CSLB
Contractors State License Board, issues licenses.
Getting Started: Exam Overview
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CSLB C-10 Electrical Contractor — key terms, tricks & tips
Everything from the course in one searchable place: 276 entries. Use it to review before a practice test or look up a word you forgot.
276 results
C-10 License
Electrical Contractor license in California.
Getting Started: Exam Overview
CEC
California Electrical Code, based on NEC.
Getting Started: Exam Overview
NEC
National Electrical Code, standard for electrical safety.
Getting Started: Exam Overview
Weighting
Proportion of exam questions from a topic.
Getting Started: Exam Overview
Open Book Exam
Exam where reference materials are allowed.
Getting Started: Exam Overview
CSLB C-10 Exam Structure and Content
To remember the main exam sections: 'PlaRFiST' - Planning, Rough, Finish, Startup, Safety. It sounds like 'blast' for passing the exam!
Getting Started: Exam Overview
CSLB C-10 Exam Structure and Content
The CSLB C-10 Electrical Contractor exam is based on the California Electrical Code (CEC), which is the 2020 edition of the National Electrical Code (NEC) with California amendments. Be sure to use the correct code book for study.
Getting Started: Exam Overview
CSLB C-10 Exam Structure and Content
Underestimating the importance of the 'Planning and Estimation' section, which often carries the highest weight.
Getting Started: Exam Overview
CSLB C-10 Exam Structure and Content
Failing to practice navigating the CEC efficiently, leading to wasted time during the open-book exam.
Getting Started: Exam Overview
CSLB C-10 Exam Structure and Content
Neglecting calculation problems, assuming they are minor, when they are frequently tested and require precision.
Getting Started: Exam Overview
Article
A major division within a CEC chapter, covering a specific topic.
Getting Started: Exam Overview
Section
A detailed subdivision within a CEC article, providing specific rules.
Getting Started: Exam Overview
Amendment
A modification or addition made by California to the NEC text.
Getting Started: Exam Overview
Table of Contents
List of chapters and articles at the front of the code book.
Getting Started: Exam Overview
Index
Alphabetical list of keywords and topics at the back of the code book.
Getting Started: Exam Overview
Navigating the California Electrical Code (CEC)
To remember the order: Chapters, Articles, Sections: 'C-A-S' for 'Code A-Z Search'.
Getting Started: Exam Overview
Navigating the California Electrical Code (CEC)
The CSLB C-10 exam will test your ability to look up specific code requirements. Memorize the general layout (Chapters, Articles, Sections) and practice using both the Table of Contents and the Index to find information quickly. Pay special attention to questions that specify 'California Electrical Code' as these might imply a unique California amendment.
Getting Started: Exam Overview
Navigating the California Electrical Code (CEC)
Relying solely on memory instead of looking up the code, especially for specific numbers or exceptions.
Getting Started: Exam Overview
Navigating the California Electrical Code (CEC)
Ignoring California amendments, assuming the NEC rule is always sufficient.
Getting Started: Exam Overview
Navigating the California Electrical Code (CEC)
Not using the Index effectively, leading to wasted time searching for information.
Getting Started: Exam Overview
Demand Factor
Ratio of maximum demand to total connected load.
Planning & Estimating Essentials
Connected Load
Sum of the continuous ratings of all equipment.
Planning & Estimating Essentials
Service Load
Total electrical load the service entrance must supply.
Planning & Estimating Essentials
VA/sq ft
Volt-amperes per square foot, used for general lighting/receptacles.
Planning & Estimating Essentials
Standard Method
Detailed NEC method for load calculations (Article 220, Part III).
Planning & Estimating Essentials
Optional Method
Simplified NEC method for residential loads (Article 220, Part IV).
Planning & Estimating Essentials
Fixed Appliance
Permanently connected or fastened in place appliance.
Planning & Estimating Essentials
Continuous Load
Load where maximum current is expected for 3+ hours.
Planning & Estimating Essentials
Residential and Commercial Load Calculations
To remember demand factors: 'D' for Demand, 'D' for Discount. You're getting a discount on the total connected load because not everything runs at once!
Planning & Estimating Essentials
Residential and Commercial Load Calculations
The CSLB C-10 exam will test your ability to apply NEC Article 220 for both residential and commercial load calculations. Pay close attention to the specific VA/sq ft values and demand factors found in NEC Tables 220.12, 220.42, 220.55, and 220.56, as these are frequently tested.
Planning & Estimating Essentials
Residential and Commercial Load Calculations
Forgetting to apply demand factors, leading to oversized and expensive services.
Planning & Estimating Essentials
Residential and Commercial Load Calculations
Using residential demand factors for commercial applications, or vice-versa.
Planning & Estimating Essentials
Residential and Commercial Load Calculations
Not accounting for continuous loads by multiplying by 125% when required by NEC 210.20(A) and 215.2(A)(1).
Planning & Estimating Essentials
Service Entrance Conductors
Conductors from service point to service disconnecting means.
