CHAPTER 2, ENCLOSURES AND RACEWAYS Flashcards
• are ELECTRICAL BOXES and CABINETS that are made of metal or non-metallic materials that protect conductors, connections, controls, and other equipment
• they protect wiring, devices, and equipment from damage from accidental contact, wear, corrosive, atmospheric exposure, and sunlight
• for faulty enclosed conductors, connections, controls, and electrical equipment, enclosures contain the arc and
flaming, thereby confining damage from fire
enclosureS
• are METAL AND NONMETALLIC ENCLOSURES that hold devices such as switches or outlets and safety PERMIT wiring connections
• boxes are in four primary shapes: square, rectangular, octagonal, or round
• boxes can be joined together to accommodate multiple outlets or switches, namely; two-gang, three gangs, or four gang boxes
electrical boxeS
• special type of electrical box used to ENCLOSE CONDUCTOR CONNECTIONS
• connections are commonly called junctions in the trade
junction boxeS
kind of junction box that allows access to a raceway for
SNAKING conductors through the raceway
pullbox
in most boxes and enclosures, it can be EASILY REMOVED
to allow wiring to enter the box
knockout
• required for various single or combinations of switches, convenience outlets, blank covers, and dimmers; plastic is a commonly used material
• attached with screws to the switch or receptacles
• all the boxes should be finished with a cover plate
cover plateS
• an ENCLOSED CHANNEL such as conduit, tube, or gutter used for holding WIRES, cables, or bus bars
• in some cases, metal __________ that are fully bonded serve to provide a path for the flow of fault current to
ground
RACEWAY
- a HEAVY GALVANIZED STEEL or aluminum tube that looks like the galvanized steel pipe used for plumbing applications, except it is much smoother and is labeled with a UL Listed stamp or label has THREADED connections much like a pipe
- can be used in contact with the earth and embedded in concrete
RIGID METAL CONDUIT
• galvanized steel or aluminum tube that has a thinner wall than rigid metal conduit
• has threaded connections much like pipe or threadless connectors and couplings
• can be used in contact with earth and embedded in concrete
INTERMEDIATE METAL CONDUIT
• THIN _ WALLED GALVANIZED STEEL or aluminum tube in nominal diameters up to 4 in.
• CANNOT BE THREADED
• labeled with UL Listed stamp or label
• joined with threadless compression couplings, couplings that are crimped into the tubing with a special indenting tool, or fittings that are TIGHTENED WITH SCREWS
ELECTRICAL METALLIC TUBING
• a FLAME - RETARDANT corrugated plastic tube that is semi flexible such that it can be bent by hand. • must be used behind fire-rated finish materials
• permitted in damped locations and can be set in concrete above ground
• can also be solvent welded to rigid _____________
(PVC) conduit
• can be used in any building, but special precautions are required when used more than three floors above grade
ELECTRICAL NONMETALLIC TUBING, polyvinyl chloride
• THIN WALLED PIPE OF PVC
- joined with fittings that are SOLVENT WELDED
RIGID NONMETALLIC CONDUIT
similar to armored cable yet, installed without cables or wiring in it; wiring must be pulled
FLEXIBLE METAL CONDUIT
similar to flexible metal conduit but covered with plastic, a WATERTIGHT JACKET that is sunlight resistant
• unlike flexible metal conduit, the special connectors are watertight
LIQUID TIGHT FLEXIBLE METAL CONDUIT
• a flexible plastic conduit used similarly to flexible metal conduit
cannot be used over 6 ft. in length
LIQUID TIGHT FLEXIBLE NONMETALLIC CONDUIT
are hollow voids in floors made of precast concrete slabs (core slabs) found in certain precast concrete buildings
cellular concrete floor racewayS
• involves cutting, bending, and threading lengths
EMC, EMT, ENT
• a run of conduit should be straight and direct
so true
_________ or __________ must support the conduit in the entire run
strapS , hangerS
• the number of conductors in a raceway is based on the
size of the conduit,
type of conductor insulation,
size of conductors
• several conductors fed into conduit should be kept
___________, _________, and _________ and _____________.
parallel, straight, and kinks and bends-free
• is of a standardized, factory assembled enclosure consisting of outer DUCT LIKE HOUSING, BUS BARS, and INSULATORS
•__________ systems are used in service equipment or as __________ because they are designed to carry a large amount of current
BUSWAY, feeders
A type of busway system that used to deliver a LARGE AMOUNT OF POWER with LOW VOLTAGE DROP • available in sizes from 600 A to several thousand amps
FEEDER BUSWAY
• Another type of busway system used to provide POWER TAP-OFFS at multiple points • available in 100 A- 3000 A sizes
PLUG-IN-BUSWAY
