS Prep Course. The course is designed to provide you with any and every resource you might want while studying. The POSS Course includes:

  • Review Lessons Covering Every Topic
  • 750+ POSS Practice Questions
  • Over 20 Instructional Videos
  • Money-back Guarantee
  • Free Mobile Access
  • and More!

The POSS Prep Course is designed to help any learner get everything they need to prepare for their POSS exam. Click below to check it out!

A man sits at a desk using a laptop. The text beside him reads,

What is
on the POSS Test?

Each of the tests that make up the POSS evaluate different areas of knowledge plant
operators will be expected to have in order to perform their jobs successfully.

Because each test has a different number of questions, their time limits will be


Questions: 36 multiple-choice

Time limit: 30 minutes

Reading comprehension refers to an individual’s ability to interpret and understand a written
work. For plant operators, this applies to understanding any manuals or
training that will appear in the workplace.  

For this test, you will read several passages and answer multiple-choice questions
that follow after each one.

Mechanical Concepts

Questions: 44 multiple-choice

Time limit: 20 minutes

For the Mechanical Concepts test, you will be evaluated on your understanding of
physics within mechanical processes. The processes discussed will be similar to
those you will experience in the workplace.

Each question will have an image either of a piece of machinery with labels
describing the different parts that are shown or of a typical mechanical
procedure you may witness. Each question will have three possible answers to
choose from.

Mathematical Usage

There are two versions of the Mathematical Usage test. Both evaluate different areas
and, for that reason, have a different time limit and number of questions.

Version One

Questions: 18 multiple-choice

Time limit: 7 minutes

The first version of the Mathematical Usage test is meant to gauge your ability to
use basic math formulas. These formulas will be provided at the start of the
test. Each question will be followed by several possible answers.

Version Two

Questions: 46 multiple-choice

Time limit: 17 minutes

The second version of the Mathematical Usage test gauges how well you solve
equations for three different types of math problems:

  • Algebra problems
  • Formula conversion problems
  • Word problems

Each type will appear in its own section (i.e. all algebra problems will be grouped
together followed by a group of word problems). As with the other version of
the Mathematical Usage test, you will be provided with a math problem, and all
possible answers will appear beneath it.

Figural Reasoning

Questions: 20 multiple-choice

Time limit: 10 minutes

The Figural Reasoning test measures your ability to solve problems by identifying
patterns. Three types of questions will appear in this test:

Picture Series

With Picture Series questions, you will be provided with four images that create a
series and will then need to select the next image necessary for maintaining
the existing pattern.

Picture Comparison

For Picture Comparison questions, three images will form a square with a question
mark replacing the missing image. You will be required to identify the pattern
between the first two images in order to determine which image from the choices
you are given belongs in the empty space.

Picture Progression

Picture Progression questions will have several rows of images that form patterns
horizontally and vertically. One space, as with the Picture Series and Picture
Comparison questions, will have a question mark standing in for the image that
will complete the missing pattern.

Can I Use a Calculator?

The POSS test prohibits the use of electronic devices such as calculators, cell phones, or MP3 players.

How is the Test Graded?

The number of questions you get right on the POSS will determine your overall score. The score is determined by taking the individual sections’ scores and combining them so they may be evaluated on a scoring scale of 0 to 15 with 15 indicating a candidate’s high probability of success in the workplace. Keep in mind that you will not lose points for wrong or unanswered questions.

Can Other Electrical Companies Use My Score?

While some applicants have found that other electrical companies could access their POSS score from previous employment, this is not always the case. It is best to prepare for the POSS whenever applying to a plant operating position with another electric company as companies may rely on different versions of the POSS or have different considerations regarding a passing score.

Where and When Can I Take the POSS Test?

The POSS test cannot be taken at any time like other tests, such as the Civil Service exam or the GED test. POSS testing is only available through an electric company with a job opening for an operating position. This is because the POSS is part of a company’s hiring process and measures each candidate’s abilities.

The company you are applying to will have a date and time pre-selected for the test.

How Much Does it Cost to Take the POSS Test?

Because the POSS test is offered as part of the hiring process for plant operator positions within electric companies, there is no fee.

How Can I Prepare for the POSS Test?

That’s a great question.  We’ve broken down the answer into three parts.

  1. Do yourself a favor and study.  Do not walk in unprepared. We have recommended prep materials below, but that only helps if you actually try.  Plus, studying is actually proven to be the best antidote to test anxiety.
  2. Take care of yourself.  Make sure you’re eating well, exercising, and sleeping.  All of these things are scientifically linked to brain performance.  If you take care of your body, you’ll be helping your grades.
  3. Get a study guide or set of flashcards.  Some people study better a certain way. Find your study strengths and make the most of them.  We’ve tried to make it easy for you by tracking down the best study guide for your exam.  See the link below!

Study Guide


Last Updated: March 8, 2024