Exam Cheat Sheet · Quick Reference
Idaho Limited Electrical Elevator Installer
Idaho · PSI Services Contractor
Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
60
Passing score
70%
Exam time
180 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Idaho State Portion 60 questions
2017 National Electrical Code, NFPA – Introduction
4 Q · 7%
Purpose and scope of the NEC (practical safeguarding vs. design specification)Installations covered and not covered under NEC scope (90.2)Code arrangement and chapter hierarchy (Chapters 1–9 and informative annexes)Authority having jurisdiction (AHJ) enforcement powers and special permissionMandatory vs. permissive rules and explanatory material (shall/shall not vs. shall be permitted)Equipment examination, listing, and approval for safety (90.7)Wiring planning for future expansion and circuit limitations in enclosures (90.8)Units of measurement: SI and inch-pound dual system and compliance (90.9)
2017 National Electrical Code, NFPA – Chapter 1
10 Q · 17%
Key NEC Article 100 definitions (approved, listed, labeled, identified, AHJ)Branch circuit types and definitions (general-purpose, individual, multiwire, appliance)Grounding and bonding terminology (grounded conductor, EGC, grounding electrode, bonding jumper types)Equipment approval, examination criteria, and listing requirements (Article 110.3)Working space and clearance requirements for electrical equipment (110.26 dimensions and conditions)Guarding of live parts and enclosure type selection (110.27, Table 110.28)Electrical connections, conductor materials, temperature limitations, and torque requirements (110.14)Arc-flash hazard warning markings and available fault current field marking requirements (110.16, 110.24)Article 100 - DefinitionsArticle 110 - Requirements for Electrical Installations
2017 National Electrical Code, NFPA – Chapter 2
10 Q · 17%
Grounding and bonding requirements for grounded and ungrounded AC systems (Article 250)Grounding electrode system types, installation, and sizing (Article 250, Part III)Equipment grounding conductor types, sizing, and identification (Article 250, Parts VI–VII)Bonding of services, piping systems, and structural metal (Article 250, Part V)Branch-circuit ratings, conductor ampacity, and overcurrent protection (Article 210)GFCI and AFCI protection requirements for branch circuits (Article 210)Branch-circuit, feeder, and service load calculations including demand factors (Article 220)Feeder conductor sizing, overcurrent protection, and identification (Article 215)Article 250 - Grounding and Bonding
2017 National Electrical Code, NFPA – Chapter 3
10 Q · 17%
Conductor ampacity tables and adjustment factors (Article 310)Conductor insulation types, temperature ratings, and permitted uses by locationWiring methods installation requirements: securing, supporting, and bending (RMC, EMT, FMC, LFMC, LFNC, PVC)Underground installation requirements and minimum cover depths (Table 300.5)Box and conduit body fill calculations and sizing (Article 314)Cable tray systems: uses permitted, fill requirements, and ampacity (Article 392)Conductors in parallel: minimum size and installation requirementsCabinets, cutout boxes, and enclosures: wire-bending space and conductor deflection (Article 312)Article 310 - Conductors for General Wiring
2017 National Electrical Code, NFPA – Chapter 4
10 Q · 17%
Motor branch-circuit conductor sizing and ampacity requirementsMotor overload protection devices and trip current ratingsMotor branch-circuit short-circuit and ground-fault protective device ratings and settingsMotor controller ratings, types, and marking requirementsMotor disconnecting means types, location, and ampere rating requirementsMotor control circuit overcurrent protection and electrical arrangementTransformer overcurrent protection and installation requirements by typeSwitchboard, switchgear, and panelboard overcurrent protection, grounding, and markingArticle 430 - Motors, Motor Circuits, and Controllers
2017 National Electrical Code, NFPA – Chapter 6
15 Q · 25%
Disconnecting means requirements for elevators, escalators, and platform liftsWiring methods in hoistways, machine rooms, and on elevator carsConductor insulation types and minimum sizes for traveling cables and hoistway wiringGrounding and bonding requirements for electric elevators and escalatorsGFCI protection requirements for receptacles in pits, hoistways, and machine roomsVoltage limitations for power, lighting, and heating circuitsOvercurrent protection for elevator motors and feeder selective coordinationEmergency and standby power system connections for elevators
2017 National Electrical Code, NFPA Calculations
1 Q · 2%
Motor branch-circuit conductor ampacity calculations (Article 430, 125% rule)Motor branch-circuit short-circuit and ground-fault protective device sizing using Table 430.52Full-load current determination from NEC Tables 430.247–430.250Feeder conductor ampacity for multiple motors (Article 430.24 summation method)Elevator feeder and branch-circuit conductor sizing using Article 620.13 and Table 430.22(E)Feeder demand factors for elevator installations (Table 620.14)Motor overload protection sizing percentages (Article 430.32)Conduit fill calculations using Chapter 9 Tables 1, 4, and 5Article 430 - Motors, Motor Circuits, and Controllers
Key Distinctions
Motor-circuit switchvsGeneral-use switch / isolating switch
A motor-circuit switch is rated in horsepower and can interrupt the maximum operating overload current of a motor of the same horsepower rating at rated voltage, while a general-use switch is rated in amperes and an isolating switch has no interrupting rating.
