CSLB General Building (B) — All Questions

You opened the disconnect for a 480V motor circuit and applied your personal lock and tag. What is the FINAL step required before you may treat the conductors as safe to touch?

• a.Wait 30 minutes for any capacitors to bleed off
• b.Confirm the tag is signed and dated
• c.Test the conductors with an adequately rated voltage tester, then re-test the tester on a known live source to prove it works✓
• d.Notify the building owner in writing

Verifying the absence of voltage with a rated tester, and proving the tester is functioning before and after (live-dead-live), is the required final step. Waiting and checking the tag are part of lockout/tagout but do not confirm zero energy. Notifying the owner is not a safety verification of the conductors.Cal/OSHA Title 8 §3314

Which sequence correctly describes the basic lockout/tagout procedure before servicing electrical equipment?

• a.Notify affected employees, shut down, isolate/disconnect the energy source, apply locks and tags, release stored energy, then verify zero energy✓
• b.Apply locks first, then shut down, verify, and notify workers
• c.Verify zero energy, apply tags, shut down, then isolate
• d.Shut down, energize a test circuit, remove guards, then lock

The correct order is to notify, shut down, isolate, lock and tag, release stored energy, and finally verify zero energy. You cannot lock before shutting down, and verification must come at the end—not before isolation. Removing guards on a live test circuit is unsafe.Cal/OSHA Title 8 §3314

A crew of four electricians is servicing the same de-energized 480V feeder. How should lockout be handled?

• a.Only the foreman needs to apply a lock
• b.One shared lock is hung on a hook by the panel
• c.The first person in applies the lock and the last person out removes it for everyone
• d.Each authorized worker applies their own individual lock so the energy cannot be restored while anyone is exposed✓

In group lockout, every exposed worker applies their own lock (often on a lockbox or hasp) so power stays off until the last person removes their lock. A single foreman lock or shared lock leaves others exposed if someone else re-energizes. Relying on the first-in/last-out person defeats individual protection.Cal/OSHA Title 8 §3314

An electrician left the jobsite for the day and forgot to remove his lockout lock. How may it be removed?

• a.Any journeyman on site may simply cut it off
• b.Only under the employer's documented procedure after verifying the worker is off site and making a reasonable effort to notify them✓
• c.The foreman removes it immediately with no documentation
• d.Leave it in place and abandon the circuit permanently

A lock is normally removed only by the person who applied it. When that is not possible, the employer must follow a documented removal procedure, verify the worker has left, and make a reasonable effort to inform them before restoring energy. Cutting a lock off without that procedure risks energizing a circuit while someone is still working.Cal/OSHA Title 8 §3314

On a construction site, which receptacles must have GFCI protection for personnel?

• a.Only receptacles rated above 250 volts
• b.Only receptacles inside finished rooms
• c.None, as long as the power tools are double-insulated
• d.All 125-volt, 15-, 20-, and 30-ampere receptacles that are not part of the permanent building wiring✓

Temporary construction power requires GFCI protection on all 125V, 15/20/30A receptacles that are not part of the permanent wiring (or an assured equipment grounding conductor program). Voltage rating and room finish do not exempt them, and double-insulated tools do not remove the receptacle requirement.2023 NEC §590.6

A Class A GFCI intended to protect people trips at approximately what ground-fault current?

• a.About 20 milliamperes
• b.About 100 milliamperes
• c.About 5 milliamperes (in the 4-6 mA range)✓
• d.About 1 ampere

A Class A GFCI for personnel protection trips when ground-fault current reaches roughly 4 to 6 mA, low enough to protect against dangerous shock. 20 mA, 100 mA, and 1 A are all far above the let-go and ventricular-fibrillation thresholds and would allow a lethal shock.

What is the difference between a Class A (personnel) GFCI and a 30-milliampere 'equipment' ground-fault protection device?

• a.A Class A GFCI (about 5 mA) protects people from shock, while a 30 mA device protects equipment/wiring against fire and is not intended for personnel protection✓
• b.They are identical in function
• c.The 30 mA device protects people better than the 5 mA device
• d.Only the 30 mA device is allowed on construction sites

Class A GFCIs trip near 5 mA to protect people from electric shock, while equipment ground-fault protection (up to 30 mA) is designed to protect wiring and equipment and limit fire risk, not to protect a person. A 30 mA trip point is too high to reliably prevent a dangerous shock.