Planning & Estimating Essentials
Feeder Conductors
Conductors between service disconnect and branch circuit OCPDs.
Planning & Estimating Essentials
Ampacity
Maximum current a conductor can carry continuously without exceeding its temperature rating.
Planning & Estimating Essentials
Voltage Drop
Reduction in voltage along a conductor due to its resistance.
Planning & Estimating Essentials
Derating
Reducing a conductor's ampacity due to ambient temperature or number of conductors.
Planning & Estimating Essentials
Conduit Fill
Maximum percentage of a conduit's cross-sectional area allowed for conductors.
Planning & Estimating Essentials
Circular Mil (CM)
Unit of area for conductors, equal to the area of a circle 1 mil in diameter.
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
To size conductors, remember 'CALM': **C**ontinuous loads (125%), **A**mpacity tables, **L**ength (voltage drop), **M**aterial (copper/aluminum).
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
The CSLB exam frequently tests on conductor sizing for residential services (e.g., 100A, 200A) and voltage drop calculations. Pay close attention to the 125% rule for continuous loads and the recommended 3% voltage drop for feeders.
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
Forgetting to apply the 125% rule for continuous loads when calculating feeder or service size.
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
Neglecting to derate conductor ampacity for high ambient temperatures or too many conductors in a raceway.
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
Failing to calculate voltage drop, leading to undersized conductors for long runs.
Planning & Estimating Essentials
Service Sizing and Feeder Requirements
Incorrectly calculating conduit fill, resulting in an inability to pull conductors or overheating.
Planning & Estimating Essentials
Material Takeoff
Quantifying all materials needed from blueprints.
Planning & Estimating Essentials
Cost Estimation
Predicting total project expenses, including materials & labor.
Planning & Estimating Essentials
Direct Costs
Expenses directly tied to a project: materials and labor.
Planning & Estimating Essentials
Overhead
Indirect business expenses not tied to specific projects.
Planning & Estimating Essentials
Profit Margin
Percentage of revenue remaining after all costs are paid.
Planning & Estimating Essentials
Labor Units
Standardized time estimates for specific installation tasks.
Planning & Estimating Essentials
Bid
A formal proposal and price quoted for a project.
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
To estimate costs, think 'M-L-O-P': Materials, Labor, Overhead, Profit. It's the recipe for a successful bid!
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
The CSLB exam frequently tests your understanding of the components of a bid and the importance of accurate estimation for business success. While specific numbers aren't usually tested, the process and categories (materials, labor, overhead, profit) are key. Remember that California contractors must provide a written contract for projects over $500, which includes the total price.
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
Forgetting to account for waste or damaged materials, leading to re-orders.
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
Underestimating labor hours due to unforeseen site conditions or project complexity.
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
Not including all fittings, connectors, or miscellaneous hardware in the takeoff.
Planning & Estimating Essentials
Material Takeoffs and Cost Estimation
Failing to factor in overhead costs, leading to an unprofitable project even if direct costs are covered.
Planning & Estimating Essentials
Blueprint
Detailed technical drawing for construction.
Planning & Estimating Essentials
Legend
Key defining symbols and abbreviations on a drawing.
Planning & Estimating Essentials
Floor Plan
Overhead view showing room layout and device placement.
Planning & Estimating Essentials
Electrical Plan
Blueprint showing wiring, devices, and panel locations.
Planning & Estimating Essentials
Reflected Ceiling Plan (RCP)
Shows ceiling-mounted items like lights and detectors.
Planning & Estimating Essentials
Symbol
Standardized graphic for an electrical component.
Planning & Estimating Essentials
Title Block
Information block on a drawing with project details.
Planning & Estimating Essentials
Blueprint Reading and Electrical Symbols
To remember the importance of the Legend: 'L' for Legend, 'L' for Look it up! Never guess what a symbol means.
Planning & Estimating Essentials
Blueprint Reading and Electrical Symbols
The CSLB exam frequently includes questions on identifying specific electrical symbols and interpreting basic circuit paths on simplified floor plans. Pay close attention to symbols for receptacles, switches, and lighting, and recall the specific California Electrical Code requirements for their placement and protection (e.g., GFCI/AFCI locations).
Planning & Estimating Essentials
Blueprint Reading and Electrical Symbols
Not checking the legend for unique project symbols or abbreviations.
Planning & Estimating Essentials
Blueprint Reading and Electrical Symbols
Failing to cross-reference blueprint details with current CEC requirements.
Planning & Estimating Essentials
Blueprint Reading and Electrical Symbols
Assuming all dashed lines represent the same type of wiring or conduit.
Planning & Estimating Essentials
AWG
American Wire Gauge, a standard for conductor sizes.
Wiring Methods & Materials Deep Dive
kcmil
Thousand circular mils, unit for larger conductor sizes.
Wiring Methods & Materials Deep Dive
Temperature Rating
Maximum operating temperature of conductor insulation or equipment terminals.
