Question 1

GFCI protection must be provided for all temporary wiring used during construction. What does GFCI stand for?

Accepted Answer

GFCI stands for Ground Fault Circuit Interrupter. GFCIs monitor the current flowing through the circuit and trip when they detect an imbalance (ground fault) as small as 5 milliamps.

Question 2

What are the two options for ground-fault protection on construction sites using temporary wiring?

Accepted Answer

OSHA requires either GFCI protection or an assured equipment grounding conductor program (AEGCP) for all 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites that are not part of permanent wiring.

Question 3

What is the minimum safe working distance from overhead power lines rated up to 50kV for cranes, equipment, and materials?

Accepted Answer

Any vehicle, equipment, or materials must maintain at least 10 feet of clearance from overhead power lines rated 50kV or less.

Question 4

Lockout/tagout procedures are used to:

Accepted Answer

Lockout/tagout procedures ensure that circuits and equipment are de-energized before employees perform any work on or near them, preventing unexpected energization.

Question 5

Extension cords used on construction sites must be of which type?

Accepted Answer

Extension cords used on construction sites must be three-wire type (including a ground conductor) and must be hard or extra-hard usage rated.

Question 6

What is the primary purpose of grounding electrical equipment?

Accepted Answer

Grounding provides a low-impedance path for fault current to return to the source, causing the circuit breaker or fuse to trip and removing the hazardous voltage.

Question 7

What current level can cause ventricular fibrillation and death?

Accepted Answer

Current in the range of 50-100 milliamps (0.05-0.1 amps) can cause ventricular fibrillation and death. Even relatively small amounts of current can be lethal.

Question 8

Temporary wiring on construction sites must be removed:

Accepted Answer

Temporary electrical power and lighting installations shall be removed immediately upon completion of construction or the purpose for which the wiring was installed.

Question 9

What is the minimum approach distance for unqualified persons to exposed energized parts operating at 50kV or less?

Accepted Answer

Unqualified persons must maintain a minimum distance of 10 feet from overhead lines operating at 50kV or less.

Question 10

Damaged or defective electrical equipment must be:

Accepted Answer

Worn or frayed electric cords or cables shall not be used. Damaged or defective electrical equipment must be immediately removed from service until properly repaired.

Question 11

What does a GFCI detect?

Accepted Answer

A GFCI detects a difference (imbalance) between the current flowing through the hot (ungrounded) conductor and the neutral (grounded) conductor. A difference of 5 milliamps triggers the GFCI to trip.

Question 12

Each disconnecting means for motors and appliances must be legibly marked to indicate its:

Accepted Answer

Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident.

Question 13

Electrical panels must have a clear working space of at least how many inches wide and how many inches deep in front of the panel?

Accepted Answer

Working space in the direction of access to live parts operating at 600V or less must be at least 30 inches wide and 36 inches deep.

Question 14

What is the purpose of double-insulated tools?

Accepted Answer

Double-insulated tools have two layers of insulation to protect the user from electrical shock. They do not require a third-wire ground and are marked with a square-within-a-square symbol.

Question 15

Before performing lockout/tagout, the employer must ensure:

Accepted Answer

Lockout/tagout requires notification of affected employees, de-energization of circuits, application of locks and tags, and verification that the circuit is indeed de-energized using testing equipment.

Question 16

The ground prong on a three-prong plug must NEVER be:

Accepted Answer

The grounding prong on a plug must never be removed, bent, or otherwise made non-functional. The grounding conductor is a critical safety feature.

Question 17

Which of the following is NOT a factor that determines the severity of an electrical shock?

Accepted Answer

The severity of electrical shock depends on the amount of current, the path it takes through the body, and the duration of contact. The color of the wire is for identification only.

Question 18

Temporary lights used on construction sites must be:

Accepted Answer

Temporary lights shall be equipped with guards to prevent accidental contact with the bulb, unless the bulb is deeply recessed in a reflector.

Question 19

An assured equipment grounding conductor program (AEGCP) must include testing of equipment at least:

Accepted Answer

Under an AEGCP, each cord set, attachment cap, plug, and receptacle of cord sets, and any equipment connected by cord and plug must be tested before first use, after repair, and at intervals not exceeding 3 months.