The arc flash boundary is best defined as the distance at which:

• a.The electrician can no longer physically reach the equipment
• b.The incident energy equals 1.2 cal/cm², the onset of a second-degree burn to bare skin✓
• c.The voltage on the conductors drops to zero
• d.The restricted approach boundary begins

The arc flash boundary is the distance from a potential arc source where incident energy is 1.2 cal/cm²—the level that would cause a second-degree burn to unprotected skin. It is a thermal (burn) boundary, not a reach limit or a shock (approach) boundary, and it has nothing to do with voltage reaching zero.NFPA 70E

In NFPA 70E, the 'limited approach boundary' is best described as:

• a.The distance within which a full arc-flash suit is always mandatory
• b.A distance from an exposed energized part within which a shock hazard exists; an unqualified person must not cross it without a qualified escort and appropriate PPE✓
• c.Exactly the same distance as the arc flash boundary
• d.A boundary that applies only to DC systems

The limited approach boundary is a shock-protection boundary; crossing it means a shock hazard is present, so unqualified persons need a qualified escort and PPE. It is distinct from the arc flash (thermal) boundary and applies to both AC and DC. The full arc suit is tied to incident energy, not this line.NFPA 70E

Crossing the restricted approach boundary toward an exposed energized part requires:

• a.No special precautions because it is close to the equipment
• b.Only safety glasses
• c.A hard hat and nothing else
• d.A qualified person, a documented plan/energized work permit, and appropriate shock PPE such as voltage-rated gloves✓

The restricted approach boundary is close to the live part, where an increased risk of shock from inadvertent movement exists. Only a qualified person may cross it, and only with a plan/permit and shock PPE (e.g., rated gloves). Glasses or a hard hat alone are inadequate for the shock hazard at that distance.NFPA 70E

An arc-flash study shows an available incident energy of 8 cal/cm² at the working distance. The arc-rated clothing and PPE must have an arc rating of:

• a.Less than the incident energy so it breathes better
• b.Exactly 1.2 cal/cm²
• c.At least equal to or greater than the available incident energy (8 cal/cm² or more)✓
• d.Any untreated cotton clothing is acceptable

Arc-rated PPE must have an arc rating equal to or greater than the available incident energy—here at least 8 cal/cm². Choosing PPE below the incident energy, or ordinary cotton (which can ignite), would not protect the worker. The 1.2 cal/cm² figure is the arc flash boundary threshold, not a PPE rating for this task.NFPA 70E

Rubber insulating gloves used for energized work on a 480V system must be:

• a.Rated for the voltage, worn with leather protectors, and inspected/air-tested before use✓
• b.Any leather work glove that fits
• c.Cotton gloves worn under nitrile gloves
• d.Only required for work above 1,000 volts

Voltage-rated rubber gloves must match or exceed the system voltage, be worn with leather protector gloves to prevent mechanical damage, and be inspected (and often air-tested) before each use. Leather or cotton alone provide no shock protection, and shock protection is required well below 1,000 volts.

Under Cal/OSHA and NFPA 70E, the primary/preferred way to protect workers from electrical hazards is to:

• a.De-energize the equipment and establish an electrically safe work condition whenever it is feasible✓
• b.Put on an arc-flash suit and work the equipment while energized
• c.Use insulated tools only and skip other protections
• d.Post a warning sign near the panel

The hierarchy of controls makes de-energizing and creating an electrically safe work condition the primary protection; energized work is only permitted when de-energizing is infeasible or introduces greater hazards. PPE, insulated tools, and signs are supplemental and do not replace de-energizing when it can be done.Cal/OSHA Title 8 §2320.2

An energized electrical work permit is generally required when:

• a.Any electrical work is performed, even de-energized
• b.Energized work is justified because de-energizing would introduce additional hazards or is infeasible, and the work is within the restricted approach or arc flash boundary✓
• c.The job simply takes longer than eight hours
• d.Working on a 24-volt control circuit

An energized work permit is required when justified energized work occurs within the restricted approach or arc flash boundary. Routine de-energized work does not need one, job duration is irrelevant, and very low-voltage circuits below the shock/arc thresholds generally do not require the permit.NFPA 70E

Before you rely on a voltage detector to verify absence of voltage, you should:

• a.Assume it works if the battery indicator light is on
• b.Only test after your hand is already on the conductors
• c.Do nothing, because meters never fail
• d.Test it on a known energized source before and after the check to confirm it is functioning (live-dead-live test)✓

A voltage tester must be proven functional on a known live source immediately before and after checking the circuit, so a failed meter cannot fool you into treating a live circuit as dead. A battery light does not prove the tester reads voltage, and touching first defeats the purpose of verification.

