Untitled Flashcards Set
26108-23 Wire ways, Raceways, and Fittings
EMT (thin wall conduit)(358) is the lightest-duty tubing
-must be installed to provide 1/4” air space between it and the wall or supporting service
-Emt is galvanized
-May be used as a grounding conductor
-Must use connectors and couplings
-installed in masonry concrete(358.42)
-installed in wet locations(314.15)
-NEC 100 defines rain-tight as “constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified testing conditions”
-wet locations
-Unprotected or exposed to weather
Ridged is covered in 344
RMC
-Has a thin coating of PVC
-Good for when the environment calls for the ruggedness of rm and corrosion resistance of rigid nonmetallic conduit
-Plastic Coated RMC instillation
-Chemical plants
- Food plants
-Refineries
-Fertilizer plants
-Paper mills
-Wastewater treatment plants
Identifying Aluminum Conduit
Black Enamel steel conduit
IMC(342)
Thicker than EMT but less than RMC
Weight is 2/3 of RMC
PVC (352)(Rigid Polyvinyl Chloride Conduit)
Noncorrosive ,chemically inert, and non aging
Instillation in wet places
Deteriorates under extreme sunlight
Marked according to NEMA or UL solutions
Cannot be used as an equipment grounding conductor
Sizing(Table 250.122)
Some areas require it to be cut to 10’
Expansion joint
To avoid damage you use expansion couplings(may allow up to 6” of movement )
HDPE(High density polyethylene)
-listed for underground installations
-Suitable for direct burial or encased in concrete
-No listen for above ground use unless encased in 2” of concrete
LFNC (356.10)(Liquid tight flexible nonmetallic conduit)
-Raceway for industrial equipment
-Protects conductors from vapors, liquids, and solids.
-Type A(hose) consists of an inner and outer layer of neoprene with nylon reinforcing web
-Type Most used consists of a smooth wall. Flexible PVC with a rigid integral reinforcement rod
-Type C Nylon corrugated shape without any integral reinforcements
-Is sunlight resistant (176F when dry)(140F when wet)
-3/8-4”
-cannot be used when subject to damage
-Limited in length no longer than 6’
FMC (348)(flex)(Flexible Metal Conduit)
-Non liquid tight and (350) liquid tight
-3/8-4”
-Used to connect equipment or machines that vibrate or move slightly during operation
-Also used to make final connection to equipment with an electrical connection point that is marginally accessible
-Easily bent Should not be bent more than a combination of (360 degrees)
-LMFC used in wet locations
-Support in 348.20 and 250.30
Couplings connects two pipes together
A connector connects a conduit or raceway to a box
A bushing goes on the end of threads to protect the threads and the wires that we pull through the pipe
Threaded weather proof hubs are used in wet locations
Offset Nipples connect two close pieces of equipment where a slight offset is required
Conduit Bodies(conduits are fittings that let you access conduit through a removable cover)
Used in exposed locations
—————
Sealing fittings are required for conduit in hazardous locations where explosions may occur
Clamp back straps can be used with backplate to maintain the 1/4’ spacing from the surface in wet locations
Standoff supports do NOT secure they support
Electrical Framing Channels
- trapeze hanger
Beam Clamps
-used with suspended hangers
Masonry and Concrete flush-mount
-Box’s in concrete are available in up to 6”
-have special breakaway ears
-nailed to wooden forums for the concrete
-
Metal Stud Environment
-5/8
-300.4 protected by listed bushings or grommets
Working in a Wood-Frame
-Edge of drilled hole has to be 1 1/4 from the closest age
-Conduit has to be secured every 10 ft And within 3ft of each box
Metal Buildings
-1 1/2
Zip Ties (Cable ties or tie wraps)
-Zip ties that are ultraviolet are recommended for outdoor use
Bolts and Screws
-
Machine Bolts
-used to assemble parts that don’t require close tolerances
Wood Screws
-used to fasten box, panels, or other materials to wood framing structures
Lag Screws and Shields
-Heavy duty wood screws that provide greater holding power
-Typically used to fasten heavy equipment to wood and concrete when shields are used
-Lag shield is a tube slit lengthwise and I placed in a predrilled hole in concrete(It expands the hole)
Concrete/Masonry Screws(self-threading anchors)
-Used to fasten a device of fixture to concrete, block or brick
Thread forming and cutting Screws
-They form a thread
-Used to fasten light-gauge metal parts
Drywall Screws
-
Drive Screws
-installed by hammering the screw into a drilled or punched hole. Used to fasten parts that will not be exposed to much pressure
Hammer-Driven Pins and Studs
-Can be used to fasten wood or steel to concrete or block without needing predrilled holes
-Should be embedded a minimum of 1/2 in hard concrete or 1 1/14 is softer concrete
Saftey Requirements for Stud type guns
-Powered by powered, gas, or spring
-Load is .22, .25, .27
-12 increasing power loads
-Individuals trained in the use of the particular power tools may use it
-Trained operators must take precautions, to protect themselves and others.
