BCN3521 - Exam 1

Arc-Blasts occur when

Tremendous temperatures of the arc cause explosive expansion of both the surrounding air and the metal in the path of the arc

Equipment that is loaded _______ will produce more heat, and the electric material used for these loads must be designed to handle the higher heat loads

continuously

Electrical loads that run ______ will heat up a piece of electrical equipment, but when the load drops allows for the temp to drop

interminttently

Lighting load is found by

largest of either the NEC or Connected Load

In a building, continuous loads tend to be ______

lights

Single or Duplex receptacle has a load of no less than ___ VA per receptacle

180

a continuous load is defined an something that operates at its full capacity for ______ or more continuously

3 hours

_________ nonfatal electrical shocks accidents occur each year

300,000

Arc-Flashes can reach a temp of

35,000 F

If the device contains more than two receptacles, then use ____ VA/receptacle

90

Differences in plugs and receptacles are based on

Ampacity and voltage rating

The rate of electricoty flow is measured in

Amperes (amps)

Majority of hospital admissions are due do? (Shocks, Arc-Flashes)

Arc Flashes

Equipment grounding conductor color coding

Never use insulated conductor that is green or green with yellow stripes for a hot phase conductor

______ are installed to reduce the use of energy and are considered a "green" control

Occupancy Sensors

_____ is a cover placed on a surface mounted box

Raised Cover

____ converts electricity to heat

Resistance

_____ materials are required to install an electrical rough-in

Tabulate

Typical color coding for cable wiring

When wiring with cable (NMC, AC, or MC), choice of colors is limited to those that are furnished with the cable

Tips for Exam

-Be able to read working drawings -Drawings will be on Steinbrenner Hall -Be able to calculate load

Tips for reading electrical working drawings

-Be certain that there is clear understanding of how the system is to be installed -Take special note of long runs of raceway and determine whether voltage drop is a problem

Ungrounded conductor color coding

-Must have outer finish that is other than green, white, gray, or three continuous white stripes -Popular colors are black, white, red, blue, green, yellow, brown, orange, and gray -Conductors 1 AWG and larger are generally available in black only

Switches are divided into two categories

-NEC® 404.14(A) covers ac general-use -NEC® 404.14(B) covers ac-dc general-use

Color coding when there are two electrical systems in one building

-Use white as grounded conductor for one system and gray as grounded conductor for the other system

Most important numbers on nameplate that gives electrical requirements of motors is

-Voltage -Horsepower -Full Load Current

Conductor insulation colors for connecting switches

-When wiring method is conduit or tubing, many colors available -When wiring method is cable, only black, white, and red colors available -Insulation color coding is well established for phase conductors, switch returns, and travelers of electrical systems

______ fatalities each year due to electrocution, more than half of them while servicing energized systems of less than 600 volts

1,000

Outlined in NEC Article 424 for receptacles in electric baseboard heaters

- the requirement for fixed electric space heating equipment -Receptacle may be counted as one of the required outlets for wall space utilized by the heater -Receptacle shall not be connected to heater's branch circuit

Resistance of wet human skin

1,000 Ohms

Arc-Flashes can and do kill a distances of

10 ft

Resistance of dry human skin

100,000 Ohms

GFCI protection is required for all

125-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms, in kitchens, on rooftops, outdoors, and within 6 ft (1.8 m) of any sink

Used to protect against the possibility of electric shock

15- and 20-ampere branch circuits can be protected with GFCI receptacles or GFCI circuit breakers

NEMA terminal identification for receptacles (What is the brass label for?)

Connect HOT conductor to this terminal (black, red, blue, etc). There is no NEMA standard for a specific color conductor. It is good practice to pick a color code and stick with it

NEMA terminal identification for receptacles (What is the white/silver label for?)

Connect white or gray grounded circuit ONLY to this terminal

Load of what is actually connected, calculated by number of fixtures and connected load for each

Connected load

Ohm's Law is

Current = Voltage/Resistance

NEMA terminal identification for receptacles (What is the green label for?)

Has hexagon shape. Connect equipment grounding conductor ONLY to this terminal

In a building, HVAC is typically a ____ load

Intermittent

Type of receptacle used to (an insulated grounding conductor is run from neutral terminal at the main service entrance to the isolated ground terminal on the receptacle)

Isolated ground receptacle

The allowable load specified by per (floor, equipment, etc) for lighting

NEC load

Resistance of punctured human skin

500 Ohms

Location not normally subject to dampness

Dry

What NEC code lists different items that are considered acceptable equipment grounding conductors

NEC® 250.118

Grounded conductor color coding

NEC® requires that grounded (identified) conductor have an outer finish of either continuous white or gray color, or have outer finish that has three continuous white stripes

Typical color coding for conduit wiring

-Color coding is not code mandated -Be sure not to use white, gray, green, and bare conductors other than for their permitted uses -CAUTION: In old installations, conductor having gray insulation was sometimes used as ungrounded "hot" conductor

4 safety procedures

-De-energize circuits before working -Lock out/ Tag out -Justify working on live circuits -Provide proper PPE

How to ground snap switches

-Metal box is considered adequately grounded provided the metal raceway, Type AC or Type MC, is properly grounded at its origin -Metal yoke of snap switch is considered grounded when secured by metal screws -Metal faceplate is considered grounded when secured to metal yoke of snap switch

When electric current passes thru air between conductors

Arc-Flash

locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture

Damp

Load used by appliances and other equipment that connects to the general purpose receptacles in a building

Duplex

Type of receptacle used to reduce "noise," circuits with receptacle outlets that serve loads such as computers or other sensitive electronic equipment should be supplied by isolated ground receptacles

Electronic equipment receptacle

_____ is a cover placed on a recessed box

Faceplate

_____ leading cause of industrial fatalities, after traffic, homicide, and construction accidents

Fourth

_____ developed standards for receptacles

NEMA, National Electrical Manufacturers Association

Disturbances that call for grounding of electrical equipment

Voltage sags, spikes, and surges Static charges Lightning strikes and surges on the system Electromagnetic interference (EMI) Radio frequency interference (RFI) Improper grounding

installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather

Wet

an electric water heater with a capacity of 120 gallons or less is considered a _____ load

continuous