2. LEARNING OBJECTIVE:
AT THE END OF THIS SESSION, YOU WILL BE ABLE TO:
•IDENTIFY PROPER USAGE AND TYPES OF CONDUITS IN ELECTRICAL
INSTALLATION.
3. INTRODUCTION
AN ELECTRICAL CONDUIT IS AN ELECTRICAL PIPING SYSTEM USED FOR PROTECTION AND ROUTING OF
ELECTRICAL WIRING. CONDUIT IS GENERALLY INSTALLED BY ELECTRICIANS AT THE SITE OF INSTALLATION OF
ELECTRICAL EQUIPMENT. ITS USE, FORM, AND INSTALLATION DETAILS ARE OFTEN SPECIFIED BY WIRING
REGULATIONS, SUCH AS THE NEC OR PHILIPPINE ELECTRICAL CODE. THE TERM "CONDUIT" IS COMMONLY
USED BY ELECTRICIANS TO DESCRIBE ANY SYSTEM THAT CONTAINS ELECTRICAL CONDUCTORS, BUT THE
TERM HAS A MORE RESTRICTIVE DEFINITION WHEN USED IN WIRING REGULATIONS. HERE THE DIFFERENT
TYPES OF ELECTRICAL CONDUIT.
5. RIGID STEEL CONDUIT (RSC)
A RIGID STEEL CONDUIT SERVES THE SAME PURPOSE AS WITH THE ELECTRICAL METALLIC TUBING. IT IS
DESIGNED TO PROTECT THE ELECTRICAL WIRING OF BUILDING FROM ELECTRICAL HAZARD DUE TO FAULTY
WIRING. IT IS USUALLY INSTALLED BURIED IN CONCRETE WALL FLOOR AND CEILING, IN MASONRY OR
SIMILAR MATERIALS. IT IS ALSO USED FOR EXPOSED AND CONCEALED WORK, AND IT PROVIDES MAXIMUM
PROTECTION WHEN THERE IS MECHANICAL DAMAGE. FOR THIS WIRING METHOD TO BE EFFECTIVE, SAFE
AND RELIABLE, IT IS A MUST THAT IT SHOULD FOLLOW THE PHILIPPINE ELECTRICAL CODE (PEC) STANDARD
AND SPECIFICATIONS.
7. INTERMEDIATE METALLIC CONDUIT (IMC)
INTERMEDIATE METALLIC CONDUIT, OR IMC, IS A THINNER, LIGHTER-WEIGHT VERSION OF RIGID METAL
CONDUIT AND IS APPROVED FOR USE IN ALL OF THE SAME APPLICATIONS AS RSC. BECAUSE IMC IS LIGHTER
AND EASIER TO WORK WITH THAN RSC, IT IS USED MORE COMMONLY IN NEW CONSTRUCTION.
9. ELECTRICAL METALLIC TUBING (EMT)
ELECTRICAL METALLIC TUBING IS A TYPE OF WIRING INSTALLATION WHICH IS DESIGNED TO LESSEN OR
ELIMINATE FIRE HAZARD AND ELECTRICAL ACCIDENT. MAY BE USED FOR EXPOSED AND CONCEALED WORK AT
THE SAME CONDITION WITH RIGID METAL CONDUIT. EMT IS PROTECTED WITH ENAMEL SHOULD BE USED ON
THE FOLLOWING CONDITIONS:
• SUBJECTED TO MECHANICAL DURING OR AFTER THE CONSTRUCTION
• CINDER FILL
• HAZARDOUS LOCATION
• EXPOSE TO CORROSIVE FUMES AND VAPOR
11. METALLIC FLEXIBLE CONDUIT
FLEXIBLE METALLIC TUBING IS A KIND OF WIRING INSTALLATION WHICH IS COMMONLY USED FOR EXTERNAL
MOTOR TERMINAL CONNECTION. IT IS BEING MANUFACTURED IN ROLLED IN THE FORM OF COIL. A FLEXIBLE
CONDUIT CONSISTS OF FLEXIBLE STEEL TUBE WHICH IS MADE FROM CONVEX TO CONCAVE METAL STRIP IN
A SPIRAL WINDING. FLEXIBLE METALLIC CONDUIT IS USED IN A CONNECTION WHERE THE LOAD BEING
SUPPLIED NO DEFINITE PLACE WHERE FLEXIBILITY IS DESIRED. SOME COMMON EQUIPMENT ARE THE
PORTABLE MOTOR, DRILL PRESS LATHE MACHINE, ETC.
13. NON- METALLIC NON- FLEXIBLE CONDUIT
IS NON- METALLIC UNTHREADED SMOOTH- WALLED TUBING. THEY ARE MANUFACTURED TO BE
RESISTANT TO MOISTURE AND CHEMICAL ATMOSPHERE, FLAME RETARDANT. THEY ARE RESISTANT TO
IMPACT AND CRUSHING AND, THEY DO NOT EASILY GET OUT SHAPE BECAUSE OF HEAT. THESE
CONDUITS ARE CLASSIFIED ACCORDING TO THE MATERIALS THEY ARE MADE OF.
• POLYVINYL CHLORIDE (PVC)
14. POLYVINYL CHLORIDE (PVC) PIPE
• THE PVC PIPE IS ONE OF THE MOST COMMONLY USED CONDUITS IN ELECTRICAL WIRING INSTALLATION
TODAY. ITS PREPARATION FOR INSTALLATION IS MUCH EASIER THAN THE METALLIC RIGID CONDUIT. IN
PREPARING A NON- METALLIC RIGID CONDUIT FOR INSTALLATION, AN ELECTRICIAN NEEDS TO DO
CUTTING, HEATING AND BENDING. LIKE IN METALLIC RIGID CONDUIT OFFSET BENDS, 90° ANGLE BENDS
AND OTHER BENDS ARE ALSO MADE ON PVC RIGID CONDUIT. IN MAKING BENDS ON PVC RIGID CONDUIT,
THE ELECTRICIAN SHOULD SEE TO IT THAT THE INTERNAL DIAMETER OF THE CONDUIT IS NOT REDUCED
AND DAMAGED SO THAT THE CAPACITY OF THE CONDUIT TO ACCOMMODATE MAXIMUM NUMBER OF
CONDUCTORS WILL NOT BE LESSEN AND TO FACILITATE EASY PULLING OF CONDUCTORS.
16. NON- METALLIC FLEXIBLE CONDUIT
FLEXIBLE NONMETALLIC CONDUIT IS USED AS MECHANICAL PROTECTION FOR ELECTRIC CONDUCTORS. IT HAS A
SMOOTH INTERIOR AND A WALL OF NON-CONDUCTING FIBROUS MATERIAL. THIS IS COMMONLY USED ELECTRICAL
WIRING CONDUIT NOW A DAYS DUE TO ITS ECONOMIC VALUE.
