CSLB Trade — Electrical (C-10) — All Questions
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115 questions
How must the water in a permanently installed pool be bonded to the equipotential bonding system?
- a.The pool water does not need to be bonded
- b.Through a conductive surface of at least 9 square inches in contact with the pool water✓
- c.Through 1 square inch of conductive surface
- d.Through 36 square inches of conductive surface
Section 680.26(C) requires the pool water to be bonded using an adequate conductive surface exposed to the pool water having a total area of at least 9 square inches, such as a listed metal fitting. This ensures the water is at the same potential as the surrounding bonded parts.2023 NEC §680.26
Low-voltage lighting systems covered by Article 411 are generally limited to what maximum voltage?
- a.12 volts only
- b.120 volts
- c.30 volts (or 15 volts where in direct contact with water)✓
- d.60 volts
Section 411.7 limits low-voltage lighting systems to a maximum of 30 volts (42.4 volts peak), reduced to 15 volts (21.2 volts peak) where the luminaires are installed in wet contact such as in a fountain. The 12-volt figure is a common operating voltage but is not the code maximum.2023 NEC §411.3
How must overcurrent devices in an emergency system be coordinated?
- a.Coordination is not addressed by the NEC
- b.Coordination is prohibited
- c.Coordination is required only above 1000 volts
- d.Selectively coordinated with all supply-side overcurrent protective devices✓
Section 700.32 requires emergency-system overcurrent protective devices to be selectively coordinated with all supply-side overcurrent devices. Selective coordination ensures that only the device nearest a fault opens, so a fault on one branch does not shut down the entire emergency system.2023 NEC §700.32
How does a Class 3 circuit differ from a Class 2 circuit?
- a.Class 3 is always lower power than Class 2
- b.Class 3 is a line-voltage power circuit
- c.Class 2 and Class 3 are identical
- d.Class 3 circuits are permitted at higher voltage and power than Class 2 and require additional protection against shock✓
Class 3 power sources are allowed to supply higher voltage and power levels than Class 2, so Article 725 imposes additional requirements to protect against electric shock. Class 3 is still a limited-energy circuit, not a general line-voltage power circuit.2023 NEC §725.121
When communications conductors share an enclosure with electric light or power conductors, what is required?
- a.They shall be separated by a barrier or maintained spacing from the power conductors✓
- b.They may share the same compartment freely
- c.No separation is required at any voltage
- d.They must be spliced together
Section 800.133 requires communications conductors to be separated from electric light, power, and Class 1 conductors, generally by a barrier or by maintaining a minimum spacing, when they occupy the same enclosure. Mixing them freely or splicing them to power conductors is not permitted.2023 NEC §800.133
What distinguishes a non-power-limited fire alarm (NPLFA) circuit from a power-limited (PLFA) circuit?
- a.NPLFA circuits are not power-limited and must use Chapter 3 wiring methods, while PLFA circuits are power-limited✓
- b.NPLFA circuits are always 24 V battery-supplied
- c.Both are power-limited circuits
- d.PLFA circuits use Chapter 3 wiring methods only
An NPLFA circuit is supplied by a source exceeding the power-limited restrictions and therefore must be installed using Chapter 3 wiring methods with 600-volt-rated conductors. PLFA circuits use a power-limited source (100 VA maximum) and may use the lighter power-limited cabling of Article 760 Part III.2023 NEC §760.41
Where must the initiation device for PV rapid shutdown be located?
- a.Inside the inverter only
- b.Only on the roof next to the array
- c.Readily accessible and located outside the building, or at an approved location for first responders✓
- d.It is not required
Section 690.12(C) requires the rapid-shutdown initiation device to be readily accessible and located outside the building or at another location approved for first responders. Placing it inside the inverter or hidden at the array would defeat its purpose of quick emergency access.2023 NEC §690.12
How must exposed non-current-carrying metal parts of PV module frames and equipment be treated?