Question 20

Which of the following is an electrical hazard that can cause burns, electrocution, or explosions?

Accepted Answer

Arc flash is a dangerous release of energy caused by an electrical fault that can produce extreme heat (up to 35,000 degrees F), intense light, pressure waves, and shrapnel.

Question 21

Flexible cords used on construction sites must be rated as:

Accepted Answer

Flexible cords and cables used on construction sites must be designated as hard usage or extra-hard usage, such as types S, ST, SO, STO, SJ, SJO, or equivalent.

Question 22

Electrical equipment used in wet or damp locations must be:

Accepted Answer

Electrical equipment used in wet or damp locations must be identified for and suitable for such use. Equipment in wet locations must be weatherproof.

Question 23

The path of least resistance for electrical current through the human body is typically:

Accepted Answer

The most dangerous path is hand to hand across the chest, as the current passes through the heart. Hand to foot is also dangerous. The path through the body determines the severity of the shock.

Question 24

What is the purpose of a lockout device?

Accepted Answer

A lockout device uses a lock to hold an energy-isolating device (such as a switch or breaker) in the safe (off) position, physically preventing anyone from re-energizing the circuit.

Question 25

Employees must not enter spaces containing exposed energized parts unless:

Accepted Answer

Employees may not enter spaces containing exposed energized parts unless illumination is provided that enables them to perform the work safely.

Question 26

Receptacles on construction sites that are not part of the permanent wiring must have:

Accepted Answer

All 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites that are not part of the permanent wiring must have GFCI protection or be covered by an AEGCP.

Question 27

What must be done before re-energizing circuits after lockout/tagout?

Accepted Answer

Before circuits are re-energized, all employees must be clear of the circuits and equipment, locks and tags must be removed by the person who placed them, and all affected employees must be notified.

Question 28

Electrical cords that pass through doorways or other pinch points must be protected from:

Accepted Answer

Extension cords and flexible cords must be protected from damage, particularly where they pass through doorways, windows, or other openings where they could be pinched or cut.

Question 29

What type of electrical injury is caused by an electrical arc producing extreme temperatures?

Accepted Answer

Electrical burns are caused by electrical arcs that produce extreme temperatures. Arc flash burns can cause severe injury even without direct contact with the electrical source.

Question 30

Live parts of electric equipment operating at 50 volts or more must be:

Accepted Answer

Live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact by approved cabinets or other forms of approved enclosures.

Question 31

What is the OSHA standard number for electrical safety in construction?

Accepted Answer

Subpart K of 29 CFR 1926 covers electrical safety requirements for construction, including sections 1926.400 through 1926.449.

Question 32

When working near overhead power lines with voltages greater than 50kV, the minimum clearance distance must be increased by what amount for each additional 10kV?

Accepted Answer

For voltages over 50kV, the clearance distance of 10 feet must be increased 4 inches for every 10kV over 50kV.

Question 33

Overcurrent protection (circuit breakers or fuses) is designed to protect:

Accepted Answer

Overcurrent protection devices such as fuses and circuit breakers are designed to protect conductors and equipment by opening the circuit when current exceeds safe levels.

Question 34

When using portable generators on construction sites, what grounding requirement applies?

Accepted Answer

Under certain conditions, the frame of a portable generator may serve as the grounding electrode. Otherwise, the generator must be connected to a grounding electrode system.

Question 35

What is the most common cause of electrical fatalities on construction sites?

Accepted Answer

Contact with overhead power lines is the most common cause of electrical fatalities in the construction industry. Workers must maintain safe distances and use proper precautions.

Question 36

A tagout device is:

Accepted Answer

A tagout device is a prominent warning device, such as a tag, that is securely attached to the energy-isolating device to warn employees that the equipment must not be re-energized.

Question 37

Which of the following is a proper practice when working around electricity?

Accepted Answer

All circuits and equipment should be treated as energized until tested and verified otherwise. This basic safety practice prevents accidental electrocution.