NEC 2017 Article 100 (Definition of Switch, Motor-Circuit)Main bonding jumpervsSystem bonding jumper
The main bonding jumper connects the grounded circuit conductor to the equipment grounding conductor at the service, while the system bonding jumper makes that same type of connection at a separately derived system.
NEC 2017 Article 100 (Definition: Bonding Jumper, Main)Receptacles in elevator pits, hoistways, and escalator/moving walk wellwaysvsReceptacles in machine rooms, control rooms, and control spaces
Per 620.85, 125-volt, single-phase, 15- and 20-ampere receptacles in pits, hoistways, and wellways must themselves be of the GFCI type, whereas those in machine rooms, control rooms, and control spaces need only have GFCI protection for personnel, which may be provided upstream.
NEC 2017 Section 620.85Wye-start, delta-run motor conductors (430.22(C))vsPart-winding connected motor conductors (430.22(D))
Conductors between controller and motor must be not less than 72 percent of motor full-load current for wye-start, delta-run motors, but not less than 62.5 percent for part-winding connected motors; 125 percent applies to the line-side conductors in both cases.
NEC 2017 Section 430.22(C)Overload device at 125% (430.32(A)(1))vsOverload device at 115% (430.32(A)(1))
A separate overload device for a continuous-duty motor is limited to a maximum of 125 percent of nameplate full-load current when the motor is marked with a service factor of 1.15 or greater or a temperature rise of 40°C or less, and a maximum of 115 percent for all other motors (two separate maximums, not a range).
NEC 2017 Section 430.32(A)(1), 430.32(C)Motor disconnecting means rating (430.110(A)) — 115%vsMotor branch-circuit conductor sizing (430.22) — 125%
The disconnecting means for motor circuits rated 1000 volts or less must be rated not less than 115 percent of motor full-load current (except a listed unfused motor-circuit switch rated in horsepower), while branch-circuit conductors for a single continuous-duty motor must be not less than 125 percent of full-load current.
NEC 2017 Section 430.110(A)240.4(B) next higher standard OCPD ratingvs240.4(C) overcurrent device rated over 800 amperes
The next higher standard overcurrent device rating above conductor ampacity is permitted only where the selected rating does not exceed 800 amperes; where the device is rated over 800 amperes, the conductor ampacity must be equal to or greater than the device rating.
NEC 2017 Section 240.4(B)Hard conversion (default in 90.9(C))vsSoft conversion (permitted exceptions)
The Code requires SI conversion to be based on hard conversion, but soft conversion is permitted for the listed cases of trade size designators for products, extracted material, industry practice, and safety.
NEC 2017 Section 90.9(C)(1)Insulated conductorvsCovered conductor
An insulated conductor is encased within material of composition and thickness recognized by the Code as electrical insulation, while a covered conductor is encased in material not recognized as electrical insulation.