You are servicing a circuit that feeds a variable frequency drive (VFD) with large DC-bus capacitors. After disconnecting power you must:

• a.Immediately touch the terminals to test them
• b.Ignore stored energy because it is a low-voltage system
• c.Allow/assist the stored energy to dissipate and verify the capacitors are discharged before contact✓
• d.Short the source to ground while it is still energized

Capacitors in VFDs can hold a dangerous charge after power is removed, so you must let them discharge (per manufacturer's time/procedure) and verify they are discharged before touching. Touching immediately or ignoring stored energy risks a shock, and shorting an energized source is dangerous and can cause an arc flash.

You are installing a 480Y/277V panelboard with exposed live parts likely to require examination while energized. There is a concrete (grounded) wall on the opposite side of the working space (Condition 1). What is the minimum working-space depth in front of the panel?

• a.2 feet
• b.2½ feet
• c.3 feet✓
• d.4 feet

For nominal voltages of 151-600V, Condition 1 requires a minimum clear working-space depth of 3 feet in front of the equipment. The 3½- and 4-foot figures apply to Conditions 2 and 3 in that voltage range, and 2 or 2½ feet is never permitted for this equipment.2023 NEC §110.26

A 480V panel is installed so the worker stands between two energized sections with exposed live parts on both sides of the working space (Condition 3). What minimum working-space depth is required?

• a.4 feet✓
• b.3 feet
• c.3½ feet
• d.6 feet

For 151-600V equipment, Condition 3 (exposed live parts on both sides of the worker) requires a minimum 4-foot clear depth. 3 feet is Condition 1 and 3½ feet is Condition 2 at this voltage; 6 feet is not required for 480V.2023 NEC §110.26

The clear working space in front of a panelboard must be at least how wide and how high?

• a.18 inches wide and 6 feet high
• b.30 inches wide (or the width of the equipment, whichever is greater) and 6½ feet high✓
• c.24 inches wide and 5 feet high
• d.36 inches wide and 7 feet high

Working space must be at least 30 inches wide, or the width of the equipment if greater, and at least 6½ feet high (or the height of the equipment). 18, 24, or 36 inches and the other heights do not match the code minimums for width and headroom.2023 NEC §110.26

The 'dedicated equipment space' above an indoor panelboard or switchboard:

• a.Extends only 6 inches above the equipment
• b.Extends only 1 foot above the equipment
• c.Extends only 3 feet above the equipment
• d.Extends from the top of the equipment to 6 feet above it (or to a structural ceiling), and must be kept clear of foreign piping and ducts✓

The dedicated space extends from the top of the equipment upward 6 feet or to a structural ceiling, whichever is lower, and no foreign systems (piping, ducts) may occupy it. The 6-inch, 1-foot, and 3-foot answers understate the code-required dedicated space above electrical equipment.2023 NEC §110.26

For electrical equipment rated 1,200 amperes or more and over 6 feet wide, how many entrances to the working space are generally required?

• a.One 24-inch door is enough
• b.No entrance requirement applies
• c.A window at one end
• d.Two entrances/means of egress, one at each end of the working space (with limited exceptions)✓

Large equipment (1,200A or more and over 6 feet wide) generally requires an entrance/egress at each end of the working space so a worker can escape an arc flash. One door or no requirement leaves a worker potentially trapped behind an arcing fault. A window is not an approved means of egress here.2023 NEC §110.26

Live parts operating at 50 volts or more must be guarded against accidental contact by:

• a.A warning sign posted nearby
• b.Painting the parts a bright red color
• c.Approved enclosures, or location in a room/vault accessible only to qualified persons, or suitable elevation✓
• d.Wrapping them in electrical tape

Guarding of live parts is achieved through approved enclosures, access limited to qualified persons, or elevation out of reach. A sign, paint, or tape does not physically prevent accidental contact and is not an acceptable guarding method for exposed energized parts at 50V or more.2023 NEC §110.27

An electrical room containing exposed live parts that is accessible only to qualified persons must have:

• a.Entrances marked with conspicuous warning signs forbidding unqualified persons from entering✓
• b.No signage of any kind
• c.Carpeting on the floor
• d.Only a fire sprinkler and nothing else

Rooms or enclosures with exposed live parts restricted to qualified persons must have entrances marked with conspicuous warning signs that prohibit unqualified persons from entering. Omitting signage, adding carpet, or providing only a sprinkler does not satisfy the requirement to warn and restrict access.2023 NEC §110.27

The primary safety purpose of equipment grounding (bonding metal enclosures to the equipment grounding conductor) is to:

• a.Improve voltage regulation on the circuit
• b.Provide a low-impedance fault-current path so overcurrent devices open quickly and metal parts do not stay energized✓
• c.Reduce the customer's electric bill
• d.Eliminate the need for GFCI protection

Equipment grounding provides a low-impedance path for fault current so the breaker or fuse clears the fault fast and enclosures do not remain energized to a dangerous voltage. It does not regulate voltage, lower the bill, or replace GFCI protection, which detects small leakage currents to protect people.2023 NEC §250.4

Which statement about the grounded (neutral) and equipment grounding conductors is correct?

• a.They may be bonded together again at every subpanel
• b.They are bonded together only at the service (or separately derived source) and kept separate downstream in subpanels✓
• c.The equipment grounding conductor normally carries load current
• d.Neutrals and grounds are effectively the same conductor everywhere

The neutral and equipment grounding conductor are bonded only at the service or source; downstream subpanels keep them isolated so normal load current does not flow on grounding conductors and enclosures. Re-bonding at subpanels or treating them as one conductor creates parallel neutral paths and shock hazards.2023 NEC §250.24

A single ground rod electrode that does not achieve a resistance to earth of 25 ohms or less must be:

• a.Removed and left ungrounded
• b.Left as-is with no further action
• c.Replaced with a length of copper water pipe
• d.Supplemented by one additional electrode (such as a second rod) spaced at least 6 feet away✓

If a single made electrode does not meet 25 ohms or less, the Code requires adding one supplemental electrode located at least 6 feet from the first. Leaving it inadequate or removing it defeats the grounding, and a random copper pipe is not the prescribed supplemental electrode method.2023 NEC §250.53

The purpose of the main bonding jumper at a service is to:

• a.Connect two separate service panels together
• b.Bond the neutral bar only to the ground rod
• c.Connect the equipment grounding conductor/metal enclosure to the grounded (neutral) conductor at the service✓
• d.Carry the lighting load for the building

The main bonding jumper ties the equipment grounding system and service enclosure to the grounded (neutral) conductor at the service, completing the fault path back to the source. It is not a tie between two panels, not merely a neutral-to-rod link, and it never carries normal load current.2023 NEC §250.24

An excavation or trench that is how deep generally requires a protective system (sloping, shoring, or shielding) unless it is entirely in stable rock?

• a.5 feet or deeper✓
• b.10 feet or deeper
• c.2 feet or deeper
• d.20 feet or deeper

Trenches 5 feet deep or more must have a protective system (sloping/benching, shoring, or a trench shield) unless made entirely in stable rock. The 2-foot answer is too shallow, and waiting until 10 or 20 feet would leave workers unprotected in the depth range where fatal cave-ins commonly occur.Cal/OSHA Title 8 §1541.1

Who must inspect an excavation for hazards (before each shift and as conditions change) and classify the soil?

• a.A competent person who can identify hazards and is authorized to take prompt corrective action✓
• b.Any laborer available that day
• c.The city electrical inspector
• d.The electric utility company

Excavations must be inspected by a competent person—someone able to recognize hazards and authorized to take immediate corrective action, including ordering workers out. An untrained laborer, the electrical inspector, or the utility does not meet the competent-person requirement for trench safety.Cal/OSHA Title 8 §1541

Excavated soil (spoil) and equipment must be kept at least how far back from the edge of a trench?