Question 38

What is the minimum headroom clearance for electrical service rooms?

Accepted Answer

The minimum headroom of working spaces about service equipment, switchboards, panelboards, or motor control centers shall be 6 feet 3 inches.

Question 39

Electrical cords must NOT be:

Accepted Answer

Unless specifically designed for such use, flexible cords and cables may not be stapled, hung from nails, or suspended by wire. These practices can damage the insulation.

Question 40

A 'qualified person' in electrical work is defined as:

Accepted Answer

A qualified person is one who has received training in and has demonstrated skills and knowledge in the construction and operation of the electric equipment and installations, and the hazards involved.

Question 41

Conductive materials and equipment that may contact energized parts must be handled to prevent:

Accepted Answer

Conductive materials and equipment that are in contact with any part of an employee's body shall be handled in a manner that will prevent them from contacting exposed energized conductors or circuit parts.

Question 42

When a GFCI trips, what should the employee do?

Accepted Answer

When a GFCI trips, it indicates a ground fault or equipment malfunction. The employee should stop work, investigate the cause, and correct the problem before resetting and continuing work.

Question 43

Wet conditions increase the risk of electrical shock because:

Accepted Answer

Water is a conductor of electricity. Wet conditions lower the body's natural electrical resistance, making it easier for dangerous levels of current to flow through the body.

Question 44

Portable electrical equipment must be handled in a manner that will not cause damage. When disconnecting a cord, the employee should:

Accepted Answer

When disconnecting electrical equipment, always grasp the plug, not the cord. Pulling on the cord can damage the internal wiring and insulation, creating a shock hazard.

Question 45

Only a __________ person may work on or near exposed energized electrical parts.

Accepted Answer

Only qualified persons may work on electric circuit parts or equipment that have not been de-energized. A qualified person is trained to work safely on energized circuits and to recognize and avoid electrical hazards.

Question 46

What is the primary purpose of a lockout/tagout (LOTO) procedure?

Accepted Answer

Lockout/tagout (LOTO) procedures are designed to prevent the unexpected energization, startup, or release of stored energy during servicing and maintenance of machines and equipment. This protects workers from hazardous energy sources.

Question 47

Ground-fault circuit interrupters (GFCIs) are designed to trip when they detect a ground-fault current of approximately how many milliamps?

Accepted Answer

GFCIs are designed to detect a difference of approximately 5 milliamps between the current flowing in the hot and neutral conductors and to trip (de-energize) the circuit within 1/40 of a second. This threshold is below the level that can cause serious injury to most people.

Question 48

On construction sites, GFCI protection is required for all 120-volt, single-phase, 15- and 20-ampere receptacle outlets that are not part of the permanent wiring. What is the alternative to GFCI protection?

Accepted Answer

OSHA allows employers to use either GFCIs or an assured equipment grounding conductor program (AEGCP) to protect employees from ground-fault hazards on construction sites. The AEGCP includes regular testing and inspection of equipment grounding conductors.

Question 49

What is the minimum safe clearance distance for work performed near overhead power lines energized at up to 50 kV?

Accepted Answer

OSHA requires a minimum clearance distance of 10 feet from overhead power lines energized at up to 50,000 volts (50 kV). For voltages over 50 kV, the clearance must be increased by 4 inches for every additional 10 kV.

Question 50

Which of the following best describes a 'qualified person' under OSHA's electrical standards?

Accepted Answer

Under OSHA's construction electrical standards, a qualified person is one who has been trained in and has demonstrated skills and knowledge in the construction and operation of electric equipment, and the hazards involved. This includes the ability to distinguish exposed energized parts and to determine nominal voltages and clearance distances.

Question 51

Temporary wiring on construction sites must be removed immediately upon completion of the project or when?

Accepted Answer

Temporary electrical power and lighting wiring methods may be used during construction and must be removed immediately upon completion of construction or the purpose for which the wiring was installed.

Question 52

What type of electrical injury is caused by the passage of current through the body?

Accepted Answer

Electrical shock occurs when current passes through the body. The severity depends on the amount of current, the path of the current through the body, and the duration of exposure. Even small amounts of current can cause ventricular fibrillation and death.

