AZ ROC R-11 Electrical flashcards
AZ ROC R-11 Electrical · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Ohm's law
- Voltage equals current times resistance (E = I × R); power equals voltage times current, so P = I²R = E²/R for resistive loads.
- Three-phase power formula
- For a balanced three-phase load, real power equals the square root of three times line voltage times line current times power factor.
- Continuous load sizing
- A continuous load is expected to operate at maximum current for three hours or more; branch-circuit conductors and overcurrent devices are sized at 125 percent of that load.
- Box fill volume
- National Electrical Code box fill counts each 14 AWG conductor as 2.00 cubic inches, each 12 AWG as 2.25 cubic inches, and each 10 AWG as 2.50 cubic inches.
- Wye neutral current
- In a balanced three-phase wye circuit with linear loads, the neutral current is zero; the neutral carries only the unbalanced current when loads differ.
- NM cable support
- Nonmetallic-sheathed cable must be secured within 12 inches of each box and at intervals not exceeding 4.5 feet along the run.
- EMT support spacing
- Electrical metallic tubing must be supported within 3 feet of each box and at intervals not exceeding 10 feet, unless a listed exception applies.
- Conduit fill percentages
- For conduit fill, one conductor may fill 53 percent, two conductors 31 percent, and three or more conductors 40 percent of the conduit interior area.
- Raceway conductor derating
- When 4 to 6 current-carrying conductors share a raceway, ampacity is reduced to 80 percent; 7 to 9 conductors to 70 percent; 10 to 20 to 50 percent.
- Expansion joint fitting
- A listed expansion fitting is required where a raceway crosses a building expansion joint so the conduit can move without buckling or pulling apart.
- Standard breaker sizes
- Common standard overcurrent device ratings include 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, and 100 amperes.
- Ground rod length
- A grounding rod must be at least 8 feet long and driven to full length; multiple rods must be spaced at least 6 feet apart.
- Water pipe supplement
- When a metal underground water pipe is used as a grounding electrode, it must be supplemented by an additional electrode such as a ground rod.
- Equipment grounding conductor
- The equipment grounding conductor provides a low-impedance fault path and is sized from National Electrical Code Table 250.122 based on the overcurrent device rating.
- GFCI trip threshold
- A ground-fault circuit interrupter for personnel protection trips at approximately 5 milliamperes of ground-fault current to reduce electric shock risk.
- Motor conductor sizing
- Motor branch-circuit conductors are sized at 125 percent of the motor full-load current from the National Electrical Code tables, not the nameplate current.
- Motor overload protection
- Motor overload protection is typically sized at 115 to 125 percent of the motor nameplate full-load current and protects the motor from sustained overload.
- Motor disconnect location
- A motor disconnecting means must be within sight of the motor and controller, or capable of being locked open, unless the code permits otherwise.
- NEMA 3R enclosure
- A NEMA 3R enclosure is weather-resistant and rainproof for outdoor use; it protects against falling rain and is not watertight.
- Motor short-circuit protection
- Motor branch short-circuit and ground-fault protection is selected from National Electrical Code Table 430.52; an inverse-time breaker generally may not exceed 250 percent of full-load current.
- Arizona R-11 license
- The Arizona Registrar of Contractors R-11 classification is an electrical contractor license; it authorizes the licensee to contract for electrical work within the scope of that classification.
- A.R.S. Title 32 Chapter 10
- Arizona Revised Statutes Title 32, Chapter 10 governs contractor licensing and regulation by the Arizona Registrar of Contractors, including electrical contractors.
- Unlicensed contracting prohibition
- Arizona law generally prohibits a person from offering or performing contractor work without a valid license; violations can lead to citations, cease-and-desist orders, and civil penalties.
- Statewide journeyman license
- Arizona does not issue a statewide journeyman electrician license; individual cities or towns may require their own electrician registration or license.
- NEC local amendments
- The National Electrical Code is a model code; in Arizona the edition in force and any amendments are set by the adopting jurisdiction and enforced by its authority having jurisdiction.
- Arizona Blue Stake
- Arizona 811, formerly Arizona Blue Stake, must be contacted before excavation so underground utilities can be marked; digging before marks is unsafe and may violate law.
- Markup versus margin
- Markup equals price minus cost divided by cost; margin equals price minus cost divided by price. A 25 percent markup is only a 20 percent margin.
- Labor unit estimating
- Labor cost equals quantity times the labor unit in hours per unit times the loaded hourly rate, including wages, taxes, insurance, and benefits.
- Change order requirement
- A change order documents added or deleted work and should be written and signed by the owner or authorized representative before the changed work proceeds.
- Lockout tagout
- Lockout/tagout isolates hazardous energy with a lock and tag before servicing equipment; only the person who applied the lock should remove it.
- Assured grounding program
- An assured equipment grounding conductor program tests temporary cords, receptacles, and tools for continuity and records the tests at required intervals.
- Critical path method
- The critical path is the longest sequence of dependent project activities; any delay on that path delays the entire project completion date.