• a.6 inches from the edge
• b.2 feet from the edge✓
• c.10 feet from the edge
• d.There is no setback requirement

Spoil piles and equipment must be kept at least 2 feet from the trench edge (or be restrained) so the surcharge load does not trigger a cave-in and material does not roll back onto workers. 6 inches is too close, 10 feet is more than required, and 'no requirement' is incorrect.Cal/OSHA Title 8 §1541

In a trench 4 feet or more deep, a stairway, ladder, or ramp must be provided so that:

• a.Workers can jump out if needed
• b.Only one is provided per trench regardless of its length
• c.It is optional as long as the trench is short
• d.No worker has to travel more than 25 feet of lateral distance to reach a means of exit✓

Trenches 4 feet or deeper require a ladder, stairway, or ramp located so that lateral travel to a means of exit is no more than 25 feet. Expecting workers to jump out, allowing only one regardless of length, or making it optional does not meet the egress requirement for deep trenches.Cal/OSHA Title 8 §1541

Before excavating a trench 5 feet or more deep into which a person must descend, a California employer generally must obtain:

• a.Nothing beyond a shovel
• b.A city business license
• c.A Cal/OSHA excavation/trench permit (project or annual) for trenches 5 feet or deeper that a worker will enter✓
• d.A building fire permit

Cal/OSHA requires a permit for construction of trenches 5 feet or more deep into which a person must descend. A business license or fire permit does not authorize the excavation, and 'nothing' ignores the permit requirement that helps ensure protective systems are planned.Cal/OSHA Title 8 §341

Before digging near underground utilities in California, you are required to:

• a.Just dig carefully by hand and hope for the best
• b.Call the fire department for a spotter
• c.Contact the regional one-call center (DigAlert/811) at least two working days in advance to have utilities marked✓
• d.Do nothing if the work is on private property

California law requires notifying the regional notification/one-call center (DigAlert, 811) at least two working days before excavating so member utilities can mark their lines. Digging blindly, calling the fire department, or assuming private property is exempt all risk striking energized or gas lines.

In California construction work, fall protection is generally required when a worker is exposed to a fall of what height or more?

• a.7½ feet✓
• b.4 feet
• c.10 feet
• d.20 feet

Cal/OSHA construction standards generally require fall protection when a worker is exposed to a fall of 7½ feet or more (stricter than the federal 6-foot general rule in some situations). The 10- and 20-foot answers would leave workers exposed, and 4 feet is the general-industry-style threshold, not the construction trigger here.

A standard guardrail system's top rail must be approximately what height above the walking/working surface?

• a.About 30 inches
• b.About 42 inches (plus or minus a few inches)✓
• c.About 54 inches
• d.About 24 inches

The top rail of a standard guardrail is about 42 inches above the surface, high enough to stop a worker from going over. 30 or 24 inches is too low to be effective, and 54 inches is higher than the standard specifies for the top rail.Cal/OSHA Title 8 §3209

A straight or extension ladder should be set at a safe angle by placing its base at what distance from the wall?

• a.4 feet out for every 4 feet of height
• b.2 feet out for every 4 feet of height
• c.3 feet out for every 4 feet of height
• d.1 foot out from the wall for every 4 feet of ladder working length (the 4-to-1 rule)✓

The 4-to-1 rule places the ladder base 1 foot away from the wall for each 4 feet of working length, giving a stable climbing angle of about 75 degrees. Setting it 2, 3, or 4 feet out for every 4 feet of height makes the ladder too flat and likely to slide out at the base.Cal/OSHA Title 8 §3276

A straight or extension ladder used to reach an upper landing must extend at least how far above the landing surface?

• a.6 inches above the landing
• b.1 foot above the landing
• c.2 feet above the landing
• d.3 feet above the landing✓

A ladder used for access to a landing must extend at least 3 feet above the landing (or be provided with grab rails) so the worker has a secure handhold when stepping on and off. 6 inches, 1 foot, or 2 feet does not give a safe handhold at the transition point.Cal/OSHA Title 8 §3276

When an electrician may be working near energized electrical parts or overhead lines, which ladder should be used?

• a.An aluminum ladder because it is lighter and stronger
• b.Any metal ladder that is available
• c.A non-conductive ladder such as fiberglass or dry wood, never a metal ladder near live electrical work✓
• d.A steel ladder that is bonded to a ground rod

Electricians must use non-conductive ladders (fiberglass or dry wood) near energized parts and overhead lines so the ladder cannot become an electrical path. Aluminum, other metal, or a 'grounded' steel ladder can conduct fault current through the worker and is prohibited for this work.

The safe practice when climbing a portable ladder is to:

• a.Maintain three points of contact and face the ladder while climbing✓
• b.Carry tools in both hands so you can work faster at the top
• c.Climb up the back side of the ladder
• d.Stand on the very top cap for extra reach

Maintaining three points of contact (two hands and one foot, or two feet and one hand) while facing the ladder keeps you stable if you slip. Carrying tools in both hands, climbing the back, or standing on the top cap all remove stability and are common causes of ladder falls.