Question 53

Extension cords used on construction sites must be of what type?

Accepted Answer

Flexible cords used on construction sites must be designated for hard or extra-hard usage (such as types S, ST, SO, STO) and must be three-wire type with an equipment grounding conductor. This ensures durability and grounding protection in the harsh construction environment.

Question 54

What is the primary hazard when using electrical equipment in wet or damp conditions?

Accepted Answer

Water is an excellent conductor of electricity. When working in wet or damp conditions, the body's resistance to electrical current is significantly reduced, greatly increasing the risk and severity of electrical shock. GFCI protection is essential in these environments.

Question 55

Electrical equipment and circuits must be de-energized before work begins unless de-energizing introduces additional or increased hazards. Who may work on energized circuits?

Accepted Answer

Only qualified persons may work on electric circuit parts or equipment that have not been de-energized. They must use appropriate safety-related work practices, including the use of proper PPE and insulated tools, and must be trained to recognize and avoid electrical hazards.

Question 56

Under an assured equipment grounding conductor program (AEGCP), how often must all cord sets and receptacles be tested?

Accepted Answer

Under an AEGCP, each cord set, attachment cap, plug, and receptacle must be tested before first use, before being returned to service after any repairs, and at intervals not to exceed 3 months. Tests must verify that the equipment grounding conductor is electrically continuous.

Question 57

When performing lockout/tagout, after de-energizing circuits and equipment, what must be done before starting work?

Accepted Answer

After circuits are de-energized and locked/tagged out, the worker must verify that the equipment is indeed de-energized by attempting to operate the normal operating controls, and by using test instruments to confirm zero energy state. This verification step is critical for worker safety.

Question 58

What is an arc flash?

Accepted Answer

An arc flash is a dangerous release of energy caused by an electric arc, which can produce temperatures exceeding 35,000 degrees Fahrenheit, intense light, pressure waves, and molten metal. Arc flash events can cause severe burns, blindness, hearing damage, and death.

Question 59

What must be done with the path to ground for electrical equipment on construction sites?

Accepted Answer

The path to ground from circuits, equipment, and enclosures must be permanent and continuous. A proper grounding path ensures that fault current can flow back to the source and trip overcurrent protective devices, preventing shock hazards.

Question 60

Overhead power lines near construction sites must have warning signs posted when equipment will be operated nearby. What additional precaution is required when cranes operate near power lines up to 50 kV?

Accepted Answer

When operating cranes or similar equipment near overhead power lines energized at up to 50 kV, a minimum clearance distance of 10 feet must be maintained between any part of the crane or its load and the energized power line. Additional clearance is required for higher voltages.

Question 61

Which of the following is required when temporary lights are used in construction?

Accepted Answer

Temporary lights must be equipped with guards to prevent accidental contact with the bulb, unless the lamp is recessed or the reflector is constructed to make bulb contact unlikely. Exposed bulbs pose a burn and fire hazard and can shatter, causing injury.

Question 62

What PPE is most appropriate for an electrician performing work on energized circuits where an arc flash hazard exists?

Accepted Answer

When arc flash hazards exist, workers must wear arc-rated (AR) clothing and PPE appropriate for the hazard level, including arc-rated face shields, insulating gloves rated for the voltage, and other PPE determined by the arc flash risk assessment. Standard clothing can ignite and cause severe burns during an arc flash event.

Question 63

Unqualified persons must maintain a minimum approach distance of at least ____ from overhead power lines rated at 50 kV or below.

Accepted Answer

Unqualified persons and any conductive objects they may contact must stay at least 10 feet away from overhead power lines rated at 50 kV or less. This distance applies to all activities, including material handling, scaffolding erection, and use of equipment.

Question 64

Live parts of electrical equipment operating at 50 volts or more must be guarded against accidental contact by which of the following methods?

Accepted Answer

Live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact by approved cabinets or other forms of approved enclosures, or by location in a room, vault, or similar enclosure accessible only to qualified persons, or by elevation of 8 feet or more above the floor.

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