Wiring Methods & Materials Deep Dive
Correction Factor
Multiplier for ambient temperature variations (NEC 310.15(B)(1)).
Wiring Methods & Materials Deep Dive
Adjustment Factor
Multiplier for more than three current-carrying conductors (NEC 310.15(C)(1)).
Wiring Methods & Materials Deep Dive
OCPD
Overcurrent Protective Device (e.g., circuit breaker, fuse).
Wiring Methods & Materials Deep Dive
Conductor Ampacity and Sizing (NEC 310.15)
To remember the order of applying factors: 'T.A.D.' - Temperature, then Adjustment, then Derating (if needed).
Wiring Methods & Materials Deep Dive
Conductor Ampacity and Sizing (NEC 310.15)
The CSLB exam frequently tests your ability to apply correction and adjustment factors. Pay close attention to ambient temperature values and the number of current-carrying conductors given in the problem. Remember that California uses the CEC, which is based on the NEC 2020.
Wiring Methods & Materials Deep Dive
Conductor Ampacity and Sizing (NEC 310.15)
Forgetting to apply correction factors for ambient temperature or number of conductors.
Wiring Methods & Materials Deep Dive
Conductor Ampacity and Sizing (NEC 310.15)
Ignoring the lowest temperature rating of equipment terminals (NEC 110.14(C)) when determining the usable ampacity column.
Wiring Methods & Materials Deep Dive
Conductor Ampacity and Sizing (NEC 310.15)
Confusing the 90°C ampacity column with the actual usable ampacity after derating and terminal limitations.
Wiring Methods & Materials Deep Dive
Raceway
Enclosed channel for wires, cables, or busbars.
Wiring Methods & Materials Deep Dive
Box Fill
Maximum allowable volume of conductors and devices in an electrical box.
Wiring Methods & Materials Deep Dive
EMT
Electrical Metallic Tubing; a common type of raceway.
Wiring Methods & Materials Deep Dive
RMC
Rigid Metal Conduit; heavy-duty raceway.
Wiring Methods & Materials Deep Dive
NEC Chapter 9, Table 4
Provides allowable percentage fill area for conduits.
Wiring Methods & Materials Deep Dive
NEC Chapter 9, Table 5
Provides cross-sectional area of conductors.
Wiring Methods & Materials Deep Dive
NEC 314.16(B)
Section detailing box fill calculation rules.
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
To remember box fill allowances: 'Grounded Conductors Get One Group.' (All grounding conductors count as a single volume allowance.)
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
The California Electrical Code (CEC) adopts NEC 2020 without significant amendments to the core rules for conduit fill (NEC 310.15(C)(1)) and box fill (NEC 314.16(B)). On the exam, always refer to the specific tables and sections in the NEC for conductor areas, conduit capacities, and box volume allowances. Keywords to spot are 'maximum number of conductors,' 'minimum box volume,' or 'conduit size required.'
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
Forgetting to include the equipment grounding conductor in conduit fill calculations.
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
Incorrectly counting grounding conductors (counting each individually instead of as one allowance) for box fill.
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
Using the wrong fill percentage (e.g., 31% for three or more conductors) for conduit fill.
Wiring Methods & Materials Deep Dive
Raceways, Conduit Fill, and Box Fill Calculations
Not factoring in device straps, internal clamps, or support fittings for box fill.
Wiring Methods & Materials Deep Dive
NM-B Cable
Nonmetallic-sheathed cable, common in residential dry locations.
Wiring Methods & Materials Deep Dive
MC Cable
Metal-clad cable, versatile, used in commercial/industrial/residential.
Wiring Methods & Materials Deep Dive
AC Cable
Armored cable, flexible metallic armor with bonding strip for grounding.
Wiring Methods & Materials Deep Dive
Plenum Space
Air-handling space in buildings, requires specific fire-rated materials.
Wiring Methods & Materials Deep Dive
Bonding Strip
Internal conductor in AC cable ensuring armor is grounded.
Wiring Methods & Materials Deep Dive
Equipment Grounding Conductor
Path for fault current to safely return to the source.
Wiring Methods & Materials Deep Dive
CEC 2022
California Electrical Code, based on NEC 2020 with CA amendments.
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
Remember 'NM for Nests, MC for Malls, AC for Armor.' NM is good for residential 'nests,' MC for versatile 'malls' (commercial), and AC has a protective 'armor.'
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
The California Electrical Code (CEC) adopts the NEC with specific amendments. Pay close attention to local amendments regarding cable types, especially for multi-family dwellings or specific commercial installations. The CSLB exam will test your knowledge of general NEC rules as adopted by the CEC.
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
Using NM-B cable in wet or damp locations, or in commercial/industrial settings where it's prohibited.
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
Confusing the grounding capabilities of MC and AC cable, especially regarding the internal bonding strip in AC.
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
Failing to provide adequate mechanical protection for exposed NM-B cable runs.
Wiring Methods & Materials Deep Dive
Cable Types: NM, MC, AC, and Their Applications
Using non-plenum rated cables in air-handling plenum spaces.
