MT Journeyman Electrician flashcards
MT Journeyman Electrician · Build recall with a focused review session.
31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Ohm's law
- The relationship E = I × R, where E is voltage in volts, I is current in amperes, and R is resistance in ohms.
- Three-phase power formula
- P = √3 × E_line × I_line × power factor, used to calculate real power in a balanced three-phase system.
- Voltage drop single-phase
- VD = 2 × K × I × L / CM, where K is the conductor constant, I is current, L is length in feet, and CM is circular mil area.
- NM-B cable use
- Nonmetallic-sheathed cable permitted only in normally dry locations and must be protected from physical damage where required.
- EMT support spacing
- Electrical metallic tubing must be supported within 3 ft of each box and at intervals not exceeding 10 ft.
- Box fill allowance
- Each 12 AWG conductor in a box requires 2.25 cubic inches of volume; each device yoke counts as two conductors.
- Raceway fill 40 percent
- For more than two conductors in a raceway, the total conductor area must not exceed 40% of the raceway internal cross-sectional area.
- Service neutral bonding
- The grounded service conductor must be bonded to the equipment grounding conductor at the service disconnecting means only, not at downstream panels.
- Equipment grounding conductor sizing
- The EGC for a feeder is sized per Table 250.122 based on the rating of the overcurrent device protecting the feeder.
- Standard overcurrent ratings
- Standard device ratings include 15, 20, 30, 40, 50, 60, 70, 80, 100, 110, 125, 150, 175, 200, 225, 250, 300, 400, 500, 600, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes.
- Dwelling general lighting load
- Three volt-amperes per square foot of floor area for general lighting in dwelling units, used in service calculations.
- Small-appliance branch circuit
- A 20-ampere branch circuit in a dwelling unit supplying receptacle outlets in the kitchen, pantry, breakfast room, or dining room; at least two are required.
- Receptacle spacing dwelling
- No point on a wall space may be more than 6 feet from a receptacle outlet; wall spaces wider than 2 feet require a receptacle.
- Motor overload protection
- For a motor with a service factor of 1.15 or more, the overload device must be sized at no more than 125% of the nameplate full-load current.
- Motor branch-circuit protection
- Short-circuit and ground-fault protection for a motor branch circuit is selected from Table 430.52, typically 250% of full-load current for an inverse-time breaker.
- Motor disconnect location
- The motor disconnecting means must be within sight of the motor and capable of being locked in the open position.
- Class I location
- A location where flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
- GFCI bathroom requirement
- All 125-volt, single-phase, 15- and 20-ampere receptacles in dwelling unit bathrooms must have ground-fault circuit-interrupter protection.
- Montana electrical board
- The Montana Board of Electrical Examiners, within the Department of Labor and Industry, administers electrical licensing and adopts the NEC by rule.
- Montana journeyman license
- A journeyman electrician license in Montana requires documented work experience and passing a written examination administered by the board.
- Montana contractor license
- A person engaged in electrical contracting in Montana must hold a contractor's license and employ a licensed master or journeyman electrician.
- Arc flash boundary
- The distance from energized equipment at which a person without arc-rated clothing could receive a second-degree burn from an arc flash.
- Limited approach boundary
- The shock protection boundary for a 480-volt system is 10 feet; only qualified persons may cross it with proper PPE.
- Restricted approach boundary
- The shock protection boundary for a 480-volt system is 1 foot; only qualified persons with proper PPE and a work permit may cross it.
- Lockout/tagout
- A procedure to de-energize equipment, apply locks and tags, and verify the absence of voltage before work begins.
- Parallel conductor requirements
- Parallel conductors must be the same length, material, circular mil area, insulation type, and terminated in the same manner; minimum size is 1/0 AWG.
- Conduit expansion fitting
- A fitting required where raceways are subject to significant temperature changes, such as exposed rooftop runs, to accommodate expansion and contraction.
- Feeder conductor sizing
- Feeder ampacity must be at least 125% of the continuous load plus 100% of the noncontinuous load before adjustment and correction factors.
- Optional dwelling calculation
- Under NEC 220.82, total general load is subject to a 100% demand factor for the first 10 kVA and 40% for the remainder.
- Class II location
- A location where combustible dust is or may be present in quantities sufficient to produce an explosion or ignitable mixture.
- Health care essential system
- A system required in hospitals and other health care facilities that must be separated into critical, life safety, and equipment branches.