Plant Operator Selection System (POSS Test): A Complete Guide

The Plant Operator Selection System (POSS Test) is an aptitude test widely used to evaluate an individual’s skills and abilities when applying for roles within the power sector. 

This industry requires highly skilled staff, so the POSS Test aims to assess essential skills required to perform well within the industry. Whether you want to work in nuclear, fossil fuel, or hydroelectric power plants, you will likely need to complete the POSS Test before being offered a position.

This guide is designed to tell you everything you need to know about the POSS Test so that you can be fully prepared and confident when taking the assessment for real. From information about the test and preparation strategies, to what to expect afterwards, you will find everything you need to help you practice and prepare effectively.

What Is the POSS Test?

Careers within the power plant industry can be highly demanding and require individuals with a very specific set of skills and expertise. To ensure that the best possible candidates are hired, the POSS Test was developed. 

POSS Tests are typically administered as part of a recruitment process to identify individuals who have the skills and knowledge required to work in such a demanding industry.

Whether you are applying for a role in oil, gas, nuclear, or renewable power generation, it’s likely you will be required to pass this test before being hired.

This five-part, multiple-choice assessment is administered under strictly timed conditions to assess both cognitive and practical skills such as analytical thinking, spatial awareness, and mechanical concepts. The skills and abilities evaluated by the POSS Test are deemed essential for those working as plant operators within the power plant sector.

Thorough preparation for the POSS Test can significantly improve your performance during the real assessment and enable you to achieve the required passing score.

Format and Sections of the POSS Test

The POSS Test is made up of five main sections designed to test a different area of knowledge. Each section is timed, with candidates required to answer multiple-choice questions within the time limit.

The exact time limit and number of questions will vary depending on the version of the test you are taking and the test provider. 

Reading Comprehension

This style of questioning aims to assess an individual's ability to read and interpret written information. Candidates will be shown a sample text and then asked questions relating to it. 

Good reading comprehension skills are vital for ensuring the correct interpretation of documents like safety manuals and equipment instructions.

Mathematical Usage

With questions relating to arithmetic, percentages, and basic algebra – among other mathematical concepts – the mathematical usage section of the POSS Test evaluates core knowledge. 

Having and using this knowledge is essential when it comes to monitoring plant operations and performing the type of calculations required within a plant operator role. 

Mechanical Concepts

This section aims to evaluate the basic understanding of mechanical concepts which will be used while working within a power plant. Questions will relate to topics like hydraulics, forces, and pulleys.

Spatial Ability 

An ability to visualize and manipulate objects is essential when it comes to being able to accurately interpret diagrams and manage equipment layouts. Spatial reasoning questions identify candidates who have the required level of understanding. 

Figural Reasoning 

Figural reasoning is essentially a problem-solving skill. Candidates will be asked to identify the correct image to complete a pattern or sequence. 

POSS Exam Example Questions

Reading Comprehension

Question 1:

A pump must be monitored every 3 hours to ensure it maintains optimal pressure. If pressure drops, the operator must adjust the settings to prevent equipment failure. 

According to the instructions, what should the operator do if they notice a drop in pressure?

a) Stop the machine immediately
b) Increase pressure and check again in 2 hours
c) Adjust settings to correct the pressure drop
d) Alert a supervisor about the issue 

The correct answer is: c) Adjust settings to correct the pressure drop

The instructions specify that adjusting settings is the required response to a drop in pressure.

Question 2:

While reading an equipment maintenance manual, an operator learns that routine checks are scheduled at both 10 a.m. and 3 p.m. If a problem arises between these checks, the operator must log the issue and consult the manual for troubleshooting guidance. 

What should the operator do if they notice a minor issue at 1 p.m.?

a) Wait until the next routine check at 3 p.m.
b) Log the issue and consult the manual for guidance
c) Stop the machine immediately
d) Ignore it if it is minor

The correct answer is: b) Log the issue and consult the manual for guidance

The instructions in the manual require operators to log and troubleshoot issues as they occur.

Mathematical Usage

Question 1:

An operator needs to mix a solution at a 3:1 ratio of water to chemical. 

If they need a total of 24 liters of solution, how much chemical is required?

a) 6 liters
b) 8 liters
c) 12 liters
d) 18 liters

The correct answer is: a) 6 liters

A 3:1 ratio means 3 parts water to 1 part chemical. For 24 liters total, divide by 4 (the sum of parts in the ratio), which gives 6 liters of chemical and 18 liters of water.

Question 2:

An operator checks gauges and notes that pressure is recorded at 50 PSI. If pressure drops by 20%, what is the new PSI?

a) 40 PSI
b) 42 PSI
c) 45 PSI
d) 48 PSI

The correct answer is: a) 40 PSI

A 20% decrease of 50 PSI is 10 PSI, so the new pressure is 50 – 10 = 40 PSI.

