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100+ Free RSES CMS HVACR Electrical Practice Questions

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2026 Statistics

Key Facts: RSES CMS HVACR Electrical Exam

100

Practice Questions

OpenExamPrep

100

Exam Questions

RSES

80%

Passing Score

RSES

$35

Exam Fee

RSES

14

Electrical Categories

RSES

CM Required

Prerequisite

RSES

The RSES CMS HVACR Electrical Specialist exam is one of eight Certificate Member Specialist (CMS) exams offered by the Refrigeration Service Engineers Society (RSES). It is a 100-question multiple-choice written exam requiring an 80% score to pass, and candidates must already be an RSES Certificate Member (CM) in good standing. The exam fee is $35, and it is proctored at chapter test days, regional and international seminars, or the annual RSES conference. Content spans 14 categories: fundamental electricity, DC and AC principles, series and parallel circuits, electrical symbols and schematics, electrical safety, resistors, capacitors, transformers/power supplies, relays/contactors/starters, motors and compressors, conductors, and solid-state and miscellaneous components. This free prep includes 100 research-based practice questions with explanations and an AI tutor.

Sample RSES CMS HVACR Electrical Practice Questions

Try these sample questions to test your RSES CMS HVACR Electrical exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In a basic atom, which subatomic particle carries a negative charge and is responsible for current flow in a conductor?
A.Proton
B.Neutron
C.Electron
D.Nucleus
Explanation: Electrons carry a negative charge and orbit the nucleus. Free electrons in the outer (valence) shell of a conductor drift when a voltage is applied, and this organized flow of electrons is electric current.
2What is the unit of electrical resistance?
A.Volt
B.Ampere
C.Ohm
D.Watt
Explanation: Resistance is measured in ohms, symbolized by the Greek letter omega. One ohm allows one ampere to flow when one volt is applied across it.
3Ohm's law states that the current in a circuit is directly proportional to voltage and inversely proportional to what quantity?
A.Power
B.Resistance
C.Capacitance
D.Frequency
Explanation: Ohm's law is I = E / R. Current rises as applied voltage rises and falls as resistance rises, so current is inversely proportional to resistance.
4A heater draws 10 amperes when connected to a 120-volt supply. What is its resistance?
A.0.083 ohms
B.12 ohms
C.120 ohms
D.1,200 ohms
Explanation: Using Ohm's law R = E / I, R = 120 V / 10 A = 12 ohms. Rearranging Ohm's law to solve for resistance is a core HVACR troubleshooting skill.
5Using Watt's law, how much power does a 240-volt circuit dissipate when it draws 5 amperes?
A.48 watts
B.245 watts
C.1,200 watts
D.12,000 watts
Explanation: Watt's law states P = E x I, so P = 240 V x 5 A = 1,200 watts. Power equals voltage multiplied by current in a resistive load.
6What is the defining characteristic of direct current (DC)?
A.It periodically reverses direction
B.It flows in only one direction
C.It has a frequency of 60 Hz
D.It cannot be stored in a battery
Explanation: Direct current flows in only one direction at a steady polarity. Batteries, rectified power supplies, and most control circuits with electronic boards rely on DC.
7What is the standard frequency of alternating current power supplied to HVACR equipment in the United States?
A.50 Hz
B.60 Hz
C.120 Hz
D.400 Hz
Explanation: Line power in the United States is 60 Hz, meaning the AC waveform completes 60 full cycles each second. Motor speed and transformer design depend on this frequency.
8For a sine wave AC voltage, how is the RMS (effective) value related to the peak value?
A.RMS = peak x 1.414
B.RMS = peak x 0.707
C.RMS = peak x 0.637
D.RMS = peak x 2
Explanation: The RMS value of a sine wave equals 0.707 times the peak value. RMS is the effective value that produces the same heating as an equivalent DC voltage, so 120 V RMS has about a 170 V peak.
9Three resistors of 10 ohms, 20 ohms, and 30 ohms are wired in series. What is the total circuit resistance?
A.5.45 ohms
B.20 ohms
C.60 ohms
D.600 ohms
Explanation: In a series circuit, total resistance is the sum of the individual resistances: 10 + 20 + 30 = 60 ohms. Series resistance always increases as more resistors are added.
10Two 20-ohm resistors are connected in parallel. What is the total resistance of the combination?
A.5 ohms
B.10 ohms
C.20 ohms
D.40 ohms
Explanation: For two equal resistors in parallel, total resistance equals one resistor divided by the number of resistors: 20 / 2 = 10 ohms. Parallel resistance is always less than the smallest branch resistor.

About the RSES CMS HVACR Electrical Exam

The RSES CMS HVACR Electrical Specialist exam is a 100-question, multiple-choice written exam for HVACR technicians who hold the RSES Certificate Member (CM) credential. It requires a score of 80% or better and covers electrical theory, Ohm's and Watt's law, AC/DC and series/parallel circuits, single- and three-phase power, motors and motor controls, capacitors, relays, contactors, solid-state components, and electrical troubleshooting and safety.

Assessment

100 multiple-choice questions covering 14 electrical categories, 80% required to pass; this practice bank is 100 selected-response items

Time Limit

Proctored written exam at an RSES test event (no fixed published time limit)

Passing Score

80%

Exam Fee

$35 per exam (Refrigeration Service Engineers Society (RSES))

RSES CMS HVACR Electrical Exam Content Outline

18%

Electrical Theory & Ohm's/Watt's Law

Fundamental electricity, voltage/current/resistance, conductors and insulators, and Ohm's law and Watt's law calculations

12%

AC/DC Circuits

Direct vs alternating current, the 60 Hz sine wave, RMS/peak values, frequency, power factor, and reactance

15%

Series & Parallel Circuits

Series, parallel, and combination circuit analysis of total resistance, voltage drops, branch currents, and power

13%

Single & Three-Phase Power

120/240 V single-phase and three-phase systems, motor rotation, voltage unbalance, and single-phasing faults

22%

Motors & Motor Controls

PSC, shaded-pole, ECM, and three-phase motors; compressor terminals; LRA/FLA, slip, speed, and motor protection

12%

Capacitors, Relays & Contactors

Run/start/dual-run capacitors, transformers, contactors, relays, and solid-state components such as diodes and triacs

8%

Electrical Troubleshooting, Meters & Safety

Voltmeters, ohmmeters, clamp ammeters, meggers, schematics, voltage-drop diagnostics, grounding, and circuit protection

How to Pass the RSES CMS HVACR Electrical Exam

What You Need to Know

  • Passing score: 80%
  • Assessment: 100 multiple-choice questions covering 14 electrical categories, 80% required to pass; this practice bank is 100 selected-response items
  • Time limit: Proctored written exam at an RSES test event (no fixed published time limit)
  • Exam fee: $35 per exam

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

RSES CMS HVACR Electrical Study Tips from Top Performers

1Weight your study toward motors/motor controls and circuit analysis — together they are the largest share of the exam
2Memorize and practice Ohm's law (I = E/R) and Watt's law (P = E x I), and be ready to rearrange them quickly
3Know the single-phase compressor terminals: C-R is lowest resistance, C-S is higher, and R-S is the highest reading
4Understand the difference between run and start capacitors, and how potential and current relays drop the start winding out
5Practice reading ladder diagrams and tracing a cooling sequence of operation from the thermostat through the safeties to the contactor
6Complete all 100 practice questions and review every miss with the AI tutor before sitting the exam

Frequently Asked Questions

How many questions are on the RSES CMS HVACR Electrical exam and what score do I need?

The RSES HVACR Electrical Specialist exam has 100 multiple-choice questions and requires a score of 80% or better to pass. It is one of eight RSES Certificate Member Specialist (CMS) exams.

How much does the RSES HVACR Electrical CMS exam cost?

The fee is $35 per CMS exam. You must also be an RSES Certificate Member (CM) in good standing, which is a separate membership and certification.

Do I need to be an RSES member to take the HVACR Electrical CMS exam?

Yes. Any RSES Certificate Member (CM) in good standing may sit a CMS specialty exam. The CMS designation builds on the core CM credential and recognizes specialized expertise.

What topics does the HVACR Electrical Specialist exam cover?

It covers 14 categories including fundamental electricity, DC and AC principles, series and parallel circuits, schematics, electrical safety, resistors, capacitors, transformers, relays/contactors/starters, motors and compressors, conductors, and solid-state components.

Where can I take the RSES HVACR Electrical CMS exam?

RSES proctors CMS exams at state and regional training events, local chapter test days, International Seminars, and the annual RSES conference. Check the RSES events calendar or your local chapter for testing dates.

Is this free RSES HVACR Electrical practice as good as paid prep?

Our 100 practice questions cover the same electrical categories as the official RSES exam outline, with a teaching explanation for every answer plus free daily AI tutor interactions. All content is free forever and updated for 2026.