gh-ec-electrical-wiring-domestic flashcards

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

Ohm's Law

In a DC or purely resistive circuit, voltage equals current times resistance (E = I × R). Rearranged, current equals voltage divided by resistance, and resistance equals voltage divided by current.

Continuous load definition

A load expected to operate at maximum current for three hours or more. Conductors and overcurrent devices serving it are generally sized at 125% of the continuous load plus 100% of noncontinuous load.

Box fill counting

Count 14 AWG as 2.0 cubic inches, 12 AWG as 2.25, and 10 AWG as 2.5. Add one conductor volume for each device yoke, each clamp, and the grounding conductors.

NM cable support intervals

Nonmetallic-sheathed cable must be secured within 12 inches of each box and at intervals not exceeding 4.5 feet. Bored holes require support within 12 inches of the hole.

Small-appliance branch circuits

Dwellings require at least two 20-ampere circuits for kitchen and dining receptacles, with no other outlets connected. Each circuit counts 1,500 volt-amperes in the load calculation.

General lighting load dwelling

Dwelling general lighting is calculated at 3 volt-amperes per square foot. Demand factors in Table 220.42 then apply, with the first 3,000 volt-amperes at 100 percent.

Grounding electrode conductor sizing

Sized from Table 250.66 based on the largest service conductor. A concrete-encased electrode or ground ring needs only a 4 AWG copper conductor regardless of service size.

Single electrode rule

A single rod, pipe, or plate electrode must have 25 ohms or less resistance to earth, or it must be supplemented by one additional electrode of any permitted type.

Receptacle spacing rule

In habitable rooms, wall-space receptacles must be installed so no point along the floor line is more than 6 feet from a receptacle, and any wall space 2 feet or wider needs one.

Ungrounded receptacle replacement

A grounding-type receptacle may replace an ungrounded one only with GFCI protection and a marking reading "No Equipment Ground." The equipment grounding conductor is not connected.

Bathroom circuit requirement

At least one 20-ampere branch circuit must supply only bathroom receptacles. All bathroom receptacles require GFCI protection and none may be inside the shower or tub space.

Kitchen countertop receptacle rule

Countertop receptacles must be GFCI-protected and installed so no point along the countertop is more than 24 inches from a receptacle. Islands and peninsulas also require one.

Motor conductor sizing

Motor branch-circuit conductors are sized at 125% of the full-load current from Article 430 tables, not the nameplate current, unless a specific listed motor exception applies.

HVAC nameplate sizing

A central air conditioner or heat pump lists minimum circuit ampacity and maximum overcurrent protection. Conductors must be at least the MCA and the breaker must not exceed the MOCP.

Class 2 separation rule

Class 2 cables must be separated from power conductors by at least 2 inches or a permanent barrier, and must cross power conductors at right angles where practical.

Communications primary protector

Communications cables entering a building require a listed primary protector at the point of entry, bonded to the building grounding electrode system with a minimum 6 AWG copper conductor.

Working clearance 120 volts

For equipment operating at 0 to 150 volts to ground, the minimum working space depth is 3 feet, with 30 inches of width and 6.5 feet of headroom.

GFCI tester result

A GFCI tester simulates a ground fault and should trip the device. If it does not trip, the device or its wiring is defective and must be corrected before final inspection.

Georgia license classes

Georgia issues electrical contractor licenses in classes, including Class I for unlimited work and Class II limited to smaller services and specified voltage limits. The class defines the scope.

Qualifying agent role

A licensed business must designate a qualifying agent who holds the license, is an owner, officer, or employee, and is responsible for the electrical work the business performs.

Series circuit characteristics

Current is the same through every component, resistances add directly, and voltage divides across the loads in proportion to their resistance.

Conduit fill percentages

For raceway fill, one conductor may occupy up to 53 percent of the interior cross-section, two conductors 31 percent, and three or more conductors 40 percent.

Voltage drop formula

For a single-phase two-wire circuit, voltage drop equals 2 times K times current times length divided by circular mils, where K is about 12.9 for copper.

Main bonding jumper location

The main bonding jumper connects the grounded service conductor to the service equipment enclosure and grounding bus. It is installed only at the service, never at subpanels.

Three-way switch travelers

A three-way switch has two traveler terminals and one common terminal. The common connects to the ungrounded supply or the load, and travelers run between the two switches.

Garage receptacle requirement

A dwelling garage requires at least one 20-ampere branch circuit for receptacles, GFCI-protected, plus a lighting outlet controlled by a switch at the vehicle entrance.

Motor overload protection setting

Motor overload relays are set at 115 percent of nameplate current for a motor with a 1.15 service factor, and 125 percent for a motor with a 1.0 service factor.

Fire alarm circuit classes

Class A initiating circuits survive a single open or ground fault and continue to operate, while Class B circuits do not survive a single open and signal a trouble condition.

Lockout tagout procedure

De-energize the circuit, lock the disconnect, and verify with a tester rated for the voltage. Treat all conductors as energized until testing proves otherwise.

Georgia continuing education

Georgia electrical contractors must complete continuing education hours each renewal cycle, commonly 8 hours per two-year cycle, including code-update content.

Ampacity adjustment factors

Conductor ampacity is corrected for ambient temperature and adjusted when more than three current-carrying conductors share a raceway or cable, using the tables in 310.15.

Equipment grounding conductor sizing

The equipment grounding conductor is sized from Table 250.122 based on the rating of the overcurrent device protecting the circuit, not on the conductor ampacity.