Masonry Anchors
-are used to give fasteners a firm grip in a variety of materials, where fasteners by themselves would otherwise tend to pull out.
-One step
-Bolt anchors
-Screws
-Self-drilling
One-Step Anchors
-are designed so they can be installed through the mounting holes in the component to be fastened
-Wedge anchors
-Heavy duty anchors supplied with nuts and washers
-Stud bolt anchors
-heavy duty and is a good choice when jacking or leveling the fastened component
-Sleeve anchors
-Multipurpose
-One piece anchors
-They work on the principle that as the anchor is driven the spring force of the expansion mechanism is compressed and flexes to fit the size of the hole
-Hammer-set
-Made for use in concrete and masonry
-two types nail and screws
-Threaded rod anchors
-Sammy anchor
-Instillation in concrete, steel, or wood
-Support threaded rod
Bolt anchors
-are designed to be installed flush with the surface of the base material
-
Epoxy Anchoring
-used to anchor threaded rods, dowels, and similar fasteners in solid concrete, hallow wall, and brick
Types of Wireways(376)
-A wire way is a sheet metal trough with a cover used for housing electric wires and cables
-used for housing electric wires and cables
-Rectangular duct type wireways come as either ringed-cover or screw cover troughs
-Rain-tight troughs are used in environments where moisture is not permitted
-When assembling wireways, always place the head of the bolt on the inside and the nut on the outside
-Wireways may only be used for exposed work, cannot be used in under floor installations
-Shall not exceed 20%
-Conductors with slices and taps must not fill the wire way to more than 75%
-Connectors are used to join wire way sections and fittings
Wireways supports
-horizontal wireways runs must be securely supported at each end and intervals no more than 5’
-lengths greater than 5’ must be supported at each end or joint
-Support distance shall not exceed 10’
Specialty raceways(386)
Surface Metal and Nonmetallic
-Carry power and communication wiring to locations on the surface of ceilings or walls on the inside
-Must be installed in dry, interior locations
Multi-outlet Assemblies
-To hold receptacles and other devices within the raceway.
Pole Systems
-Carried from overhead wiring systems to devices that are not located near existing wall outlets or control circuits
Underfloor Systems
-Developed to provide a practical means of bringing conductors for lighting, power, and signaling to cabinets and consoles
-Made with insets spaced every 24”
-Junction boxes are used to to join sections
Cellular Metal Floor Raceways
-precast cellular concrete floors refers to a type of floor used in steel-frame, concrete-frame, and wall-bearing
Duct Systems
-is a single enclosed raceway, or runways, through which conductors or cables can be lead
-can be ran underground
-2”-6”
-Can be made of fiber, vitrified tile, rigid metal, or nonmetallic conduit, or poured concrete
-RNC can be made of PVC, PE, or styrene
Cable trays Types and fittings(392)
-Made from aluminum, steel, fiberglass, and are available in….
-Ladder tray(two parallel channels connected by rungs
-Trough(two parallel channels with a corrugated and ventilated or solid bottom
Cable Tray Supports
-direct rod suspension(uses threaded rods and hanger clamps)
-trapeze mounting(Similar to direct rod but different attachment)
-Center hung
-wall mounting(Attached to wall the support wall support the cable tray)
-Pipe rack mounting (used to support piping that interconnects equipment in outdoor industrial facilities)