ESCO Electrical Employment Ready Practice Test

These questions are part of the practice quiz. Start practicing

• In a series circuit, does the current remain the same through all components?
• As temperature increases, what happens to the resistance of a PTC thermistor?
• In outlets, what is the difference between a plug and a receptacle?
• Which of the following expresses Ohm's law to calculate current from voltage and resistance?
• Ideal transformer power conservation.
• What amperage measurement would you expect if you clamped your meter around both wires in a two-wire circuit?
• In a typical 120/240 V circuit, which color is commonly used for the second hot conductor?
• Name three factors that affect conductor ampacity.
• Which device is primarily used to interrupt current to protect wiring and components in fault conditions?
• The thermal overload contacts on a line starter are usually ______ reset:
• Current is defined as the flow of:
• Which device is commonly used on a single-phase fractional horsepower compressor to disconnect the start winding?
• What is the standard form of Ohm's Law?
• A 120 V supply delivers 2 A to a load; what is the power in watts?
• What is the purpose of a bonding jumper?
• In the schematic, the main power supply across L1–L2 is:
• A fault with the blower motor or blower relay would most likely produce which symptom?
• The coil on line #11 does not control which device?
• The voltage to ground of a high leg or stinger leg on a three-phase open delta system will be approximately?
• Which function is not typically provided by a digital multimeter?
• An electronically commutated motor (ECM) is designed to:
• To change rotation on a three-phase motor, which wiring change is required?
• In a parallel circuit, how does current divide and how is total resistance determined?
• Which of the following is NOT a safe practice when using a multimeter on energized circuits?
• Why are load calculations important in electrical design?
• Like charges do what to each other?
• What symptom would you expect if the blower motor runs while HP/LP safety devices are open and the compressor is not?
• The voltage across the condenser fan motor during operation is:
• Which statement about ampacity is true?
• Excessive current can be caused by:
• In a motor control circuit, a device used to open and close the motor circuit under load is commonly a:
• In a circuit with a 24V, 20-ohm contactor coil wired in series with a 24V, 200-ohm control relay across a 24V supply, which device energizes?
• Transformers are rated by:
• A thermocouple can:
• Which of the following is a conductor?
• In a series circuit, does the voltage across each component stay the same?
• What is the purpose of a grounding electrode system?
• What is generally considered the maximum allowable supply voltage variation?
• What term describes the output side of a transformer?
• The mains supply voltage in this setup is:
• What is the purpose of a ground fault circuit interrupter (GFCI)?
• The voltage across the transformer primary during operation is:
• When testing a motor with an ohmmeter, the measurements C-R = 4, C-S = 6.2, R-ground = 20.4 indicate what condition?
• Voltage can be calculated by:
• In a parallel circuit, the voltage across each branch equals the source voltage.
• What is an open circuit?
• The safety ground conductor is usually colored:
• Which tool would you use to verify electrical continuity?
• What is the total resistance of the two devices in series in the arrangement described above?
• In electrical wiring, a black colored wire indicates
• What is the purpose of lockout/tagout in preventing injuries?
• Three resistors in parallel: 10 ohm, 20 ohm, 20 ohm. What is the total resistance?
• Which colors are commonly used for hot conductors in a standard US residential circuit?
• The crankcase heater will operate under which condition?
• Which of the following is equal to 100 milliamps?
• A reading of 0 volts between Y and the coil input on line #11 under thermostat closed and fan auto indicates which condition?
• In a parallel circuit, how does the total resistance compare to the individual resistances?
• When testing a capacitor with an analog or digital ohmmeter, the meter should:
• Which of the following motors is most energy efficient?
• Which statement about the coil on line #11 is accurate given the schematic?
• Utilities companies usually provide residential homes with
• Where are GFCIs typically required in residential wiring?
• The unit of electric current is the ampere, abbreviated as:
• Three 300 ohm resistors are wired parallel. What is the total resistance?
• When given voltage and resistance, how do you calculate current?
• Which statement about current is true?
• A parallel circuit consists of R1 = 30 ohms, R2 = 15 ohms, R3 = 10 ohms. If the current through R2 = 4 amps, what is the source voltage?
• If the conductor in an AC circuit is wound into a coil, the resulting EMF opposes supply voltage. This is called:
• What is the purpose of a motor starter's overload protection?
• For a four-pole, 60 Hz motor, the synchronous speed is approximately:
• What is the current through each heater in the parallel circuit described above?
• What is the minimum number of wires required between two start/stop push button controls?
• Which of the following meters must use internal power to check a load or circuit?
• Which device is used to control a larger circuit with a smaller control signal?
• The safety ground conductor color is usually colored:
• As temperature increases, what happens to the resistance of an NTC thermistor?
• In a circuit with resistors in series, what happens to current when one resistor's value increases?
• Which of the following is the symbol for impedance?
• Which test is commonly used to verify insulation integrity by applying a high voltage between conductors and earth?
