FREE NEC Code Basic Questions and Answers
Equipment with cords and plugs cannot be rated at more than ______ of the branch circuit rating if it is not fixed in place.
The National Electrical Code (NEC) addresses the rating of cord and plug equipment not fastened in place in Article 400.7(A)(3). It states that flexible cord and plug-connected equipment (such as appliances or portable tools) must not be rated more than 80% of the branch circuit rating.
The overload device shall not be larger than ______ of the motor nameplate current ratings for motors with an indicated service factor (SF) of 1.15 or higher on the nameplate:
According to the National Electrical Code (NEC) and general motor design principles, motors with a marked service factor (SF) of 1.15 or higher on the nameplate have increased overload capacity. When determining the size of the overload protection device for such motors, it should not exceed 125% of the motor's nameplate current rating.
For connecting equipment or taps to luminaires, FMC Trade size 3/8 can be used in lengths no longer than :
According to the NEC, FMC and LFMC trade size 3/8 inch can be used in lengths not exceeding 6 feet
Every box, cabinet, or temperature fitting, such as a conduit body, must have electrical nonmetallic tubing secured within:
In general, the NEC requires that electrical nonmetallic tubing (ENT) must be securely fastened or supported within certain distances from boxes, cabinets, fittings, or other termination points to ensure the stability and integrity of the wiring system
The cold water input must be _____ away from the underside of any mobile or constructed house pipe heat tape receptacle outlets:
The general guideline is to install pipe heat tape receptacle outlets on the underside of the mobile or manufactured home and within 2 feet of the cold water inlet. Placing the receptacle outlets on the underside helps protect them from weather exposure, and the proximity to the cold water inlet ensures effective heat application to prevent freezing in the most vulnerable section of the water supply system.
Information technology equipment branch circuit conductors must have an ampacity that is at least ____ of the total load connected:
According to the National Electrical Code (NEC) in the United States, branch circuit conductors that supply power to information technology equipment must have an ampacity not less than 125% of the total load connected to the branch circuit.
Motor feeder tap conductors that are not more than ___ length must have an ampacity that is at least ten times the feeder protection device's rating.
The NEC allows for motor feeder tap conductors, which are conductors that supply power to motors, to be up to 10 feet long without requiring their own separate overcurrent protection. In this scenario, the tap conductors must meet certain conditions:
A device box or plaster ring fastened to a device box can hold a vertically mounted luminaire weighing no more than :
The National Electrical Code (NEC) permits the vertical mounting of luminaires weighing no more than 6 lb to be supported by a device box or plaster ring secured to a device box under certain conditions.
The specific requirements are outlined in NEC 314.27(C), which allows the use of a device box or plaster ring to support a lighting fixture weighing up to 6 lb.
Ground fault protection for the overcurrent device for the primary feeder wires in marinas must not be greater than:
In some regions or specific applications, there may be requirements for ground fault protection not exceeding 100 mA (milliamperes) for the main marina feeder conductors. This means that the overcurrent device used for the main feeder conductors should have ground fault protection that can detect and interrupt current flow if a fault to ground occurs, and the protection must not exceed 100 mA.
For a mast termination above the floor, RMC need not be firmly attached within __ of the service head:
RMC is a type of metal conduit that provides mechanical protection for electrical conductors. The installation requirements for RMC depend on the specific application and the type of wiring method used.
The cord must contain a copper equipment grounding conductor that is not less than ____ and must end at a grounding type attachment plug for fixed or stationary equipment other than an underwater luminaire for permanently installed pools:
The equipment grounding conductor should not be smaller than 12 AWG (American Wire Gauge). Larger conductors (smaller gauge numbers) have a higher current-carrying capacity, which is beneficial for effective grounding.
Separately generated systems with a rating of __ or less are exempt from grounding requirements:
In some electrical codes, separately derived systems rated 1 kVA or less may be exempt from the requirement to have a separate grounding electrode. However, even if a separately derived system is exempt from having a grounding electrode, it might still require a bond to the main grounding system or be required to meet other specific grounding or bonding requirements.
For the purpose of sizing branch circuits, an electric heater with a capacity of __ gallons or less is regarded as a continuous load:
According to the National Electrical Code (NEC) in the United States, electric space heating equipment that has a capacity of 120 volts or less and exceeds 48 amperes must be considered a continuous load for branch circuit sizing purposes. This means that the branch circuit supplying power to the heater should be designed to handle the continuous current without being overloaded.
The permissible ampacity for copper conductor of 10 AWG at 60° C is .
For a 10 AWG copper conductor with insulation rated at 60°C (140°F), the allowable ampacity is typically 30 amperes. This means that the conductor can safely carry a maximum continuous current of up to 30 amperes when operating under normal conditions.
The maximum overcurrent protection for a transformer with primary windings not exceeding 600 V and primary current ratings under 2 A is as:
For transformers with a primary current rating of less than 2 A, the primary overcurrent protection can be sized up to 300% of the rated primary current when the transformer is supplied by a branch circuit with appropriate overcurrent protection.
With more than three levels. Behind floors, walls, or ceilings with a ____ minute finish rating, ENT must be hidden:
One critical consideration when concealing ENT is to ensure that the construction materials used for the floors, walls, or ceilings have an appropriate fire rating. The fire rating is a measure of how long the material can withstand exposure to fire without losing its integrity. The fire rating is typically expressed in minutes (e.g., 15-minute fire rating).