Wiring Methods & Materials Deep Dive
Grounding
Connecting an electrical system or equipment to the earth.
Wiring Methods & Materials Deep Dive
Bonding
Connecting metallic parts to form a continuous, low-impedance path.
Wiring Methods & Materials Deep Dive
Grounding Electrode System
The components that provide the connection to the earth.
Wiring Methods & Materials Deep Dive
Grounding Electrode Conductor (GEC)
Connects the grounding electrode to the service equipment.
Wiring Methods & Materials Deep Dive
Equipment Grounding Conductor (EGC)
Provides a fault current path for non-current-carrying metal parts.
Wiring Methods & Materials Deep Dive
Grounded Conductor
The neutral conductor, normally carries current and is intentionally grounded.
Wiring Methods & Materials Deep Dive
Main Bonding Jumper
Connects the grounded conductor and the equipment grounding conductor at the service.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
GEC, EGC, GEC! Grounding Electrode Conductor goes to Earth. Equipment Grounding Conductor protects Equipment.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
The California Electrical Code (CEC) adopts NEC Article 250 with minimal state-specific amendments. Pay close attention to the requirements for grounding electrode systems, particularly the use of ground rods and the conditions under which two are required (NEC 250.53(A)(2)). Also, remember the distinction between grounding and bonding for the exam.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
Confusing the grounded (neutral) conductor with the equipment grounding conductor (EGC). The neutral carries normal current; the EGC carries fault current.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
Improperly bonding the neutral and ground in a subpanel. The neutral must be isolated from the panel enclosure in subpanels.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
Not installing a proper grounding electrode system or failing to bond all required metallic systems.
Wiring Methods & Materials Deep Dive
Grounding and Bonding Principles (NEC 250)
Assuming a single ground rod is sufficient without verifying its resistance to earth (25 ohms or less).
Wiring Methods & Materials Deep Dive
Busway
Prefabricated enclosure with busbars for power distribution.
Wiring Methods & Materials Deep Dive
Flat Conductor Cable (FCC)
Low-profile cable for under-carpet installations.
Wiring Methods & Materials Deep Dive
Underfloor Raceway
Raceway system embedded in floor for wiring.
Wiring Methods & Materials Deep Dive
Temporary Installation
Electrical wiring for a limited duration, e.g., construction.
Wiring Methods & Materials Deep Dive
Critical Operations Power Systems (COPS)
Power systems for facilities vital to national security/public safety.
Wiring Methods & Materials Deep Dive
Plug-in Unit
Device for connecting loads to a busway system.
Wiring Methods & Materials Deep Dive
AHJ
Authority Having Jurisdiction, enforces code compliance.
Wiring Methods & Materials Deep Dive
Special Wiring Methods and Installations
Think 'B-F-U-T-C': Busways, FCC, Underfloor, Temporary, COPS – these are the special guys!
Wiring Methods & Materials Deep Dive
Special Wiring Methods and Installations
The California Electrical Code (CEC) adopts NEC Articles 368, 328, 390, 590, and 708 without significant state amendments for general application. However, always check local amendments for specific city or county requirements, especially for temporary installations or critical infrastructure projects. Pay close attention to support intervals for busways and duration limits for temporary power.
Wiring Methods & Materials Deep Dive
Special Wiring Methods and Installations
Underestimating the importance of grounding and overcurrent protection for temporary installations.
Wiring Methods & Materials Deep Dive
Special Wiring Methods and Installations
Failing to protect FCC from physical damage or installing it on an unsuitable surface.
Wiring Methods & Materials Deep Dive
Special Wiring Methods and Installations
Not adhering to the specified support intervals for busways, leading to potential structural issues.
Wiring Methods & Materials Deep Dive
Ohm's Law
V=IR; relationship between voltage, current, resistance.
Electrical Theory & Calculations
Voltage (V)
Electrical potential difference, measured in volts.
Electrical Theory & Calculations
Current (I)
Flow rate of electric charge, measured in amperes.
Electrical Theory & Calculations
Resistance (R)
Opposition to current flow, measured in ohms.
Electrical Theory & Calculations
Power (P)
Rate of energy transfer or consumption, measured in watts.
Electrical Theory & Calculations
Watt (W)
Unit of electrical power.
Electrical Theory & Calculations
Ampere (A)
Unit of electrical current.
Electrical Theory & Calculations
Ohm (Ω)
Unit of electrical resistance.
Electrical Theory & Calculations
Ohm's Law and Power Formula Applications
To remember Ohm's Law, think of 'VIR' - Voltage Is Resistance times Current. For Power, think 'PIV' - Power Is Voltage times Current.
Electrical Theory & Calculations
Ohm's Law and Power Formula Applications
The CSLB C-10 exam frequently tests your ability to apply Ohm's Law and the Power Formula to calculate circuit parameters. Pay close attention to load calculations (e.g., for motors, heaters) and how they relate to conductor sizing and overcurrent protection, as per CEC/NEC Articles 210 and 220.