- a.Exposed non-current-carrying metal parts of PV module frames and equipment shall be bonded and grounded✓
- b.Bond only the inverter
- c.Frames need no bonding
- d.Use only bare copper laid loosely on the roof
Section 690.43 requires exposed non-current-carrying metal parts of module frames, racking, and equipment to be bonded together and connected to an equipment grounding conductor, using listed devices or means. Bonding only the inverter or leaving frames unbonded would leave metal surfaces energized during a fault.2023 NEC §690.43
What marking must a generator carry?
- a.Only the serial number
- b.Only the fuel type
- c.A nameplate giving the maker, rated frequency, power factor, kW or kVA, voltage, and rating such as continuous or standby✓
- d.No marking is required
Section 445.11 requires each generator to have a nameplate giving the manufacturer, rated frequency, number of phases, subtransient and transient impedances, power factor, rating in kW or kVA, normal volts and amperes, and the rating (such as continuous, standby, or prime). A serial number or fuel-type marking alone would not satisfy this requirement.2023 NEC §445.11
An on-site generator serving as the emergency source must have an on-site fuel supply sufficient for what minimum operating time at full load?
- a.Fuel for 30 minutes
- b.Fuel for 1 hour
- c.No on-site fuel is needed
- d.On-site fuel for not less than 2 hours of full-demand operation✓
Section 700.12 requires a generator set used as an emergency source to have an on-site fuel supply sufficient for not less than 2 hours of full-demand operation of the system. A shorter supply, or relying only on an outside fuel source, would not meet the emergency requirement.2023 NEC §700.12
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Which recessed luminaire may be installed in direct contact with thermal insulation?
- a.Only fluorescent recessed luminaires
- b.No recessed luminaire may ever be near insulation
- c.A luminaire that is identified and marked as Type IC✓
- d.Any recessed can may touch insulation
Section 410.116 permits only recessed luminaires identified and marked Type IC (Insulation Contact) to be installed in direct contact with thermal insulation. Non-IC luminaires must keep insulation at least 3 inches away, regardless of the lamp type used.2023 NEC §410.116
When may a luminaire be used as a raceway for circuit conductors?
- a.It is never permitted
- b.Any luminaire may be used as a raceway
- c.Only luminaires listed and marked for use as a raceway may carry pass-through conductors✓
- d.Only in commercial buildings
Section 410.64 permits luminaires to be used as a raceway for circuit conductors only where they are listed and marked for use as a raceway, or where they are designed for end-to-end connection to form a continuous raceway, or where conductors pass through as allowed. Using an ordinary luminaire not so listed as a raceway is prohibited.2023 NEC §410.64
Where is track lighting not permitted to be installed?
- a.Anywhere it may be freely installed
- b.Only outdoors
- c.Only within 3 feet of a shower stall
- d.In wet or damp locations, within 5 feet of a bathtub rim, or where concealed✓
Section 410.151(C) prohibits track lighting in wet or damp locations, within 5 feet horizontally of a bathtub rim, where subject to physical damage, where concealed, or where extended through walls or partitions, among other locations. Track lighting is not a general-purpose method that may be freely installed anywhere.2023 NEC §410.151
How must emergency unit equipment (self-contained battery luminaires) be supplied?
- a.Kept portable and unplugged when not in use
- b.Permanently fixed and, for unit equipment, supplied from the same branch circuit as the normal area lighting, connected ahead of any local switch✓
- c.Fed from any random branch circuit
- d.Fed only from the standby generator
Section 700.12 requires emergency unit equipment to be permanently fixed in place and supplied from the branch circuit serving the normal lighting in the same area, connected ahead of any local switches. This ensures the battery unit sees a loss of normal power the moment lighting in that space is lost.2023 NEC §700.12
What GFCI requirement applies to an underwater pool luminaire operating above the low-voltage contact limit?
- a.Underwater luminaires operating over the low-voltage contact limit (over 15 volts) must have GFCI protection✓
- b.GFCI is required only for 120-volt units
- c.GFCI is never required for underwater luminaires
- d.GFCI is required only for spas, not pools
Section 680.23(A)(3) requires ground-fault circuit-interrupter protection for underwater luminaires supplied at more than the low-voltage contact limit (over 15 volts). This protects swimmers from shock; the requirement is not limited to 120-volt units and is not exclusive to spas.2023 NEC §680.23