CSLB General Building (B) Trade Practice Test
Preguntas frecuentes
¿Cuántas preguntas de práctica de Master Electrician (NEC) hay aquí?+
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Unas 100 preguntas, 300 minutos, y necesitas 75% para aprobar. Practica por tema aquí y luego haz el simulacro cronometrado para medir tu preparación.
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Preguntas de práctica de ejemplo
Algunas preguntas reales de este banco gratuito, con explicaciones completas. Usa la herramienta de arriba para el banco completo.
- 1. Calculations
A single-family dwelling has 2,000 sq ft of habitable floor area. Using the standard calculation method at 3 VA per sq ft, what is the general lighting and general-use receptacle load before any demand factors?
- a.6,000 VA
- b.4,000 VA
- c.8,000 VA
- d.3,000 VA
Respuesta: a
Explicación: General lighting is figured at 3 VA per sq ft: 2,000 sq ft x 3 VA = 6,000 VA. This value is calculated before applying the general-lighting demand factors.
- 2. Calculations
An electric range has a Column C demand of 8,000 VA. Using the 70% neutral demand for ranges, what is the range contribution to the feeder neutral load?
- a.8,000 VA
- b.4,000 VA
- c.7,000 VA
- d.5,600 VA
Respuesta: d
Explicación: The feeder neutral for a household range may be figured at 70% of the range demand: 8,000 x 0.70 = 5,600 VA.
- 3. Calculations
A 208-V three-phase feeder carries 40 A over 150 ft using #6 Cu (CM = 26,240, K = 12.9). What is the approximate voltage drop?
- a.3.0 V
- b.7.2 V
- c.5.1 V
- d.9.0 V
Respuesta: c
Explicación: Three-phase VD = (1.732 x K x I x L) / CM = (1.732 x 12.9 x 40 x 150) / 26,240 = 134,050 / 26,240 = 5.11 V.
- 4. Services & Distribution
A branch circuit is protected by a 100-A overcurrent device. What is the minimum copper equipment grounding conductor?
- a.#10 AWG
- b.#8 AWG
- c.#6 AWG
- d.#4 AWG
Respuesta: b
Explicación: The equipment grounding conductor table requires #8 Cu for an overcurrent device rating up to 100 A.
Fuente: 2023 NEC Table 250.122
- 5. Services & Distribution
What is the minimum service disconnecting-means rating for a one-family dwelling?
- a.100 A
- b.60 A
- c.125 A
- d.200 A
Respuesta: a
Explicación: The service disconnecting means for a one-family dwelling must be rated at least 100 A, 3-wire.
Fuente: 2023 NEC 230.79
- 6. Advanced Wiring
A location where ignitable concentrations of flammable gases or vapors exist under normal operating conditions is classified as:
- a.Class II, Division 1
- b.Class III
- c.Class I, Division 2
- d.Class I, Division 1
Respuesta: d
Explicación: Class I covers flammable gases/vapors; Division 1 means ignitable concentrations can exist under normal operation, so it is Class I, Division 1.
Fuente: 2023 NEC 500.5(B)(1)
- 7. Advanced Wiring
Which nameplate value on an air-conditioning unit is used to size the branch-circuit conductors?
- a.Maximum overcurrent protection
- b.Nameplate horsepower
- c.Minimum circuit ampacity
- d.Rated-load amps only
Respuesta: c
Explicación: Conductors are sized to the marked minimum circuit ampacity (MCA); the maximum overcurrent protective device (MOCP) sizes the breaker or fuse.
Fuente: 2023 NEC 440.4
- 8. Theory & Design
A load draws 80 kW of real power and 100 kVA of apparent power. What is the power factor?
- a.1.0
- b.0.8
- c.0.6
- d.0.9
Respuesta: b
Explicación: Power factor = real power / apparent power = 80 kW / 100 kVA = 0.8.
- 9. Theory & Design
A single-line (one-line) diagram represents an electrical system by:
- a.One line for each circuit or set of conductors
- b.Each individual conductor drawn separately
- c.The physical layout of raceways
- d.Only the branch-circuit wiring
Respuesta: a
Explicación: A one-line diagram uses a single line and standard symbols to represent circuits and equipment, simplifying analysis of the power system.
- 10. Code Admin & Safety
Equipment rated at what current or more requires two entrances to and egress from the working space when the space is large or contains overcurrent devices?
- a.800 A
- b.600 A
- c.1000 A
- d.1200 A
Respuesta: d
Explicación: For equipment rated 1,200 A or more and over 6 ft wide, two entrances/egress paths to the working space are required.
Fuente: 2023 NEC 110.26(C)(2)