NEC 2017 Article 100 (Conductor, Insulated)Multifamily dwellingvsTwo-family dwelling
A multifamily dwelling is a building containing three or more dwelling units; a building with exactly two units is a two-family dwelling.
NEC 2017 Article 100 (Definition of Dwelling, Multifamily)Tag marking (310.120(B)(3))vsSurface marking (310.120(B)(1))
Type MI cable, switchboard wires, metal-covered single-conductor cables, and Type AC cable are marked by a printed tag on the coil, reel, or carton, while nonmetallic-sheathed, service-entrance, and underground feeder cables are durably surface marked.
NEC 2017 Section 310.120(B)(3)Instantaneous trip breaker — Design B energy-efficient squirrel cage motorvsInstantaneous trip breaker — other AC polyphase motors
Table 430.52 permits a maximum of 1100 percent of full-load current for Design B energy-efficient squirrel cage motors versus a maximum of 800 percent for other AC polyphase motor types.
NEC 2017 Table 430.52Opening above a lay-in ceiling (110.26(A)(4)(a))vsAccessible opening in a crawl space
Equipment installed above a lay-in ceiling requires an access opening not smaller than 22 in. × 22 in., while the 22 in. × 30 in. dimension applies to an accessible opening in a crawl space.
NEC 2017 Section 110.26(A)(4)(a)Key Terms
Ampacity NEC 2017
The maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Continuous Load NEC 2017 Article 100
A load where the maximum current is expected to continue for 3 hours or more.
Authority Having Jurisdiction (AHJ) NEC 2017 Article 100 (Definitions)
An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure; per 90.4 the AHJ makes interpretations of the rules, decides on approval of equipment and materials, and grants special permission.
Motor-Circuit Switch NEC 2017 Article 100 (Definition of Switch, Motor-Circuit)
A switch rated in horsepower that is capable of interrupting the maximum operating overload current of a motor of the same horsepower rating at the rated voltage.
Bonding Conductor or Jumper NEC 2017 Article 100 (Definition: Bonding Conductor or Jumper)
A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.
Main Bonding Jumper NEC 2017 Article 100 (Definition: Bonding Jumper, Main)
The connection between the grounded circuit conductor and the equipment grounding conductor at the service.
System Bonding Jumper NEC 2017 Article 100 (Definition: Bonding Jumper, System)
The connection between the grounded circuit conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system.
Effective Ground-Fault Current Path NEC 2017 Section 250.4(A)(5)
A low-impedance circuit capable of safely carrying the maximum ground-fault current to facilitate operation of the overcurrent device; per 250.4(A)(5) the earth shall not be considered as an effective ground-fault current path.
Duty, Varying NEC 2017 Article 100 (Definition of Duty, Varying)
Operation at loads, and for intervals of time, both of which may be subject to wide variation (periodic duty is intermittent operation with regularly recurrent load conditions; short-time duty is a substantially constant load for a short, definite, specified time).
Simple Apparatus NEC 2017 Article 100 (Definition of Simple Apparatus)
For hazardous (classified) locations, an electrical component or combination of components of simple construction with well-defined electrical parameters that, as a source of generated energy, does not exceed 1.5 volts, 100 mA, and 25 mW (or a passive component dissipating not more than 1.3 watts).
Hybrid System NEC 2017 Article 100 (Definition of Hybrid System)
A system comprised of multiple power sources such as photovoltaic, wind, microhydro generators, and engine-driven generators; energy storage systems and energy regenerated by an overhauling (descending) elevator are not power sources for this definition.
Supplementary Overcurrent Protection (240.10) NEC 2017 Section 240.10
Protection that shall not be used as a substitute for required branch-circuit overcurrent devices or in place of required branch-circuit protection.
Adjustable-Trip Circuit Breaker Rating (240.6(B)) NEC 2017
Where the breaker has external means for adjusting the long-time pickup setting and does not meet 240.6(C) for restricted access, its rating is the maximum setting possible.
Plug Fuse Identification (240.50(C)) NEC 2017 Section 240.50(C)
Plug fuses of 15-ampere and lower rating must be identified by a hexagonal configuration of the window, cap, or other prominent part to distinguish them from higher ampere ratings.