Electrical Theory & Calculations
Ohm's Law and Power Formula Applications
Confusing the units (e.g., using watts for current, or ohms for voltage).
Electrical Theory & Calculations
Ohm's Law and Power Formula Applications
Incorrectly transposing the formulas (e.g., V = I/R instead of V = IR).
Electrical Theory & Calculations
Ohm's Law and Power Formula Applications
Forgetting to account for continuous loads (80% rule) when sizing circuits for power calculations.
Electrical Theory & Calculations
Series Circuit
Components connected end-to-end, single current path.
Electrical Theory & Calculations
Parallel Circuit
Components connected across same points, multiple current paths.
Electrical Theory & Calculations
Combination Circuit
Contains both series and parallel connections.
Electrical Theory & Calculations
Equivalent Resistance
Single resistance that can replace a complex circuit section.
Electrical Theory & Calculations
Kirchhoff's Voltage Law
Sum of voltage drops in a series loop equals source voltage.
Electrical Theory & Calculations
Kirchhoff's Current Law
Total current entering a parallel junction equals total current leaving.
Electrical Theory & Calculations
Series, Parallel, and Combination Circuits
For series circuits, remember 'Same Current, Sum Resistance, Sum Voltage.' For parallel, 'Same Voltage, Sum Current, Reciprocal Resistance.'
Electrical Theory & Calculations
Series, Parallel, and Combination Circuits
The CSLB C-10 exam expects you to apply Ohm's Law and power formulas (P=IV, P=I^2R, P=V^2/R) to series, parallel, and combination circuits to find unknown values like total resistance, current through a specific component, or voltage across a load. Pay close attention to units (Volts, Amps, Ohms, Watts).
Electrical Theory & Calculations
Series, Parallel, and Combination Circuits
Incorrectly applying series resistance formula to parallel circuits, or vice-versa.
Electrical Theory & Calculations
Series, Parallel, and Combination Circuits
Forgetting that voltage is constant across parallel branches, and current is constant in series branches.
Electrical Theory & Calculations
Series, Parallel, and Combination Circuits
Failing to simplify combination circuits step-by-step, leading to calculation errors.
Electrical Theory & Calculations
Single-Phase Power
One alternating current, pulsating power delivery.
Electrical Theory & Calculations
Three-Phase Power
Three alternating currents, 120° out of phase, constant power.
Electrical Theory & Calculations
Wye Connection
Transformer configuration with common neutral, V_line = √3 * V_phase.
Electrical Theory & Calculations
Delta Connection
Transformer configuration in a loop, V_line = V_phase.
Electrical Theory & Calculations
Transformer
Device transferring electrical energy via induction, changes voltage.
Electrical Theory & Calculations
Primary Winding
Input coil of a transformer.
Electrical Theory & Calculations
Secondary Winding
Output coil of a transformer.
Electrical Theory & Calculations
High-Leg Delta
Delta system with one phase 208V to neutral.
Electrical Theory & Calculations
Three-Phase Systems and Transformer Basics
Wye-Y-I: 'Why' is for 'Y' (Wye), and 'I' (current) is the same. Delta-D-V: 'D'elta has 'D'ifferent things, but 'V' (voltage) is the same.
Electrical Theory & Calculations
Three-Phase Systems and Transformer Basics
The CSLB exam frequently tests knowledge of Wye vs. Delta connections, especially voltage and current relationships. Memorize that for Wye, V_line = √3 * V_phase and I_line = I_phase. For Delta, V_line = V_phase and I_line = √3 * I_phase. Also, know the specific voltages for a high-leg Delta system (120/240V, with one leg at 208V to ground).
Electrical Theory & Calculations
Three-Phase Systems and Transformer Basics
Confusing line voltage/current with phase voltage/current, especially in Wye and Delta systems. Always remember the √3 factor.
Electrical Theory & Calculations
Three-Phase Systems and Transformer Basics
Connecting 120V loads to the 'high leg' of a Delta system, leading to immediate equipment damage due to overvoltage.
Electrical Theory & Calculations
Three-Phase Systems and Transformer Basics
Ignoring transformer efficiency and power factor in calculations, which can lead to undersized equipment or overloaded systems.
Electrical Theory & Calculations
Resistivity (K)
Material's resistance to current flow.
Electrical Theory & Calculations
Circular Mils (CM)
Unit of conductor cross-sectional area.
Electrical Theory & Calculations
NEC 210.19(A)(4)
Code section recommending voltage drop limits.
Electrical Theory & Calculations
Branch Circuit
Circuit from last overcurrent device to outlets.
Electrical Theory & Calculations
Feeder
Conductors between service equipment and branch circuit OCPD.
Electrical Theory & Calculations
Conductor Gauge
Wire size, inversely related to AWG number.
