Below is a precise electrical method statement that covers all processes related to the installation of PVC, GI, RGS, EMT and steel conduits and boxes as per project specification, manufacturer
recommendation, approved drawings, civil defense approval and any other applicable regulations.
The manpower and time scale required depends upon the number of conduits and boxes which will be installed in different projects.
All the materials shall be as per project electrical specifications and approved material submittals for different materials.
Tools & Equipment
Following tools shall be arranged before starting the job.
- Drill / grinding machine
- Portable hand tools
- Electrician Toolbox
- Mini Hacksaw Frame with Blades
- Measuring Tape
- End Cutter
- Ladder/Scaffolding
- Hammer
- Centre punch
- Spirit level / Water Level
Sequence of Work
PVC, HEAVY GAUGE PVC and Flexible EPVC Conduit Installation
Ensure that the work site locations have been released and ready for safe works execution especially the wall surface where boxes and conduits are to be installed.
Survey and mark out the exact location of all conduits and boxes in ceiling or wall as per approved drawings.
Follow all the distances, height and marking given in the approved layout & detail drawings.
Rigid heavy duty PVC conduits shall be used for Lighting and power systems, Low current systems, above false ceilings and embedded areas as per project specifications and approved shop Drawings.
Expansion ring, PVC boxes, adopters, male bushes, locking nuts shall be utilized as per approved shop drawings.
Expansion coupler shall be utilized at locations where PVC Conduits are crossing construction expansion joints.
Connect conduits terminating in switchgear, fuse boards, trunking, adaptable boxes or other non-spouted enclosure with smooth bore male PVC bushing and sockets.
Ensure that conduit connections are tight and fixed rigid.
The outlets shall not run more than the permissible numbers of conduits to any surface wall outlet.
Exposed conduit work is to be installed so as not to interfere with ceiling inserts, lights or ventilation ducts or outlets.
Use approved hot bent method to bend the PVC conduit if conduit over 25 mm and below 25 diameters use cold bent by bending spring.
The conduits on walls are to be run neatly, horizontally or vertically.
Provide pulling wire (GI wire or equivalent strength cord) in each conduit.
Secure the wire inside the box or at end of conduits and cover properly.
Any changes in the routing of conduits shall be mark in the as built drawing.
All installed conduits to be protected until the next activity and final handover.
Steel Conduit Installation (RGS and Heavy Gauge Rigid Steel)
Electrical Metallic Tubing (EMT) shall be used for exposed fixings and above false ceiling wherever applicable as per the project Specifications and approved Shop drawings.
Rigid heavy gauge steel / RGS conduit is used for all exposed installation such as mechanical, electrical equipment rooms and all hazardous area.
Expansion arrangement shall be made for RGS & EMT conduits when crossing expansion joints.
Wall shall be painted minimum first coat of approved paint before installing the boxes and conduits.
Survey and mark out the exact location of all boxes in ceiling or wall follow all the distances, height and marking given in the approved Shop Drawing and IFC drawing.
After verifying the exact location and provided all the necessary mark out, start installing the box by drilling in the concrete wall, column or ceiling and fix the box.
Ensure that the boxes are inspected for alignment, height, distances, flatness after fixing and bolts/screw are securely fastened.
After completing the installation of the box, start fixing the conduits, conduit shall be securely fastened in wall.
Where a conduit is placed in a sheet metal enclosure or outlet boxes it shall be securely fixed using Locknuts arrangements.
Ensure that conduit threads are properly cut. Conduit shall be cut using a saw or a roll cutter (pipe cutter). Care should be taken to ensure a straight cut. After cutting end conduit fittings are to be
cleaned, cut ends are to be reamed to remove burrs and sharp edges.
Where a conduit enters a box, fitting, or other enclosure, a bushing & locknut shall be provided to protect the wire from abrasion unless the design of the box, fitting, or enclosure is such as to afford equivalent protection.
Thread less couplings and connector used with conduit shall be made tight.
When installed in open area, the boxes and conduit connections shall be weatherproof type.
Thread less or screw type coupling and connectors shall not be used on threaded conduit ends unless listed for the purpose.
All the threads of plugs, junction boxes and other fittings shall be lightly lubricated with rust preventive grease before assembly.
Provide pulling wire (Gl wire or equivalent strength cord) in each conduit. Secure the wire inside the box or at end of conduits and shall be covered.
Channel erector system components (Unit strut or similar) used to support conduits, cable trays, enclosures, lighting fixtures and other electrical equipment shall be made hot-dip galvanized (preferably).
All field cuts unit-strut shall be touch up with approved paint.
Remaining threads on galvanized steel conduits are to be filled with touch up paint.
Any changes in the routing of conduits shall be mark in the as built drawing.
Embedded Conduit Installation in Slab and Walls ( PVC/RGS)
PVC conduits in reinforced concrete structures are generally to be installed after placing reinforcement and before concreting, using the steel boxes and fittings such as coupling, adapters with locknuts, and PVC solvent.
Sizes of conduits and boxes to be installed as per approved shop drawings.
PVC Conduits shall only install embedded in concrete slab or block work, exposed PVC conduits works is not permitted.
Survey and marks out the exact location of all boxes, conduits in the slab and walls.
Ensure the coupling of conduit and termination into spouted fittings is to be made watertight and permanent using special cement.
Check and ensure bending of conduits is done using appropriate methods without compensating the internal diameter of conduits.
For bending purpose only bending spring or PVC elbow shall be utilized.
Ensure that the connection of the conduit terminating in switchgear, fuse boards, trunking adaptable boxes or other non-spouted enclosures etc., with smooth bore male PVC bushes and sockets.
Make sure that the semi-permanent adhesive is used in joints requiring expansion couplers.
Ensure the ends of conduit and conduit fittings are to be cleaned and jointed using PVC cement recommended by manufacturer.
All unused openings inside a box shall be closed using masking or duct tape.
Provide pulling wire (GI wire or equivalent strength cord) in each conduit. Secure the wire inside the box or at the end of conduits.
All conduit stubs up are properly capped until wiring conductors are drawn in.
Installed conduits shall be protected from dust, dirt or damages until the next activity and final handover.
Any changes in the routing of conduits shall be marked in the as built drawing.
Inspection Checklist for Conduit Installations
The conduit, boxes and fittings shall be given a visual inspection by the Engineer during the installation.
Contractor should not allow any backfilling of trenches or pits where these systems are installed before inspection by the Engineer and the appropriate documents are signed.
Material delivered shall be inspected under the Engineer’s supervisor about size, quality and quantity.
Shop drawing shall be approved.
Materials shall be approved.
Check installation (connection, routing, and quantity) according to approved shop drawings.
Make sure dimension, level and finishing of conduits, boxes and fittings.
All equipment’s connected to power supply must be grounded.
Metal parts, structural steel, cable trays, piping, reinforced concrete must be grounded.
All joints shall be according to shop drawing.
Check installation according to approved shop drawings and manufacturer’s recommendation