• Which protective device is designed to interrupt current during overcurrent or short-circuit conditions?
• What is a safe practice when using a multimeter on energized circuits?
• Which statement best describes the relationship of windings resistance in a healthy three-phase motor?
• To discharge a capacitor safely, which component value is recommended for the discharge resistor?
• What is the primary purpose of a circuit breaker in a panel?
• If the thermostat is closed and the blower motor is running, which condition would prevent the compressor from running according to the described safety interlocks?
• Three defrost heaters, each 15 ohms, are wired in parallel to a 120 volt power supply. How many watts are consumed?
• On an electronic oil safety switch, what changes the pressure signal to an electrical signal?
• Capacitors are rated in:
• Utilities provide residential power with what voltage and phase configuration?
• What is the approximate voltage drop across the 20-ohm coil in the series arrangement described above?
• Single-phase motor speed is determined by
• What is the purpose of a wiring diagram?
• On a good single-phase compressor, which winding terminals have the highest resistance?
• The solenoid valve operates on the principle of
• The _______ drawing illustrates where the components are located on the appliance:
• How is a resistor represented in a schematic diagram in the US?
• Which term describes opposition to alternating current in a circuit?
• When checking windings on a three-phase motor, the resistance readings should:
• If a voltage drop is excessive, what is the typical effect on electrical performance?
• The synchronous speed of a four-pole, 60 Hz motor is:
• How can capacitor usage affect power factor in AC circuits?
• What device allows current to be measured without breaking a circuit by clamping around a conductor?
• In a series circuit, to find total resistance you:
• Which formula represents Ohm's Law in its basic form?
• Why is Lockout/Tagout important in electrical work?
• Capacitor-start, capacitor-run motors provide
• How are fuses sized?
• The low-voltage output between the transformer secondary and thermostat side is:
• What is the typical voltage of a residential branch circuit in the US?
• In a parallel circuit, the current through a resistor can be found using I = V / R.
• What does NEC stand for and what is its purpose?
• Circuit breakers and fuses provide:
• Before working on a circuit, which safety steps should you take?
• What is a relay and where is it used?
• If HP, LP, overloads, and oil pressure switch are open, which device is still likely running?
• In the schematic, what voltage would be found from terminal Y to the input side of the coil on line #11 when the thermostat is closed and the fan is set to auto?
• Which statement best describes the primary function of a grounding conductor connected to earth?
• Why are insulation temperature ratings important for conductors?
• Capacitor-start, capacitor-run motors provide
• A three-phase load requires a minimun of:
• In a two-resistor parallel circuit, total resistance is described as:
• When resistors are wired in parallel, which statement is true about the voltage across each resistor?
• What is the purpose of a GFCI?
• What is impedance?
• What insulation types are common for conductors used in commercial and residential wiring and rated for 90°C?
• A transformer with primary 100 turns and secondary 200 turns, input 120V, what is the output?
• Which of the following describes the role of a grounding electrode system in electrical safety?
• What connects the T1, T2, and T3 terminals on a contactor?
• In a series circuit, the voltage drop across each load will
• On a contactor, the terminals T1, T2, and T3 are typically connected to
• Which device is used to switch a large circuit under the control of a small electrical signal?
• Why should an ohmmeter be kept away from a charged capacitor when testing?
• The coil on line #11 does not control which component?
• What color indicates a grounding conductor in electrical systems?
• Three resistors are wired in parallel. Two have a value of 12 ohms, one of 6 ohms. What is the total resistance?
• The voltage across the energized contacts in line #8 during operation is:
• What is the common residential single-family service voltage?
• Which colors are commonly used for hot conductors in a typical 120/240 V circuit?
• An electron has:
• The rotation of a single-phase motor is determined by
• What is the correct formula for determining wattage?
• In a parallel circuit, how does the total current relate to the branch currents?
• Which statement about capacitors and power factor is true?
• The voltage from terminal G to the load side of the transformer (thermostat closed, fan auto) is:
• Capacitor-start, capacitor-run motors provide what torque characteristics?
• An ohmmeter should never be connected to which of the following?
• Resistance can be calculated by:
• Electricity can produce:
• Which term describes the coil connected to the power source in a transformer?
• How do you calculate electrical power?
• The voltage across the transformer primary during operation is:
• What is the primary difference between AC and DC current?
• Amps can be calculated by: A. E / R, B. W / E, C. The square root of W / R, D. All of the above
• What is the function of a grounding electrode rod or conductor outside a building?
• In a three-phase system, what is meant by a phase?
• With the motor running at full load, voltmeter leads placed on L1 and T1 show 0 volts. What does this indicate?
• How much resistance must be placed in a 120 volt circuit to limit the current to 2 amps?
• What considerations are involved in PPE for a task involving heat and electricity?
• Which of the following materials would be best suited for use as a semiconductor?
• What color is typically used for a green equipment grounding conductor?
• Lockout/tagout is used to prevent which hazard?