Electrical Theory & Calculations
Voltage Drop Calculations (NEC 210.19(A)(4))
VD = 'Very Dangerous' (2) KIL (Kill) CM (Circuits Monthly) for single-phase, or 'Very Dangerous' (1.732) KIL (Kill) CM (Circuits Monthly) for three-phase.
Electrical Theory & Calculations
Voltage Drop Calculations (NEC 210.19(A)(4))
The California Electrical Code (CEC) adopts NEC 210.19(A)(4) directly. The exam may present scenarios where you need to calculate voltage drop and determine if it meets the recommended 3% for branch circuits or 5% for combined feeders and branch circuits. Memorize the K factors for copper (12.9) and aluminum (21.2) and the single-phase and three-phase formulas.
Electrical Theory & Calculations
Voltage Drop Calculations (NEC 210.19(A)(4))
Forgetting to double the length (L) for single-phase calculations, as current travels to and from the load.
Electrical Theory & Calculations
Voltage Drop Calculations (NEC 210.19(A)(4))
Using the wrong K factor for copper vs. aluminum, or for different operating temperatures.
Electrical Theory & Calculations
Voltage Drop Calculations (NEC 210.19(A)(4))
Confusing single-phase and three-phase voltage drop formulas, especially the constant multiplier.
Electrical Theory & Calculations
Panelboard
Single panel or group of panels with buses and OCPDs.
Equipment & Installation Standards
Switchboard
Large assembly of panels with switches, OCPDs, and buses.
Equipment & Installation Standards
Working Space
Clear area required around electrical equipment for safety.
Equipment & Installation Standards
Condition 1
Working space with exposed live parts on one side only.
Equipment & Installation Standards
Condition 2
Working space with exposed live parts on one side, grounded on other.
Equipment & Installation Standards
Condition 3
Working space with exposed live parts on both sides.
Equipment & Installation Standards
Busbar
Heavy conductor for collecting and distributing electric current.
Equipment & Installation Standards
Panelboards and Switchboards Installation
Think '3-3.5-4' for working depth: 3 feet (Condition 1), 3.5 feet (Condition 2), 4 feet (Condition 3).
Equipment & Installation Standards
Panelboards and Switchboards Installation
The California Electrical Code (CEC) adopts NEC Article 110.26 for working space requirements without significant amendment. Pay close attention to the minimum depth requirements based on voltage to ground and the three conditions.
Equipment & Installation Standards
Panelboards and Switchboards Installation
Failing to provide adequate working space in front of, above, and to the sides of electrical equipment.
Equipment & Installation Standards
Panelboards and Switchboards Installation
Not sealing unused knockout openings in enclosures, leading to potential hazards or equipment damage.
Equipment & Installation Standards
Panelboards and Switchboards Installation
Incorrectly assuming that only the depth of working space matters, neglecting width and headroom requirements.
Equipment & Installation Standards
Overcurrent
Any current exceeding the rated current of equipment or the ampacity of a conductor.
Equipment & Installation Standards
Overload
Operation of equipment in excess of its normal, full-load rating.
Equipment & Installation Standards
Short Circuit
An abnormal connection of low resistance between two points of different potential.
Equipment & Installation Standards
Selective Coordination
Localization of an overcurrent condition to restrict outages to the circuit involved.
Equipment & Installation Standards
Inverse-Time Breaker
A circuit breaker with a trip time inversely proportional to the magnitude of the overcurrent.
Equipment & Installation Standards
Overcurrent Protection Devices (OCPDs)
To remember OCPD rules: 'C.A.F.S.' - Continuous loads are 125%, Ampacity of conductors, Fuse or breaker, Selective coordination.
Equipment & Installation Standards
Overcurrent Protection Devices (OCPDs)
The California Electrical Code (CEC) adopts NEC Article 240 for overcurrent protection. Pay close attention to the 125% rule for continuous loads (NEC 210.20(A) and 215.2(A)(1)) and motor circuit OCPD sizing (NEC 430.52). These are frequently tested.
Equipment & Installation Standards
Overcurrent Protection Devices (OCPDs)
Sizing the OCPD exactly to the continuous load instead of applying the 125% rule.
Equipment & Installation Standards
Overcurrent Protection Devices (OCPDs)
Ignoring correction and adjustment factors when determining conductor ampacity, leading to undersized conductors or oversized OCPDs.
Equipment & Installation Standards
Overcurrent Protection Devices (OCPDs)
Not understanding that motor OCPD sizing can be higher than conductor ampacity due to starting current, as long as overload protection is present.
Equipment & Installation Standards
GFCI
Ground-Fault Circuit Interrupter; protects against electric shock.
Equipment & Installation Standards
AFCI
Arc-Fault Circuit Interrupter; protects against electrical fires.
Equipment & Installation Standards
Ground Fault
Unintended path for current to flow to ground.
Equipment & Installation Standards
Arc Fault
Dangerous electrical discharge causing high heat.
Equipment & Installation Standards
Dwelling Unit
A single unit providing complete living facilities for one or more persons.