A space is a 'permit-required confined space' when it is large enough to enter, has limited means of entry/exit, is not designed for continuous occupancy, AND:

• a.It is always located outdoors
• b.It contains or has the potential to contain a hazardous atmosphere, engulfment, entrapment, or other serious hazard✓
• c.It is smaller than 4 feet in any direction
• d.It has good natural ventilation

A permit-required confined space adds at least one serious hazard—hazardous atmosphere, engulfment, an inwardly converging/entrapping configuration, or another recognized hazard—to the basic confined-space criteria. Being outdoors, small, or well-ventilated does not define a permit space; the presence of a serious hazard does.Cal/OSHA Title 8 §5157

Before entering a permit-required confined space, the atmosphere should be tested in what order?

• a.Toxic gases first, then oxygen, then flammables
• b.Oxygen first, then flammable gases/vapors, then toxic air contaminants✓
• c.Flammables first, then oxygen, then toxics
• d.No testing is needed if a fan is running

Atmospheric testing is done in the order oxygen, flammability, then toxicity, because most flammable and toxic sensors depend on a known oxygen level to read correctly. Reversing the order can give false readings, and running a fan does not substitute for testing before entry.Cal/OSHA Title 8 §5157

A normal, safe breathable oxygen concentration in a confined space is approximately:

• a.19.5% to 23.5%✓
• b.10% to 15%
• c.25% to 30%
• d.About 5%

The acceptable oxygen range for entry is about 19.5% (minimum) to 23.5% (maximum); below 19.5% is oxygen-deficient and above 23.5% is oxygen-enriched and a fire hazard. 10-15% and 5% are dangerously deficient, and 25-30% is enriched and increases combustion risk.Cal/OSHA Title 8 §5157

A permit-required confined space entry requires an attendant who:

• a.May enter to help if the entrant collapses inside
• b.Can leave the post to take a lunch break
• c.Is optional as long as the entrants carry radios
• d.Remains outside, monitors the entrants, and never enters to attempt rescue but summons trained rescue services instead✓

The attendant stays outside, continuously monitors entrants, and calls trained rescuers rather than entering—many confined-space fatalities are would-be rescuers who rushed in. The attendant cannot leave the post or enter, and radios do not eliminate the required attendant for a permit space.Cal/OSHA Title 8 §5157

On many California jobsites, which OSHA safety training is typically expected for supervisors versus entry-level workers?

• a.OSHA 10 for supervisors and OSHA 30 for the workers
• b.Both groups take an OSHA 4-hour course
• c.OSHA 30 for supervisors/those with safety responsibility and OSHA 10 for entry-level workers✓
• d.No safety training course exists for construction

The OSHA 30-hour course is aimed at supervisors and workers with safety responsibility, while the OSHA 10-hour course targets entry-level workers. Reversing the two, an imaginary 4-hour course, or claiming no course exists all misstate the standard training structure.

The OSHA 10-hour Construction course primarily covers:

• a.How to pass the C-10 licensing exam
• b.Advanced electrical load calculations
• c.Recognition, avoidance, and prevention of common jobsite hazards, including the 'Focus Four' (falls, electrocution, struck-by, caught-in/between)✓
• d.How to calculate union dues

OSHA 10 teaches workers to recognize, avoid, and prevent common construction hazards, emphasizing the Focus Four. It is a safety awareness course, not licensing exam prep, load-calculation training, or a class on union administration.

Electrocution is one of OSHA's construction 'Focus Four' hazards. The other three are:

• a.Noise, dust, heat, and cold exposure
• b.Falls, struck-by, and caught-in/between✓
• c.Chemical, biological, and radiological hazards
• d.Slips on wet floors only

The Focus Four—responsible for most construction deaths—are falls, electrocution, struck-by, and caught-in/between. Noise/dust, chem/bio/radiological, and simple slips are real concerns but are not OSHA's Focus Four for construction fatalities.

An unqualified worker must walk past an open 480V panel with exposed live parts to reach a work area. What must happen?