Mechanical Concepts

Question 1:

Which of the following best describes how a pulley system helps lift heavy objects?

a) It changes the direction of the force
b) It reduces the weight of the object
c) It allows a heavier load to be lifted with less force
d) It increases the weight of the object

The correct answer is: c) It allows a heavier load to be lifted with less force

Pulleys reduce the force needed to lift an object by distributing weight and changing direction.

Question 2:

If a lever has a fulcrum located closer to the load than to the effort applied, what effect does this setup have on the force needed to lift the load?

a) Increases the force required
b) Decreases the force required
c) Has no effect on the force required
d) Changes the weight of the load

The correct answer is: b) Decreases the force required

Moving the fulcrum closer to the load increases leverage, decreasing the amount of force required.

Spatial Ability

Question 1: 

A part must fit into a machine with a specific alignment. The part has three prongs that match the pattern on the machine’s opening. If the part is rotated 180 degrees, will it still fit into the opening?

a) Yes, because the prongs align symmetrically
b) No, because the prongs will misalign
c) Yes, but only if the rotation is clockwise
d) It depends on the material of the part

The correct answer is: a) Yes, because the prongs align symmetrically

If the part is symmetric around its center, a 180-degree rotation will not change alignment.

Question 2:

Two gears are connected. If Gear A has 10 teeth and Gear B has 20 teeth, how many rotations will Gear A complete for every rotation of Gear B?

a) 1
b) 2
c) 0.5
d) 4

The correct answer is: b) 2

Gear A, having half the teeth, will rotate twice for each single rotation of Gear B.

How to Prepare for the POSS Exam

As with any test, good preparation is key when it comes to performing well in the Plant Operator Selection System Test. 

Taking time to work through free POSS practice tests, study sample questions and work on any areas that might be weaker will help to boost your confidence and enable you to give your best possible performance on the day.

Study Resources

You can find a range of free POSS Test study guides, free POSS practice tests, and sample questions online, as well as paid packages. These study packs can help to identify your strengths and weaknesses. 

If you find that there is a specific section of the assessment you struggle with, you’ll also find specific guides to help – for example, mechanical reasoning guides to help with this section of the assessment. You can find a mechanical reasoning practice pack on TestHQ.

Test-Taking Strategies

You will have a strict time limit when you take the POSS Test. Because of this, it’s important to practice test-taking strategies that will enable you to answer all of the questions within the time limit. 

Working through time management strategies and taking time to focus on brushing up on weaker skills will help you to feel confident and comfortable when taking the test for real. 

Practice Exercises

POSS practice tests are one of the best things you can do to prepare for the POSS Test. These will help you to feel comfortable and familiar with the format of the test as well as the time constraints. 

Evaluating the results of POSS practice tests can also help to identify any areas of weakness that might need a little extra revision or focus during your preparations.

Stress Management

Taking tests and exams can be stressful, especially when the result can mean the difference between being offered the job you want or not. 

If you’re someone who finds tests particularly stressful, try breathing and mindfulness techniques to keep you centered. These simple methods can help you to maintain focus and recall during stressful situations.

Frequently Asked Questions

What score is needed to pass the POSS Exam?

Because the POSS Test is adapted and adjusted depending on the role and requirements of the employer, there isn’t a specific passing score. This is why it’s vital to prepare and practice as much as possible so you score as highly as you can. 

How long does the POSS Test take to complete?

The POSS Test is taken under strictly timed conditions. However, the exact time limit you will have will depend on the exact test you are taking. Different test providers will have different time limits. Typically, the test will take between 67 and 77 minutes to complete.

Can I use a calculator during the POSS Exam?

No. The use of electronic devices is prohibited during the POSS Test.

How can I improve my mechanical reasoning skills for the POSS Test?

One of the best things you can do is practice. Taking practice mechanical reasoning questions, like those found on TestHQ, will help to brush up on any weaker areas of knowledge and familiarize you with the format of the POSS test questions.

Is the POSS Test the same for all plant operator positions?

No. The test can vary depending on the test provider and role you are applying for. Some roles require different levels and combinations of skills, so tests are adapted to select the best possible candidates. This may be why it’s difficult to find information about POSS Test pass rates.

Final Thoughts

Working within the power sector can be a challenging, yet rewarding, career. Passing the POSS Test is a key step in the journey to achieving the career of your dreams.

Thorough preparation for the POSS Test will mean that you feel calm and confident when taking an assessment that can be a deciding factor in your application process. 

Making the time to work through practice tests and sample POSS test questions will mean that you are familiar with the format and style of questioning in the test, and more confident in your abilities. 

Focusing on brushing up your knowledge in weaker areas will enable you to perform well overall and can lead to receiving the POSS test scoring level you need to move to the next stage of the recruitment process.