Equipment & Installation Standards
Receptacle
A contact device installed at the outlet for the connection of an attachment plug.
Equipment & Installation Standards
GFCI and AFCI Requirements and Locations
GFCIs Guard Guys from Ground, AFCIs Arrest Arcs from igniting Anything.
Equipment & Installation Standards
GFCI and AFCI Requirements and Locations
The CSLB exam frequently tests specific GFCI/AFCI locations. Memorize the list of required GFCI locations (e.g., bathrooms, garages, outdoors, kitchens for countertops, within 6ft of sinks) and the broad AFCI requirements for dwelling unit living spaces. Pay attention to the voltage and amperage (125V, 15A/20A).
Equipment & Installation Standards
GFCI and AFCI Requirements and Locations
Failing to install GFCI protection in all required wet/damp locations.
Equipment & Installation Standards
GFCI and AFCI Requirements and Locations
Omitting AFCI protection in required dwelling unit areas, assuming only bedrooms need it.
Equipment & Installation Standards
GFCI and AFCI Requirements and Locations
Confusing the purpose of GFCI (shock) with AFCI (fire).
Equipment & Installation Standards
Full-Load Current (FLA)
Current drawn by a motor operating at rated HP and voltage.
Equipment & Installation Standards
Service Factor (SF)
Multiplier indicating a motor's ability to handle overload.
Equipment & Installation Standards
Disconnecting Means
Device to safely isolate a motor from its power source.
Equipment & Installation Standards
Motor Controller
Device that starts, stops, and regulates a motor.
Equipment & Installation Standards
Overload Protection
Protects motor from sustained overcurrents and overheating.
Equipment & Installation Standards
Branch-Circuit OCPD
Protects conductors and motor from short circuits/ground faults.
Equipment & Installation Standards
Inverse Time Circuit Breaker
OCPD that trips faster with higher current.
Equipment & Installation Standards
Non-Time Delay Fuse
OCPD that opens quickly on overcurrent.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
For 'Conductor Sizing,' remember 'C-125': Conductors need 125% of FLA. For 'Overload Protection,' remember 'O-115/125': Overloads are 115% or 125% of FLA.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
The CEC adopts NEC Article 430 for motors. Pay close attention to the specific tables referenced for FLA (430.248, 430.250), conductor sizing (430.22), and OCPD sizing (430.52). The 125% rule for conductors and the various percentages for OCPDs and overload protection are frequently tested.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
Under-sizing conductors, leading to overheating and voltage drop.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
Incorrectly sizing the branch-circuit OCPD, causing nuisance tripping or inadequate protection.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
Confusing branch-circuit short-circuit/ground-fault protection with motor overload protection; they serve different purposes.
Equipment & Installation Standards
Motors, Motor Circuits, and Controls
Not using the motor's nameplate FLA or the correct CEC table for calculations.
Equipment & Installation Standards
Cal/OSHA
California Occupational Safety and Health Administration.
Safety & Testing Protocols
T8 CCR
Title 8 of the California Code of Regulations.
Safety & Testing Protocols
Electrical Safety Orders (ESOs)
Specific Cal/OSHA regulations governing electrical work.
Safety & Testing Protocols
Arc Flash
Sudden release of electrical energy, causing extreme heat and light.
Safety & Testing Protocols
Lockout/Tagout
Procedure to ensure circuits are de-energized before work.
Safety & Testing Protocols
Cal/OSHA Electrical Safety Regulations
Think 'CALifornia's 8 'T's for Safety': Title 8, Training, Tools, Tagout, Testing, Teamwork, T8 CCR, and Technical (CEC) compliance!
Safety & Testing Protocols
Cal/OSHA Electrical Safety Regulations
The CSLB exam emphasizes Cal/OSHA's role in enforcing safety standards for electrical contractors. Memorize that Cal/OSHA regulations are found in Title 8 (T8 CCR) and often reference the California Electrical Code (CEC) for technical specifics.
Safety & Testing Protocols
Cal/OSHA Electrical Safety Regulations
Assuming NEC compliance automatically means Cal/OSHA compliance; Cal/OSHA has specific additions or stricter requirements.
Safety & Testing Protocols
Cal/OSHA Electrical Safety Regulations
Neglecting to provide specific Cal/OSHA-mandated training, even if workers are experienced.
Safety & Testing Protocols
Cal/OSHA Electrical Safety Regulations
Failing to document safety procedures, training, and inspections, which Cal/OSHA requires.
Safety & Testing Protocols
Lockout
Physical placement of a lock to prevent energy isolation device operation.
Safety & Testing Protocols
Tagout
Placement of a warning tag on an energy isolating device.
Safety & Testing Protocols
Energy Isolating Device
A mechanical device that physically prevents energy transmission.
Safety & Testing Protocols
Authorized Employee
Employee who locks out or tags out equipment for servicing.
Safety & Testing Protocols
Affected Employee
Employee who operates or works near LOTO equipment.