Ground-Fault Protection of Equipment (240.13) NEC 2017 Section 240.13
Required on solidly grounded wye systems of more than 150 volts to ground but not exceeding 1000 volts phase-to-phase for each individual device used as a building or structure main disconnecting means rated 1000 amperes or more.
Elevator Controller Multiple-Source Warning Sign (620.52(B)) NEC 2017 Section 620.52(B)
Where parts of a controller remain energized from another source, a clearly legible sign on or next to the disconnecting means must read "WARNING — PARTS OF THE CONTROLLER ARE NOT DE-ENERGIZED BY THIS SWITCH."
Formulas to Know
Minimum feeder conductor ampacity for continuous plus noncontinuous load (215.2(A)(1)(a))
Feeder conductor ampacity ≥ noncontinuous load + (1.25 × continuous load); example: 120 A + (80 A × 1.25) = 220 AMinimum feeder overcurrent device rating, assembly not listed for 100% rating (215.3)
Rating ≥ noncontinuous load + (1.25 × continuous load), then go to next higher standard rating from Table 240.6(A); example: (120 × 1.25) + 60 = 210 A → 225 AMotor branch-circuit conductor ampacity multipliers (430.22)
Single continuous-duty motor (line side of controller): ≥ 125% of motor FLC; wye-start, delta-run controller-to-motor conductors: ≥ 72% of FLC (58% × 1.25); part-winding controller-to-motor conductors: ≥ 62.5% of FLC (50% × 1.25)Feeder ampacity for several continuous-duty motors (430.24)
Ampacity ≥ (1.25 × FLC of highest rated motor) + sum of FLCs of all other motors; example: (1.25 × 28) + 17 + 10 = 62 AInverse time circuit breaker for a single motor (Table 430.52(C)(1) and Exception No. 2)
Table maximum = 250% of motor FLC (50 A × 2.5 = 125 A); if the motor will not start, the rating may be increased but shall not exceed 400% of FLC for motors of 100 A or less (50 A × 4 = 200 A; 60 A × 4 = 240 A) and 300% for motors above 100 AMaximum separate overload device rating for a continuous-duty motor (430.32(A)(1))
Service factor 1.15 or greater, or temperature rise 40°C or less: ≤ 125% of nameplate FLC (30 A × 1.25 = 37.5 A); all other motors: ≤ 115% of nameplate FLC (30 A × 1.15 = 34.5 A); only if insufficient to start the motor does 430.32(C) permit up to 130% or 140%Conduit fill using Chapter 9 Tables 1, 4, and 5
Total conductor area = sum of (quantity × Table 5 area each), including the equipment grounding conductor at actual area (Note 3); over 2 conductors use the 40% column, exactly 2 conductors use the 31% column; maximum number = (allowed area ÷ area per conductor), and per Note 7 drop the fraction when it is below 0.8 (e.g., 0.814 ÷ 0.0507 = 16.06 → 16; 2.343 ÷ 0.0211 = 111.04 → 111)Additional conductors permitted in a box (314.16(B))
Spare volume = box volume − volume used; additional 14 AWG conductors = spare volume ÷ 2.00 cu in (whole conductors only); example: 25.5 − 24.00 = 1.50 ÷ 2.00 = 0.75 → 0 additionalDwelling-unit load before demand factors (Article 220)
General lighting (area sq ft × 3 VA/sq ft) + 1,500 VA per small-appliance branch circuit + 1,500 VA per laundry circuit; examples: 1,800 sq ft home = 5,400 + (3 × 1,500) + (2 × 1,500) = 12,900 VA; each 1,200 sq ft unit = 3,600 + 3,000 + 1,500 = 8,100 VA, × 4 units = 32,400 VARetail store general lighting plus receptacle load before demand factors (NEC 2020/2023/2026)
(area sq ft × 1.9 VA/sq ft) + (180 VA × number of receptacle outlets on one yoke); example: (3,500 × 1.9 = 6,650) + (20 × 180 = 3,600) = 10,250 VA; note 3 VA/sq ft was the NEC 2017 store unit load