• Across L1 to L2 in the schematic would be:
• Which device is most commonly used to convert pressure into an electrical signal in HVACR systems?
• What PPE is essential for protecting eyes and face during electrical work?
• The meter on a house measures the _______ passing through it.
• If a 30 ohm resistor in a parallel network carries 2 amperes, the voltage across that resistor is:
• How many watts are used by a heater operating on 460 volts and drawing 5 amps?
• Impedance is measured in
• What is resistance?
• The symbol for current is:
• Under the same scenario but with the compressor and condenser fan motor not running while the blower motor is running, which components are most likely open?
• If a 9 V supply delivers 0.5 A to a load, what is the power in watts?
• What is the standard voltage configuration for most US residential services?
• What is the first step in a proper lockout/tagout (LOTO) procedure?
• A parallel circuit contains an 18 ohm and a 9 ohm resistor. What is the total resistance?
• Regarding capacitor use in a single-phase motor circuit, the capacitor is connected how with the start winding?
• What is the function of an AFCI device?
• What voltage is most commonly used for lighting circuits in homes in the United States?
• Which unit measures electrical resistance?
• Which statement best describes the function of a line starter?
• How does a transformer alter voltage and current?
• In outlets, which term describes the female connector mounted on devices or walls?
• Which PPE is required for arc-flash risk according to NFPA 70E guidelines?
• The most common transducer used with HVACR equipment creates a signal based on what physical quantity?
• What does NEC stand for and what is its role?
• Direct digital control (DDC) is best described as
• Which drawing type specifically shows components' locations rather than wiring schematics?
• Ohm's Law states resistance can be calculated as the ratio of voltage to current. Which option matches this definition?
• Differentiate between a short circuit and a ground fault.
• Which color is commonly used for neutral conductors in the US?
• Which material is typically used as a semiconductor in electronics?
• What color is typically used for a neutral conductor in residential wiring in the US?
• Direct digital control (DDC) is
• Which is an acceptable temporary replacement capacitor for a 35 MFD, 440 VAC capacitor?
• Distinguish between bonding and grounding in a building electrical system.
• Which arrangement describes standard 120/240 V residential service in the US?
• Contactors are rated according to the maximum amperage through the:
• What causes voltage drop, and why is it important to consider?
• One horsepower is equal to ______ watts
• Any material that will readily release electrons is called:
• In a series circuit, what is true about current and total resistance?
• Ohm's Law relates which three electrical quantities?
• The voltage across L1 to L2 would be 240 V; which option lists the correct voltage across L1-L2?
• Which of the following is equal to 2.1 kW?
• If contacts become badly pitted, it is acceptable to:
• Capacitors are always connected _______ with the start winding?
• In AC circuits, the EMF in a coil opposing the applied voltage is known as
• Which interpretation is correct when no voltage is detected across L1 and T1 while the motor is loaded?
• A step-up transformer increases
• The voltage across the contacts energized in line #8 during operation (thermostat closed, fan auto) is:
• Which type of thermistor is typically used as a temperature sensor whose resistance decreases with rising temperature?
• How do you determine the ampacity of a conductor from NEC tables?
• A transformer has 1000 turns on the primary side and 500 on the secondary. What is the output if the input is 120v?
• The voltage from terminal G to the load side of the transformer (thermostat closed, fan auto) is:
• What basic function does a diode serve in a DC circuit?
• What is current?
• The voltage across the condenser fan motor during operation is:
• Which device is used to control motor operation by switching high current in the circuit?
• In a parallel circuit, adding another parallel path will cause the total resistance to:
• In a circuit with a 24V, 20-ohm contactor coil wired in series with a 24V, 200-ohm control relay across a 24V supply, which device energizes?
• A diode is used to:
• In a three-phase system, a minimum of how many supply lines are required?
• The crankcase heater’s operation is tied to compressor status; which statement best reflects this relationship?
• Which of the following would be considered an inductive load?
• When troubleshooting the A/C schematic, if the thermostat contacts are closed, the compressor and condenser fan motor are short cycling, and the blower motor is not running, what is the most likely fault?
• How do you calculate current using Ohm's Law?
• Why are torque specifications used on electrical connections?
• What instrument is used to measure voltage, current, and resistance?
• In an ideal transformer, stepping up the voltage results in what change to current?
• A transformer has 1000 turns on the primary side and 2000 on the secondary. What is the output if the input is 120v?
• To discharge a capacitor, which method is recommended?
• Which component is the male connector in a plug-receptacle pair?
• In motor control, what is the role of a contactor?
• Which statement describes the safety role of wearing appropriate PPE during electrical work?
• Three defrost heaters, each 15 ohms, are wired in parallel to a 120 volt power supply. What is the total current drawn by the heaters?
• A capacitor analyzer is designed to check:
• Which standard governs electrical safety in the workplace, including PPE requirements for arc-flash hazards?
• What is the main purpose of a circuit breaker?
• What is insulation resistance testing and why is it performed?
• A device with overload protection used to control a motor is a: