Journeyman Electrician Practice Test 29

Question 1: A 13.8 kV switchgear has exposed live parts on one side of the working space and grounded parts on the other side (Condition 2). What is the minimum working space depth?

• 9 ft
• 8 ft
• 6 ft
• 5 ft

NEC Reference: NEC 110.34(A) and Table 110.34(A)

Question 2: A ground ring electrode must be buried at a depth of not less than:

• 18 in.
• 24 in.
• 30 in.
• 36 in.

NEC Reference: NEC 250.53(F)

Question 3: Type AC Cables shall not be permitted to use in the following locations?

• damp and wet locations
• concealed locations
• exposed locations
• dry locations

NEC Reference: NEC 320.12

Question 4: A box listed for use in wet locations needs a drainage opening drilled in the field. What size opening is permitted?

• No opening may ever be added in the field
• Any size, if it is later taped over
• Up to ½ in. in diameter
• ⅛ in. to ¼ in. in diameter

NEC Reference: NEC 314.15

Question 5: What is the unit of apparent power?

• Volt-ampere (VA)
• Joule (J)
• Volt-ampere reactive (VAR)
• Watt (W)

Question 6: The turns ratio of the transformer is 10:4 which of the following is the primary voltage of the transformer if the rated secondary is 120 volts.

• 300 volts
• 48 volts
• 1200 volts
• 480 volts

Question 7: If the supply frequency is doubled, what happens to the capacitive reactance of a circuit?

• It doubles
• It increases four times
• It stays the same
• It is reduced to half

Question 8: What is the maximum current a 400-watt, 1-ohm resistor can carry without exceeding its power rating?

• 40 A
• 20 A
• 4 A
• 2 A

Question 9: Stopping a motor immediately on overload would create a greater hazard (for example, a process that must shut down in an orderly way). What does 430.44 permit?

• Wiring the overload to a supervised alarm
• Removing all overload protection from the motor
• Relying on the branch-circuit breaker alone
• Doubling the overload relay setting

NEC Reference: NEC 430.44

Question 10: A panelboard uses a series-combination rating with 10,000 A branch breakers. Motors connected between the main fuse and those branch breakers have a combined full-load current of 120 A. May the series rating be used?

• No; 120 A exceeds 1% of 10,000 A
• Only if all the motors are 3-phase
• Yes; motors never affect series ratings
• Yes, if each motor is under 10 hp

NEC Reference: NEC 240.86(C)

Question 11: Rod, pipe and plate electrodes must be free from:

• Copper plating or cladding
• Hot-dip galvanizing
• Contact with the soil
• Paint, enamel or other insulating coatings

NEC Reference: NEC 250.53(A)(1)

Question 12: What is the capacitive reactance (XC) of a capacitor in a direct current (DC) circuit?

• Zero ohms — capacitors pass DC freely
• Infinite ohms — capacitors block DC completely
• Equal to the resistance in the circuit
• Equal to the supply voltage divided by DC current

Question 13: A transformer with a turns ratio of 1:4 (step-up) has a primary current of 20 amperes. What is the secondary current?

• 80 amperes
• 5 amperes
• 20 amperes
• 4 amperes

Question 14: At resonance in a series RLC circuit, which of the following is true?

• XL is greater than XC
• XL equals XC and circuit impedance equals resistance only
• XC is greater than XL
• Current is at minimum

Question 15: A 120-volt branch circuit has 2 Ω of total conductor resistance and carries 10 A. What voltage reaches the load?

• 80 V
• 100 V
• 118 V
• 120 V

Question 16: A 3-phase motor has overload protection provided by thermal protectors built into the motor windings. Is a separate overload relay in each phase still required?

• Yes — always required regardless of other protection
• No — thermal protectors in the motor may substitute for separate overload devices
• Yes — thermal protectors are not recognized by the NEC
• No — three-phase motors never need overload protection

NEC Reference: NEC 430.37

Question 17: Rock prevents a ground rod from being driven straight down. At what maximum angle from vertical may it be driven?

• 90°
• 60°
• 45°
• 30°

NEC Reference: NEC 250.53(A)(4)

Question 18: How must Type AC cable be secured?

• Within 12 in. of boxes and every 4½ ft
• At intervals not exceeding 8 ft
• Only at the two ends, with no interior support
• It never needs to be supported

NEC Reference: NEC 320.30(B)

Question 19: In a purely resistive AC circuit, what is the phase angle between voltage and current?

• 90 degrees
• 0 degrees — current and voltage are in phase
• 45 degrees
• 30 degrees

Question 20: Unguarded live parts of 4,160-volt equipment are located above a working space. What is their minimum elevation?

• 6 ft 6 in.
• 8 ft 6 in.
• 9 ft
• 10 ft

NEC Reference: NEC 110.34(E) and Table 110.34(E)

Question 21: Power factor is expressed as:

• A voltage from −1 V to +1 V
• Always exactly 1.0 in any AC circuit
• A resistance from 0 to 100 ohms
• A ratio from 0 to 1.0, lagging or leading

Question 22: A building has several separate concrete-encased electrodes (foundation footings with rebar). How many must be bonded into the grounding electrode system?

• Only one is required
• All of them
• At least two
• None; they are optional

NEC Reference: NEC 250.52(A)(3)

Question 23: A 5 kW electric motor runs for 8 hours. How much electrical energy does it consume?

• 5 kWh
• 40 kWh
• 8 kWh
• 400 kWh

Question 24: Transformer secondary conductors are NOT required to have overcurrent protection at the point where they connect to the transformer if they:

• Are installed in metal conduit
• Are insulated for 90 °C
• Are rated 600 V or less
• Meet a 240.21(C) secondary rule

NEC Reference: NEC 240.21(C)

Question 25: A motor disconnecting means is not required to be in sight from the motor if the controller disconnect .............

• Is within 100 feet of the motor
• Can be individually locked in the open position
• Is rated for at least 200A
• Has a red handle

NEC Reference: NEC 430.102(B)

Question 26: What is the synchronous speed of an 8-pole induction motor on a 60 Hz supply?

• 1,800 rpm
• 1,200 rpm
• 900 rpm
• 720 rpm

Question 27: A 4 ft length of trade size ¾ listed liquidtight flexible metal conduit (LFMC), with listed fittings, supplies equipment protected at 40 A. No flexibility is needed after installation. May the LFMC serve as the equipment grounding conductor?

• No; LFMC can never be an EGC
• Yes; it meets the size, length and 60 A limits
• Only if it is ⅜ in. or ½ in. trade size
• Only if it is shorter than 3 ft

NEC Reference: NEC 250.118

Question 28: A 480-volt panelboard (277 V to ground) faces exposed live parts across the working space (Condition 3). What is the minimum working space depth?

• 3 ft
• 3½ ft
• 4 ft
• 5 ft

NEC Reference: NEC 110.26(A)(1) and Table 110.26(A)(1)

Question 29: A voltmeter used to measure voltage across a load must be connected .............

• In series with the load
• In parallel across the load
• At the power source terminal only
• In series with the ammeter

Question 30: In a delta (Δ) connected 3-phase system, what is the relationship between line voltage and phase voltage?

• Line voltage equals √3 times phase voltage
• Line voltage equals phase voltage
• Line voltage is always less than phase voltage
• Line voltage equals 2 times phase voltage