CSLB Trade — Electrical (C-10) — All Questions
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62 questions
If a receptacle takes 0.5 labor-hour to install, how many labor-hours should be estimated to install 30 receptacles?
- a.60 hours
- b.30 hours
- c.7.5 hours
- d.15 hours✓
Labor = 30 units × 0.5 hr = 15 labor-hours. Multiplying by 2 (60) or by the count alone (30) misapplies the labor unit, and 7.5 uses the wrong quantity.
Using the optional method, a dwelling's 220.82(B) loads compute to 19,280 VA, plus 5,000 VA of air conditioning at 100%. On a 240 V service (about 101 A), what is the minimum standard service size?
- a.125 A✓
- b.175 A
- c.100 A
- d.150 A
Total = 19,280 + 5,000 = 24,280 VA; 24,280 ÷ 240 = 101 A. Since the demand exceeds 100 A, the next standard size, 125 A, is required. A 100 A service would be slightly undersized.2023 NEC §220.82
The California Electrical Code is essentially the NEC as modified by what?
- a.IEEE standards
- b.Local utility company rules
- c.UL product listings
- d.California state amendments✓
California adopts each NEC edition and then modifies it with California-specific amendments to create the CEC (Title 24, Part 3). Utility rules, IEEE standards, and UL listings are separate documents, not what creates the CEC.
In code language, what does the abbreviation AHJ stand for?
- a.Authority Having Jurisdiction✓
- b.American Home Journal
- c.Annual Home Inspection
- d.Approved Housing Judge
AHJ means Authority Having Jurisdiction, the office or official responsible for enforcing the code and approving equipment and installations. The other choices are not code terms.
For a set of service-entrance conductors, the service disconnecting means is generally limited to a maximum of how many switches or circuit breakers?
- a.6✓
- b.8
- c.4
- d.2
The service disconnecting means is limited to a maximum of six switches or circuit breakers for a given set of service conductors. Modern code also requires them to be in separate enclosures, but the six-disconnect limit still governs.2023 NEC §230.71
The 2023 NEC requires one- and two-family dwellings to have an emergency disconnect installed where?
- a.Inside the dwelling only
- b.In the attic
- c.It is not required
- d.At a readily accessible outdoor location✓
An emergency disconnect must be installed in a readily accessible outdoor location so first responders can shut off power. It is required, and an interior or attic location would not meet the readily accessible outdoor requirement.2023 NEC §230.85
For 120/240 V equipment likely to require examination while energized (Condition 1), what is the minimum depth of working space in front of it?
- a.4 ft
- b.1 ft
- c.2 ft
- d.3 ft✓
Under Condition 1, the minimum working-space depth for equipment operating at 0-150 V to ground is 3 ft. Two feet or one foot is too little, and 4 ft applies to higher-voltage or worse conditions.2023 NEC §110.26(A)(1)
What is the minimum width of working space in front of electrical equipment (or the width of the equipment, whichever is greater)?
- a.30 in✓
- b.18 in
- c.36 in
- d.24 in
The working space must be at least 30 in wide, or the width of the equipment, whichever is greater. Narrower dimensions such as 24 in or 18 in do not meet the minimum.2023 NEC §110.26(A)(2)
What is the minimum headroom (height) of working space about electrical equipment such as panelboards?
- a.6 ft 6 in✓
- b.6 ft 3 in
- c.6 ft
- d.7 ft
The minimum headroom of working space is 6 ft 6 in (or the height of the equipment if taller). The lesser heights do not satisfy the requirement, and 7 ft exceeds the minimum.2023 NEC §110.26(A)(3)
What is the line current of a 30 kVA, three-phase load supplied at 208 V?
- a.100 A
- b.144 A
- c.83 A✓
- d.72 A
For a three-phase load, I = VA ÷ (V × 1.732) = 30,000 ÷ (208 × 1.732) = 30,000 ÷ 360 = 83 A. Dividing by 208 alone or by 120 gives the incorrect single-phase-style results.
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A complete bid price for an electrical project generally consists of which of the following?
- a.Permit fees only
- b.Material only
- c.Labor only
- d.Material, labor, overhead, and profit✓
A full bid adds up direct material, direct labor, overhead (indirect business costs), and profit. Leaving out any of these, such as bidding labor or material alone, would not cover the true cost of doing the work.
The NEC is updated on a three-year cycle. The 2023 NEC directly follows which prior edition?
- a.2017 NEC
- b.There is no prior edition
- c.2014 NEC
- d.2020 NEC✓
On the three-year cycle, the edition immediately before the 2023 NEC is the 2020 NEC. The 2017 and 2014 editions are earlier cycles, not the one directly preceding 2023.