MI Journeyman Electrician flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Working space depth, 0-150 volts

For equipment operating at 0 to 150 volts to ground, the clear working space in front of the equipment must be at least 3 ft deep, 30 in. wide, and 6 ft 6 in. high.

Informational Note enforceability

Informational Notes in the National Electrical Code are explanatory only. They are not mandatory rules, are not enforceable as code requirements, and are not part of the mandatory text.

AHJ authority to interpret code

Section 90.4 gives the authority having jurisdiction responsibility for interpreting the code, approving listed materials and methods, and granting written approval of alternate installations that provide equivalent safety.

Michigan Electrical Code adoption

Michigan adopts the National Electrical Code by reference with state amendments as the Michigan Electrical Code; the adopted edition and amendments control plan review and field inspection.

60 degrees C termination limit

Unless equipment is listed and marked otherwise, conductor ampacity at terminations for circuits rated 100 amperes or less is limited to the 60 degrees C column of the ampacity tables.

Table 310.16 base conditions

Ampacities in Table 310.16 assume an ambient temperature of 30 degrees C and no more than three current-carrying conductors; higher temperatures or more conductors require correction or adjustment.

Electrical Administrative Act licensing

Michigan's Electrical Administrative Act, Public Act 217 of 1956, governs licensing of electrical contractors, master and journeyman electricians, and registered electrical apprentices throughout the state.

Minimum service rating, dwelling unit

NEC 230.79(C) requires the service disconnecting means for a one-family dwelling to have a rating of not less than 100 amperes.

Small-appliance branch circuits

Dwelling unit kitchens, dining areas, and similar spaces require at least two 20-ampere small-appliance branch circuits, and those circuits may not supply outlets outside those areas.

Receptacle spacing 6-foot rule

In dwelling units, receptacle outlets must be installed so that no point along the floor line of any wall space is more than 6 feet from a receptacle outlet.

Countertop receptacle 24-inch rule

Kitchen and similar countertop receptacles must be installed so that no point along the counter wall line is more than 24 inches from a receptacle outlet.

Voltage drop 3 and 5 percent

NEC informational notes recommend limiting voltage drop to 3 percent on a branch circuit and 5 percent total for the feeder plus branch circuit combined.

Dwelling lighting load 3 VA

The general lighting load for a dwelling unit is calculated at 3 volt-amperes per square foot of floor area under NEC 220.12.

Box fill, 12 AWG

Table 314.16(B) assigns 2.25 cubic inches to each 12 AWG conductor; all equipment grounding conductors count together as one, and each device yoke counts as one conductor.

Raceway fill percentages

Chapter 9 Table 1 permits a raceway to be filled to 40 percent of its interior cross-sectional area for three or more conductors, 31 percent for two, and 53 percent for one.

EMT support intervals

Electrical metallic tubing must be fastened within 3 feet of each box or termination and supported at intervals not exceeding 10 feet along the run.

NM cable support intervals

Nonmetallic-sheathed cable must be secured within 12 inches of each box and supported at intervals not exceeding 4.5 feet along its run.

Nail plate protection

Where cables or raceways pass through bored holes in framing, they must be at least 1-1/4 inches from the nearest edge, or protected by a listed steel plate.

Straight pull box length

For a straight pull, the minimum length of a pull box is eight times the trade size of the largest raceway entering the box.

Equipment grounding conductor identification

Equipment grounding conductors must be bare, green, or green with one or more yellow stripes; white and gray identification is not permitted for these conductors.

Motor conductor 125 percent

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the motor full-load current taken from the applicable Article 430 tables.

Switch height above floor

Switches and circuit breakers used as switches must not be installed more than 6 feet 7 inches above the floor or working platform.

Air-conditioning nameplate sizing

Air-conditioning conductors, disconnects, and overcurrent devices are sized from the equipment nameplate minimum circuit ampacity and the nameplate maximum overcurrent protective device rating.

Motor inverse-time breaker 250 percent

Table 430.52 permits an inverse-time circuit breaker protecting a motor branch circuit against short circuits and ground faults at up to 250 percent of motor full-load current.

Tamper-resistant receptacle requirements

Listed tamper-resistant receptacles are required in dwelling units and guest rooms, and in specified child-care, educational, and similar occupancies, under NEC 406.12.

Transformer primary-only protection

For transformers rated 1000 volts or less with primary-only overcurrent protection, the device must be sized at no more than 125 percent of the primary current.

Ground rod 25 ohms

A single ground rod or pipe electrode must have a resistance to earth of 25 ohms or less, or a supplemental electrode must be installed to supplement it.

EGC proportional increase

Where phase conductors are increased in size above the code minimum, the equipment grounding conductor must also be increased proportionally, based on circular mil area.

Small conductor overcurrent limits

NEC 240.4(D) limits overcurrent protection for small conductors: 14 AWG copper to 15 amperes, 12 AWG copper to 20 amperes, and 10 AWG copper to 30 amperes.

Standard overcurrent device ratings

NEC 240.6 lists standard ampere ratings for fuses and circuit breakers, including 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, and 600 amperes.

Class I Division 1 location

A Class I, Division 1 location is one where ignitable concentrations of flammable gases, vapors, or liquids can exist under normal operating conditions or frequently during repair and maintenance.

Pool equipotential bonding

NEC 680.26 requires an equipotential bonding grid for pools, connecting metal parts of the pool structure, fittings, and adjacent perimeter surfaces within 3 feet of the pool.