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BASIC NEC 2023

Electrical Measuring Instruments Practice Test

Free online electrical measuring instruments practice test. 25 basic electrical questions on multimeters, clamp meters, meggers, and safe test procedures. Good for electrician exam prep.

TOPICS COVERED

Multimeter Basics Voltmeter Connection Ammeter Connection Ohmmeter Safety Clamp Meter Basics Ammeter Danger

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Knowing which meter to use, how to connect it, and how to use it safely is a core electrician skill. Remember the basic connection rules: a voltmeter connects in PARALLEL (across) what it measures; an ammeter connects in SERIES (in-line) with the circuit. An ohmmeter must only be used on a de-energized circuit. A clamp meter measures current without breaking the circuit at all. Always confirm your meter is set to the right function and range before testing, and follow the "live-dead-live" method: test a known live source, test your circuit, then test the known live source again.

13

Questions

38 min

Time

75%

Pass

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Electrical Measuring Instruments Practice Test — Question List

Question 1: A multimeter is a test instrument that can typically measure:

Voltage, current, and resistance, among other functions
Only AC voltage and nothing else
Only the temperature of a conductor
Only the length of a cable run

Question 2: To measure voltage across a component, a voltmeter must be connected:

In parallel with the component
In series with the component
It must break the circuit open
It does not matter how it is connected

Question 3: To measure the current flowing through a circuit, an in-line ammeter must be connected:

In series with the circuit
In parallel with the circuit
Across the supply terminals only
It does not matter how it is connected

Question 4: Before using an ohmmeter to measure resistance in a circuit, you must first:

De-energize (turn off and disconnect power from) the circuit
Increase the circuit voltage
Connect the meter in series with the load while powered
Set the meter to the amps function

Question 5: A clamp meter measures current without breaking the circuit because it:

Senses the magnetic field created by current flowing through the conductor
Physically cuts the conductor to insert a shunt
Measures the temperature of the conductor
Requires the circuit to be de-energized first

Question 6: Why is it dangerous to connect an in-line ammeter directly across (in parallel with) a voltage source?

An ammeter has very low internal resistance, creating a near short circuit
An ammeter has very high internal resistance and will read zero
It will simply display "OL" with no other effect
It is not actually dangerous to do this

Question 7: Using an ohmmeter on a circuit that is still energized (has power applied) can:

Damage the meter and give a false or inaccurate reading
Always give a perfectly accurate resistance reading
Have no effect on the meter at all
Automatically switch the meter to voltage mode

Question 8: A "continuity test" on a multimeter tells you whether:

There is a complete, unbroken electrical path between two points
The voltage between two points is exactly 120 V
The frequency of the supply is correct
The circuit is currently carrying full load current

Question 9: A megohmmeter (megger) is primarily used to test:

The insulation resistance of a conductor or winding
The exact voltage of a 480 V panel
The speed of a rotating motor
The frequency of the AC supply

Question 10: A wattmeter is designed to directly measure:

Real power (watts) in a circuit
Only the resistance of a load
Only the frequency of the supply
Only the insulation quality of a cable

Question 11: A meter's CAT (category) rating, such as CAT III or CAT IV, indicates:

The level of transient overvoltage protection the meter provides for the location it is rated to be used in
The brand of the meter only
How many functions the meter can perform
The battery life of the meter

Question 12: The internal fuse in a multimeter's current-measuring input is there to protect the meter if it is:

Accidentally connected across a voltage source while set to measure current
Left switched off for a long period of time
Dropped from a short height
Used to measure a completely dead circuit

Question 13: A non-contact voltage tester (proximity tester) is a useful first check for voltage, but electricians should NOT rely on it alone because it:

Can give false readings and does not confirm the circuit is safe to touch
Is always 100% accurate under every condition
Can measure exact resistance values
Requires the circuit to be de-energized to work at all

EXAM CARD BASIC

Questions13

Time limit38 min

Pass score75%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

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Source: NEC 2026 (NFPA 70)