Article 100 & 110
This term defines a device or conductor connected to establish electrical continuity and conductivity.
What is Bonded (or Bonding)?
In dwelling units, all 125-volt through 250-volt receptacles installed within this many feet of the inside edge of a sink bowl require GFCI protection.
What is 6 feet?
DAILY DOUBLE:This is the minimum number of service disconnects allowed for a single building before requiring a main split, commonly known as the "blank disconnect rule" (which was heavily restricted in 2020/2023 to require separate enclosures).
What is six?
This common residential cable type consists of a moisture-resistant, flame-retardant nonmetallic sheath enclosing two or more insulated conductors.
What is Type NM cable (Romex)?
Article 680 requires that all metallic parts of a swimming pool structure within this many feet of the inside walls of the pool must be bonded together.
What is 5 feet?
According to Article 110, the minimum headroom working space about service equipment, switchboards, or motor control centers must be this many feet.
What is 6½ feet (or 2.0 meters)?
This is a type of device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when this type of fault is detected.
What is an AFCI (Arc-Fault Circuit Interrupter)?
Overhead service conductors must maintain a minimum vertical clearance of this many feet over residential driveways.
What is 12 feet?
When counting conductors for box fill calculation, all equipment grounding conductors in a box count as a combined volume based on the largest EGC, counting as how many allowances?
What is a single volume allowance? (Note: The 2020/2023 NEC adds a 1/4 volume count for each additional EGC past 4, but the initial baseline is a single allowance group).
Article 625 mandates that Electric Vehicle Supply Equipment (EVSE) output cable must have this safety feature to shut off power if the cord is severed or strained.
What is an automatic disconnect (or personnel protection system/GFCI)?
This type of location is protected from weather and not subject to saturation with water or other liquids, but is subject to moderate degrees of moisture.
What is a Damp Location (or Location, Damp)?
The NEC recommends that the total voltage drop on a branch circuit plus the feeder should not exceed this total percentage for maximum efficiency.
What is 5 percent? (3% for branch circuit / 3% for feeder individually).
When calculating dwelling unit loads, the general lighting load is calculated using a unit load of this many volt-amperes (VA) per square foot (adjusted in recent NEC editions).
What is 3 VA? (Note: The 2023 NEC shifted residential lighting tables to Article 220).
Rigid Polyvinyl Chloride Conduit is commonly abbreviated as this wiring method type.
What is Type PVC?
Generators, solar inverters, and storage batteries that can operate in parallel with a primary source of electricity to feed a structure fall under Article 705, known by this term.
What is an Interconnected Electric Power Production Source?
Section 110.16 requires this type of label on electrical equipment to warn qualified persons of potential electric shock and flash hazards.
What is an Arc-Flash Warning label?
Dwelling unit kitchen countertops require a minimum of this many small-appliance branch circuits.
What is two?
For a standard single-family dwelling, the 2023 NEC mandates a minimum service rating of this many amperes.
What is 100 amperes?
When more than this many current-carrying conductors are bundled together in a raceway or cable for more than 24 inches, their ampacity must be derated.
What is three?
Emergency systems covered by Article 700 must be able to automatically supply backup power to critical loads within this many seconds of losing normal power.
What is 10 seconds?
This key term refers to an area intended to provide access, operation, and maintenance around electrical equipment, typically requiring a depth of 3 to 4 feet depending on voltage to ground.
What is Working Space?
Receptacles installed outdoors (in wet locations) for dwelling units must be provided with this type of enclosure, even when the attachment plug cap is inserted (frequently called an "In-Use" cover).
What is a weatherproof enclosure?
Under Article 230, this device must be installed outdoors for one-family and two-family dwellings to allow first responders to cut power quickly.
What is an Emergency Disconnect?
Type MC cable must be supported at intervals not exceeding this many feet, as well as within 12 inches of every box or termination point.
What is 6 feet?
According to Article 430, a motor disconnecting means must be located within sight from the motor location and driven machinery, which means a distance of no more than this many feet.
What is 50 feet?
Conductors must have a termination temperature rating that matches the temperature rating of this, typically limited to 60°C or 75°C for circuits under 100 amperes.
What is the equipment terminal (or lug)?
The 2023 NEC expanded GFCI requirements to include specific multi-phase outlets, now mandating protection for all kitchen receptacles up to this specific amperage rating.
What is 50 amperes?
When applying demand factors for household electric clothes dryers, you can use 100% demand for up to 4 dryers, but the minimum VA allocated per dryer must be at least this value.
What is 5,000 volt-amperes (VA)?
This standard table in Chapter 3 is used to determine the allowable ampacities of insulated conductors rated up to 2000 volts.
What is Table 310.16?
For Solar Photovoltaic (PV) systems, Article 690 requires a controlled strategy to reduce shock hazards for emergency responders, known by this two-word term.
What is Rapid Shutdown?
NEC 110.26(C)(2) requires a large equipment room (1200A or more) to have two entrance/egress doors unless the path of travel to the exit is this.
What is unobstructed? (Or: double the required working space depth).
For a continuous load, the branch-circuit conductors and overcurrent protective devices must be sized at not less than this percentage of the continuous load.
What is 125 percent?
The optional calculation method for a dwelling unit allows a demand factor of this percentage to be applied to the nameplate rating of an electric space heating load versus an air conditioning load (whichever is larger).
What is 100 percent?
DAILY DOUBLE: To prevent damage to wire insulation during a pull, the total number of bends (in degrees) between pull points in a run of conduit cannot exceed this many degrees.
What is 360 degrees?
Article 500 classifies a location where flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures as this specific class.
What is Class I (specifically Class I, Division 1 or 2)?
Newly emphasized in recent editions, this term means "admitted close enough to look at, repair, or operate without requiring the removal of panels or climbing over obstacles."
What is Readily Accessible?
No receptacle can be installed within a zone measured 3 feet horizontally and 8 feet vertically from the top of this bathroom fixture.
What is a bathtub or shower stall threshold?
Service-entrance conductors passing vertically through a roof must terminate at a service head that is located above the point of attachment of the service-drop conductors, unless this exception applies.
What is where it is impracticable to do so? (Within 24 inches of attachment).
This type of raceway, abbreviated as LFMC, requires a liquid tight outer jacket over a flexible metal core and has specific grounding restrictions over 6 feet.
What is Liquid-tight Flexible Metal Conduit?
Added and heavily detailed in recent codes to accommodate green energy, this system, abbreviated as ESS, utilizes batteries or flywheels to store and discharge energy.
What is an Energy Storage System?