Electrical, Lighting & Acoustics Flashcards
Electrical Systems: Outlets
Both NEC and the 2018 International Residential Code
have the most extensive requirements for dwelling
units, such as:
One outlet every 12 feet maximum along
unbroken walls in a “habitable” space (this
includes around corners)
A maximum of 6 feet from any obstruction or
“break” in a wall such as a door
No outlet required on an “unbroken” wall (as in
between two doors) shorter than 2 feet
At least one wall switched electrical outlet per
“habitable” room.
Wall outlet calculations cannot include floor
outlets more than 18 inches from a wall.
One outlet every 4 feet of countertops in kitchens
GFCI-protected outlets required in bathrooms
and kitchens
Electrical Systems: Outlets
What is represented by the numbers 1-5? What are the highlighted areas representing?
1.Doors and fireplaces are two
examples of breaks in wall space
measurements, and receptacles
must be within 6 ft. of each side.
2.Windows do not break a wall
space measurement, even if they
extend all the way down to the
floor. If no room for outlets is
available on the wall, a floor
outlet is an option.
3.Receptacles can be as high as
5 1/2 ft. from the floor and still
satisfy the requirement for
spacing along walls.
4.Wall space measurements
must include distances around
both inside and outside corners.
5.In most habitable rooms, a
guard at the edge of a floor is
considered a wall. Floor
receptacles are the common
design approach in these
instances.
Electrical Systems: Outlets
What are the outlet requirements at countertops?
1.There must be a receptacle within 24 in. from the end of all countertops in front of walls.
2.Sinks and ranges are two examples of a break in the countertop space. Receptacles must be within 24-in. of each side. If there are 18 or more inches behind the sink, a receptacle must be placed there as well.
3.Islands and peninsular countertops that are 12 in. or wider and 24 in. or longer must have a receptacle, typically installed in the side of the cabinet no more than 12 in. below the countertop, which can have a maximum overhang of 6 in.
Image Source: Electrical Outlets by the Numbers - Fine Homebuilding
Electrical Systems: Outlets
What are the outlet requirements at kitchen countertops?
Electrical Systems: Outlets
Which fault circuit interrupter is described below GFCI or AFCI?
- Disconnect power to the circuit when the current leaks.
- Protects the entire circuit, not only a single outlet.
- Help protect a person from dangerous shock or
electrocution. - Can be part of the circuit breaker or installed as a separate
outlet. - Required where any leaking electricity could cause
extreme harm, such as in wet locations. - Per NEC, are regulated in Section 210.8.
Ground Fault Circuit Interrupter (GFCI)
Electrical Systems: Outlets
Which fault circuit interrupter is described below GFCI or AFCI?
- De-energize a circuit when arc faults are detected.
- Prevent fire hazards from arcs in wiring within the wall.
- Required to serve lighting fixtures, generally located in the
circuit breaker panel. - Required for almost all residential lighting and
receptacles as listed per NEC Section 210.12.
Arc Fault Circuit Interrupter (AFCI)
Source: https://www.electricaltechnology.org/2020/06/difference-between-gfci-afci.html
Electrical Systems: Outlets
What is a protection device that offers protection against a ground fault or leakage current?
Ground Fault Circuit Interrupter (GFCI)
It pops off & breaks the supply when it senses any leakage current flowing out from the circuit. This leakage current caused by the ground fault flows through a human body & wet appliance. Therefore, GFCI helps in prevention against electrical shock & that is why they are installed in wet locations such as bathrooms, kitchen, outdoor etc.
It continuously monitors the current going into the load (appliance) “through hot or live wire” & flowing out of the load “through Neutral Wire”. If there is any difference between the two, the GFCI breaks the current supply. The difference occurs due to the leakage current flowing through the grounded body of a person when the appliance comes into contact with water.
Source: https://www.electricaltechnology.org/2020/06/difference-between-gfci-afci.html
Electrical Systems: Outlets
Define:
What is ground fault?
The Ground fault means when the current flows in the unintended path. In a normal situation, the current should flow from the hot wire into the neutral wire. If the current leaks out of the circuit through a ground wire or any person’s body that came into contact with the ground is said to be a ground fault. The ground fault occurs when the phase wire completes the circuit with the ground. That’s why a proper earthing and grounding is needed in each and every electrical installations systems.
Source: https://www.electricaltechnology.org/2020/06/difference-between-gfci-afci.html
Electrical Systems: Outlets
Define:
What is arc fault?
An arc fault is a discharge of a very high power between two or more than two conductors. The arc is generated due to loose cable joints or damage in a flexible cable due to twisting or exposure to heat. Continuous arc generates heat energy that could result in an electrical fire. The arc varies in power & capacity. Normal arcs that are generated every time you toggle a switch or plug a device are not considered as arc faults because they do not cause damage.
Source: https://www.electricaltechnology.org/2020/06/difference-between-gfci-afci.html
Electrical Systems: Outlets
What is GFCI used to prevent?
GFCI is used for prevention of electrical shocks
Electrical Systems: Outlets
What is AFCI used to prevent?
AFCI is used for the prevention of electrical fires.
Electrical Systems: Outlets
What is a protection device that offers protection against arc faults?
Arc Fault Circuit Interrupter (AFCI)
The arc faults are high power discharges between two conductors. The continuous arc can generate enough heat to start a fire & could cause serious damage to property & life. The AFCI breaks the circuit upon sensing any arc in the circuit.
The arcs are generated due to incorrect or loose joints in cables or damaged cables by nail, twisting, kinking, etc. Any loose connection in a power point or old cables may also cause an electrical arc. These continuous arcs can generate enough heat to start a fire & it can disrupt the operation of any sensitive electronic device.
The arcs generate a non-periodic waveform that is detected by using a sensitive logic circuit. It discriminates between a normal arc & an arc fault. As soon as the arc is detected the circuitry trips the power supply but it cannot prevent the first arc. Although it can prevent the ones that follow & avoid a potential fire hazard.
Electrical Systems: Switching
Where do the Energy codes require location of switching in nonresidential spaces?
Energy codes (including IECC and ASHRAE 90.1) require switching in every nonresidential space,
although it is not required to be located near a door.
Electrical Systems: Switching
IRC code for switching locations
Electrical Systems: Sensors
Occupant sensor controls shall be installed to control lights in what spaces?
- Classrooms/lecture/training rooms
- Conference/meeting/multipurpose
- Copy/print room
- Lounges/breakrooms
- Enclosed offices
- Open plan office areas
- Restrooms
- Storage rooms
- Locker rooms
- Other spaces 300 sq ft or less that are enclosed by floor-to-ceiling height partitions
- Warehouse storage areas
Lighting: Daylighting
A client is designing an office space that will harness the daylight. The exterior of the building has windows that start 3’-0” AFF and stop at 8’-0”.
How far into the building can the daylight penetrate the space?
If H= the highest point of the window, the effective daylighting depth is 2.5*H. (H = height from floor to top of window)
2.5 * H = ??
2.5 * 8 = 20 ft