• a.They must stay outside the limited approach boundary unless continuously escorted by a qualified person and using appropriate PPE✓
• b.Crossing the arc flash boundary is perfectly fine for them
• c.They may cross the restricted approach boundary since it is only 480V
• d.There are no restrictions at all for 480V equipment

Unqualified persons must stay outside the limited approach boundary unless escorted by a qualified person and protected with appropriate PPE. They are never allowed to cross the restricted approach boundary, and 480V exposed parts absolutely carry shock and arc-flash hazards that require these restrictions.NFPA 70E

An arc-flash hazard warning label applied to equipment should list information such as:

• a.The paint color of the enclosure
• b.Only the equipment manufacturer's name
• c.The phone number of the electric utility
• d.Nominal system voltage, the arc flash boundary, and the available incident energy or the required level of PPE✓

A useful arc-flash label conveys the nominal voltage, arc flash boundary, and either available incident energy or the required PPE so workers can select proper protection. Paint color, the manufacturer alone, or the utility's phone number do not tell a worker how to protect against the arc-flash hazard.2023 NEC §110.16

Which equipment, when likely to require examination or servicing while energized, must be field- or factory-marked to warn of potential arc-flash hazards?

• a.Residential 15-ampere receptacles
• b.Only equipment operating above 1,000 volts
• c.Household doorbell transformers
• d.Switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers in other than dwelling units✓

The Code requires arc-flash hazard marking on switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers in other than dwellings likely to be worked on energized. Small residential receptacles and doorbell transformers are not the targeted equipment, and the requirement is not limited to over 1,000V.2023 NEC §110.16

When working within the restricted approach boundary of exposed energized parts, hand tools should be:

• a.Insulated/voltage-rated tools designed for the voltage being worked on✓
• b.Any chrome-plated tools that look clean
• c.Ordinary tools wrapped in a layer of electrical tape
• d.Not a concern because gloves alone are enough

Energized work within the restricted approach boundary requires insulated, voltage-rated hand tools to prevent a fault or shock if a tool contacts a live part. Chrome tools, tools wrapped in tape, or relying on gloves alone do not provide the tested insulation that rated tools offer.

To protect other workers from an area where justified energized work is being performed, the qualified person should:

• a.Do nothing because only they are at risk
• b.Use barricades, warning signs, and an attendant if needed to keep unqualified persons out of the boundaries✓
• c.Turn off the room lights to signal danger
• d.Simply work faster to reduce exposure time

Energized work areas must be protected with barricades, signs, and an attendant when needed so unqualified persons stay outside the approach boundaries. Doing nothing exposes others, turning off lights creates a new hazard, and working fast does not control access to the hazard zone.

Class 00 and Class 0 rubber insulating gloves are rated for maximum AC use voltages of approximately:

• a.5,000 volts and 10,000 volts
• b.250 volts and 500 volts
• c.500 volts and 1,000 volts respectively✓
• d.50 volts and 100 volts

Class 00 gloves are rated to about 500V and Class 0 gloves to about 1,000V AC maximum use voltage. The 5,000/10,000V figures apply to higher classes, and 250/500V or 50/100V understate the ratings of these two glove classes.

When an arc-flash risk assessment requires it, in addition to arc-rated clothing a worker must protect the face and head with:

• a.An arc-rated face shield with balaclava, or an arc-rated flash-suit hood✓
• b.A pair of tinted sunglasses
• c.A simple disposable dust mask
• d.Nothing extra beyond the shirt

Face and head protection for arc flash means an arc-rated face shield with a balaclava (sock hood) or a full arc-rated flash-suit hood, selected to the incident energy. Sunglasses, a dust mask, or no additional protection do not shield the face from the intense heat and light of an arc.NFPA 70E

Standard electrical arc-flash PPE also includes head and hearing protection because:

• a.Electrical arcs are silent and harmless to the ears
• b.Hard hats are always optional for electricians
• c.An arc blast produces intense heat, pressure, and sound, so a non-conductive (Class E) hard hat and hearing protection are required✓
• d.Only the gloves matter during an arc event

An arc blast releases extreme heat, a pressure wave, and very loud sound, so a Class E (electrical) hard hat and hearing protection are part of the PPE. Arcs are far from silent, hard hats are not optional in this work, and gloves alone do not address the head, hearing, and blast hazards.

For electrical work, a hard hat should be:

• a.Class C (conductive/vented) for better airflow
• b.Class E, tested to protect against electrical contact up to 20,000 volts✓
• c.Any bump cap will do
• d.Class G only, tested to 1,000 volts

Class E (electrical) hard hats are dielectrically tested to protect against contact up to about 20,000 volts, making them the correct choice for electrical work. Class C is conductive and unsafe near electricity, a bump cap offers little impact protection, and Class G (about 2,200V) provides far less electrical protection than Class E.

