The primary installation of electrical activity in any construction is installing/fixing conduits for wires and boxes for switchboards. This article details the method to install electrical conduits to comply with applicable standards, codes, and best standard practices
The purpose of this document is to detail the Procedure for the installation of conduits and electrical switch boxes. This procedure applies to the same in concrete walls, slabs, and masonry walls. The documentation will apply to all Engineers, Workmen, QC personnel, and other concerned persons associated with the work.
2. Scope of work
This Procedure covers the applicable codes and standards, seThis Procedure covers the applicable codes, specifications and standards, sequence of work to be followed for the fixing of electrical trades preliminary installation items, manpower requirements, tools and equipment required for the proper execution of works, quality and required to complete the work in compliance to the satisfaction of consultant/client
The scope of work consists of
- Marking and fixing of conduits and boxes in cast in situ
- Marking and fixing of conduits and boxes in embedded walls
- Marking and fixing of conduits and boxes in exposed areas
3. References & Standards
- Project Specific specifications
- IS: 732 – INDIAN STANDARD CODE OF PRACTICE FOR ELECTRICAL WIRING INSTALLATION
- IS: 2274 – INDIAN STANDARD CODE FOR ELECTRICAL WORK SAFETY
- Indian Electricity Act 1910 & Indian Electricity Rules 1956
- Local Electricity Supply Authority and Fire Insurance regulations so far as these becomes applicable to the installation
- IS 4082 – STACKING AND STORAGE OF CONSTRUCTION MATERIALS AND COMPONENTS AT SITE – RECOMMENDATIONS
4. Resources – a) Materials
PVC Conduits of heavy-duty category or as per the specification.
MS Conduits – Solid drawn or lap welded, stove enameled inside and outside with minimum wall thickness of 1.6 mm up to 25 mm diameter and 2 mm for conduits above 25 mm diameter associated with Equipment.
Saddles, junction boxes, sockets, and other accessories
QC Engineers, Electricians, Supervisors helpers and others who directly deal with the responsibility of electrical works
5. Safety Precautions
- Safety of the personnel and properties is to be given prime importance and all works to be carried out without causing any accidents or property damages.
- Materials shall be stacked properly near the place of work (Do not stack too large quantity near the work area thereby causing safety hazard).
- Height of the stack should not be more than one and half meter.
- Scaffolding to be braced adequately.
- Working space to be clear of rubbish, waste mortar etc so that easy access and cleanliness is ensured.
- Throwing of debris from height strictly prohibited.
- Before commencement of work in front of lift shaft safety permit should be taken.
The Project Manager/Construction Manager shall be responsible for the overall implementation of this procedure.
- Approved Good for construction drawing with latest revision issued shall be available with the construction team
- Shop drawings: Shop drawings for conduits and sockets shall be approved, stamped for GFC as per the contractual requirement if any.
8. Equipment and Tools
- Chasing and cutting machines,
- Drill machine,
- Measuring Tape
- Tube Level
- Equipment to enable safe working at height.
9. Inspection of Incoming materials
- Ensuring all the materials delivered to site associated with the activity is inspected and approved. Delivery note, Manufacture’s Test Certificate and any other relevant details are submitted along with a Material Inspection Request Format and approved formally.
- • The conduits shall be delivered to the site of construction in original bundles and each length of conduit shall bear the label of the manufacturer.
- • If any material found to be not as per the approved one or with any damages that can’t be rectifiable will be removed from the bundle/stack and shall be stored separately at a designated area with an identification board viz ‘REJECTED ITEMS’
- • Materials to be stored in dry locations following any recommendation by manufacturer/supplier or as per the standard to protect from mechanical damage or adverse weather conditions.
10. Work Procedure
- Conduit system shall be mechanically continuous and watertight after installation. All conduit system shall be arranged wherever possible to be self-draining.
- Conduits and junction boxes shall be kept in position with proper holdfasts as per the approved details.
- Conduits shall be arranged to facilitate easy drawing of wires through them. Where conduits cross expansion joints in the buildings, adequate expansion fittings or other approved devices shall be used to take care of any relative movement.
- All conduits shall be installed as to avoid steam and hot water pipes.
- After the conduits, junction boxes, outlet boxes and switch boxes are installed in position, their outlets shall be properly plugged or covered so that water, mortar, insects, or any other foreign matter does not enter the conduit system.
- The threads of pipe and sockets shall be free from grease and oil and shall be thoroughly cleaned before making the screwed joints. All joints shall be fully watertight.
- Junction boxes and running joints shall be provided at suitable places to allow for subsequent extension if any, without undue dismantling of conduit system. As far as possible, diagonal run of conduits and adaptable boxes, back outlet boxes, switch boxes and the like must be provided with entry spouts and smooth PVC bushes.
- Joint between conduit and iron clad distribution boards and control gear shall be effected by means of conduit couplers into each of which will be coupled smooth PVC bushes from the inside of box or case.
- Conduit system shall be erect and straight as far as possible. To avoid traps where water may accumulate from condensation and is unavoidable, suitable provision for draining the water shall be made.
- Separate conduits shall be run for 15 amps power outlet wiring. Separate conduits connections for MS conduits shall be screwed metal to metal and be painted with one coat of self-etching zinc chromate primer and two coats of enamel paint. The threads and sockets shall be free from grease and oil.
- Connections between screwed conduit and sheet metal boxes shall be by means of a rubber bush, fixed inside the box and connected through a coupler to the conduit. The joints in conduits shall be free of burrs to avoid damage to insulation of conductors while pulling them through the conduit.
- Conduits for telephone system shall be at least 150 mm away from the electrical conduits.