Safety & Testing Protocols
Stored Energy
Residual energy (e.g., hydraulic, pneumatic, kinetic) that must be released.
Safety & Testing Protocols
Verification of Isolation
Checking that equipment is de-energized before beginning work.
Safety & Testing Protocols
Lockout/Tagout Procedures and Best Practices
Remember the steps of LOTO with 'S.I.L.V.E.R.': Shutdown, Isolate, Lock/Tag, Verify, Energize (when done), Restore.
Safety & Testing Protocols
Lockout/Tagout Procedures and Best Practices
The CSLB exam expects you to know that Cal/OSHA's LOTO standard is found in Title 8, Section 3314. Pay attention to the specific definitions of 'authorized' and 'affected' employees, and the requirements for LOTO devices.
Safety & Testing Protocols
Lockout/Tagout Procedures and Best Practices
Failing to identify and dissipate all forms of stored energy (e.g., capacitors, compressed air).
Safety & Testing Protocols
Lockout/Tagout Procedures and Best Practices
Not verifying zero energy state with a test instrument after applying LOTO devices.
Safety & Testing Protocols
Lockout/Tagout Procedures and Best Practices
Allowing unauthorized personnel to remove LOTO devices or work on locked-out equipment.
Safety & Testing Protocols
Incident Energy
Amount of thermal energy impressed on a surface at a working distance, measured in cal/cm².
Safety & Testing Protocols
NFPA 70E
Standard for Electrical Safety in the Workplace, covers arc flash and shock.
Safety & Testing Protocols
Arc-Rated (AR) PPE
Personal Protective Equipment designed to protect against arc flash hazards.
Safety & Testing Protocols
Arc Flash Risk Assessment
Process to identify arc flash hazards and determine protective measures.
Safety & Testing Protocols
Arc Blast
Pressure wave generated by an arc flash, causing physical trauma.
Safety & Testing Protocols
Working Distance
Distance from the arc source to the person's face or chest.
Safety & Testing Protocols
NFPA 70E Arc Flash Basics and PPE
To remember the dangers: Heat, Light, Pressure, Projectiles. Think 'HLPP' - 'Help! Live Power Problem!'
Safety & Testing Protocols
NFPA 70E Arc Flash Basics and PPE
The CSLB C-10 exam often tests on the hierarchy of controls for electrical hazards. Remember that eliminating the hazard (de-energizing) is always preferred over using PPE. Also, know that Cal/OSHA enforces NFPA 70E.
Safety & Testing Protocols
NFPA 70E Arc Flash Basics and PPE
Assuming flame-resistant (FR) clothing provides adequate arc flash protection; AR is specifically rated for incident energy.
Safety & Testing Protocols
NFPA 70E Arc Flash Basics and PPE
Not performing an Arc Flash Risk Assessment before working on energized equipment.
Safety & Testing Protocols
NFPA 70E Arc Flash Basics and PPE
Wearing damaged or contaminated PPE, which compromises its protective integrity.
Safety & Testing Protocols
Multimeter
Measures voltage, current, and resistance; versatile diagnostic tool.
Safety & Testing Protocols
Clamp Meter
Measures current non-invasively by clamping around a conductor.
Safety & Testing Protocols
Voltmeter
Measures electrical potential difference (voltage) in parallel.
Safety & Testing Protocols
Ammeter
Measures electrical current flow, connected in series.
Safety & Testing Protocols
Ohmmeter
Measures electrical resistance on de-energized circuits.
Safety & Testing Protocols
Continuity Test
Checks for a complete electrical path; no breaks in a circuit.
Safety & Testing Protocols
Megohmmeter
Measures high insulation resistance to detect breakdown.
Safety & Testing Protocols
CAT Rating
Safety rating for meters, indicating protection against transients.
Safety & Testing Protocols
Electrical Meters and Testing Procedures
V-A-R: Volts-Amps-Resistance. Remember your multimeter measures these three, like a versatile 'VAR'iable tool!
Safety & Testing Protocols
Electrical Meters and Testing Procedures
The CSLB C-10 exam will often present scenarios requiring you to choose the correct meter for a task. Pay close attention to keywords like 'measure current without breaking circuit' (clamp meter) or 'check for insulation breakdown' (megohmmeter). Always prioritize safety procedures like de-energizing before resistance tests.
Safety & Testing Protocols
Electrical Meters and Testing Procedures
Measuring resistance or continuity on an energized circuit, which can damage the meter and pose a shock hazard.
Safety & Testing Protocols
Electrical Meters and Testing Procedures
Using a meter with an insufficient CAT rating for the circuit's voltage and energy levels, risking meter failure and injury.
Safety & Testing Protocols
Electrical Meters and Testing Procedures
Connecting an ammeter in parallel with a voltage source, leading to a short circuit and potential meter damage.
Safety & Testing Protocols
Electrical Meters and Testing Procedures
Clamping a clamp meter around multiple conductors carrying current in opposite directions, resulting in an inaccurate zero reading.
Safety & Testing Protocols