WIRES, CONDUITS AND RACEWAYS Class Instructor : VINCENT J. DAYAG JR,MSArch.UAP.PIEP. Architect / Environmental Planner

GENERAL WIRING Trade Name Type Maximum Operating Procedure C - F Location Moisture and Heat Resistance Rubber RHW Dry and wet ThermoplasticT 60 – 140 Dry Moisture Resistant Thermoplastic TW 60 – 140 Dry and wet Heat Resistant Thermoplastic THHN 90 – 194 Dry Moisture and Heat Resistant Thermoplastic THW THWN 75 – 167 Dry and wet Moisture and Heat Resistant cross linked With Thermosetting Polyethylene XHHW 90 – 194 Dry and wet Silicone Asbestos SA 90 – 194 Dry Asbestos and Varnished Cambric AVA Dry

COPPER AND ALUMINUM CONDUCTORS Both have lower installation cost. Copper is preferred over aluminum in all preferences. Aluminum is lighter than copper, but forms an oxide causing poor conduction. Aluminum conductor is restricted to sizes not smaller than #AWG.

FLEXIBLE METAL CLAD ( BX ) Assembly of wires of plastic insulated bound together with a tape or braid wrapped with a spiral wound interlocking strip of steel tape. Installed as a unit, with U – clamp or staples against walls, ceilings and columns. Used for residences and re – wiring of existing buildings.

FLEXIBLE METAL CLAD ( BX ) Can be pulled into place through existing spaces in back of plastered surfaces, under floor joists or between studding in walls. Provided with special couplings, box connectors and other fittings to interconnect BX with RSC’s.

BUSWAY / BUSBARS / BUSDUCT To carry large amounts of current or power require high - current carrying application. Carrying capacity of copper bus is 1000A/sq.inches to safely carry 500 Amperes. Sizes vary from ¼ “ x4” / 5/16”x6”

BUSWAY / BUSBARS/ BUSDUCT Bus is made from solid copper and assembled in metal housing ( busduct ). Bus is made from solid copper and assembled in metal housing ( busduct ). Bolted in connection with stiff metal housing installed with angles, bends, tap – offs and curves. Plug – In refers to a design that allows devices such as switches and circuit breakers directly plugged into the busduct.

CABLEBUS Similar to busway except that it uses insulated cables rigidly mounted in open space frame. Carries higher ampacity in free air than in conduit rating.

CABLEBUS Allows the change in feeder length Allows a number of taps Sustain hours of operation Less energy rates

ASSEMBLIES Flat Cable Assemblies Lighting Track Cable Tray Open Raceway

ASSEMBLIES FLAT CABLE ASSEMBLIES -Field constructed -Consist of 2 – 4 conductors -Connection extend directly to the device or to an outlet box with receptacle for easy disconnection. -Useful for small unit heaters or single phase light duty services -Eliminates the necessity of hard conduit / cable wiring.

ASSEMBLIES LIGHTING TRACK -Factory assembles channel with conductors for 1 – 4 circuits permanently installed in the track. -Power is taken from track by special tap – off devices that contact the track electrified conductors and carry power to the attached lighting fixture generally rated 20A unlike FC assemblies that is restricted to 120V.

CABLE TRAY / OPEN RACEWAY Continuous open support for approved cables. Requires that cables be self protected or jacketed types. Free air rated cables, easy installation, maintenance and relatively low cost but bulky and require special access. Cable Tray Open Raceway

CLOSED RACEWAY Three variations are: 1.Conduit pipes 2.Surface raceways 3.Under - floor ducts

STEEL CONDUIT Protect and enclose wiring from mechanical injury and corrosion Provide grounded metal enclosure for the wiring in order to avoid shock hazard Provide a system ground path

STEEL CONDUIT Protection from fire hazard, overheating or arcing of the enclosed conductors Support the conductors Made from : -Hot Dip ( galvanized into molten zinc ) ( galvanized into molten zinc ) -Enameled ( coated with corrosion – resistant enamel ) ( coated with corrosion – resistant enamel ) -Sherardized ( coated with zinc dust ) ( coated with zinc dust ) -Plastic covered