Immediately after you open a disconnect switch, all the conductors on the load side should be treated as:

• a.Safe to handle right away
• b.Safe as soon as the indicator light goes off
• c.Safe after waiting about five seconds
• d.Energized and dangerous until you have tested and verified the absence of voltage✓

Conductors must be treated as energized until a rated tester confirms the absence of voltage; a disconnect could be mislabeled, back-fed, or have stored energy. Assuming safety from an open switch, an indicator light, or a short wait has caused many electrocutions.Cal/OSHA Title 8 §2320.1

On de-energized conductors or equipment where accidental re-energization or induced voltage is possible, workers protect themselves by applying:

• a.Nothing extra, since the switch is open
• b.Temporary protective grounds (a grounding cluster) to keep the conductors at or near zero potential✓
• c.Only rubber insulating blankets over the parts
• d.A warning sign at the panel and nothing more

Temporary protective grounds bond de-energized conductors together and to ground, so any accidental re-energization or induced voltage is shunted safely instead of flowing through a worker. An open switch, blankets, or a sign alone do not protect against an unexpected re-energization the way applied grounds do.

In a dwelling, 125-volt 15- and 20-ampere receptacles must be GFCI-protected in which of the following groups of locations?

• a.Bedrooms only
• b.The living room
• c.The attic
• d.Bathrooms, kitchens, garages, outdoors, crawl spaces, unfinished basements, laundry areas, and within 6 feet of a sink✓

The Code requires GFCI protection for dwelling receptacles in wet or damp and higher-risk areas—bathrooms, kitchens, garages, outdoors, crawl spaces, unfinished basements, laundry areas, and near sinks. Bedrooms, the living room, or the attic are not the code-listed GFCI locations by themselves.2023 NEC §210.8

What is the fundamental difference between AFCI and GFCI protection?

• a.GFCI protects people from shock by detecting ground-fault (leakage) current, while AFCI protects against fires by detecting dangerous arcing faults✓
• b.They are identical devices with different names
• c.AFCI detects the 5 mA shock current to protect people
• d.GFCI is designed to prevent arcing fires in walls

A GFCI detects small ground-fault/leakage current to protect people from shock, whereas an AFCI senses the signature of dangerous arcing and opens to prevent fires. They are not the same device, AFCI is not a 5 mA shock protector, and GFCI is not primarily a fire-prevention arc detector.

Flexible cords and extension cords used on a construction site must be:

• a.Repaired with electrical tape over any cuts
• b.Run through doorways where they can be pinched shut
• c.Of the hard-service or extra-hard-service type, include an equipment grounding conductor, and be inspected and free of damage✓
• d.Ordinary 16 AWG lamp cord for lighter tools

Jobsite cords must be hard- or extra-hard-service rated, contain a grounding conductor, and be inspected and undamaged. Taping over cuts, pinching cords in doorways, or using light lamp cord all create shock, ground-fault, and fire hazards and are not acceptable.

As an alternative to GFCI protection on certain construction-site receptacles, an employer may instead implement:

• a.An assured equipment grounding conductor program with documented, scheduled inspections and continuity tests of cords and equipment✓
• b.No protection at all, relying on worker care
• c.Doubling the fuse or breaker size on the circuit
• d.A lockout/tagout program in place of any grounding checks

OSHA allows an assured equipment grounding conductor program—documented, scheduled continuity and terminal tests on cords and equipment—as an alternative to GFCI on some receptacles. Providing no protection, oversizing overcurrent devices, or substituting a lockout program does not satisfy the ground-fault protection requirement.

Which set of actions best establishes an 'electrically safe work condition' before hands-on work begins?

• a.Putting on rubber gloves and working the circuit while it is still energized
• b.Posting a warning sign near the equipment
• c.De-energize the source, lock and tag out, test for the absence of voltage, and apply temporary grounds where required✓
• d.Reducing the connected load to lower the current

An electrically safe work condition is established by de-energizing, locking/tagging out, verifying zero voltage with a rated tester, and applying grounds where required. Gloved live work, a sign, or reducing load do not remove the energy source and therefore do not create a safe work condition.Cal/OSHA Title 8 §3314