1 SCOPE
2 REFERENCE DOCUMENTS
3 DEFINITIONS AND ABBREVIATIONS
4 REFERENCE STANDARDS
5 AUTHORITIES AND RESPONSIBIUTIES
6 METHODS AND GENERAL GUIDELINES FOR CONDUIT, SUPPORTS AND IT’S ACCESSORIES INSTALLATIONS
6.1 Quality Requirements
6.2 Above Ground Conduit Installation
6.3 Below Ground Conduit and Outdoor Installation
7 TOOLS AND EQUIPMENTS
8 INSPECTION
1 SCOPE
This Method Statement covers the installation, inspection requirements and to control the erection of conduit, conduit supports and its accessories to be carried out in SEC Construction of – Electrical Installation Works
2 REFERENCE DOCUMENTS
a) Applicable/ Approved International Standards
b) Issued For Construction Drawings
c) Manufacturer Instructions
3 DEFINITIONS AND ABBREVIATIONS
IEC International Electro-technical Commission
NEC National Electrical code
NEMA National Electrical Manufacturers Association
RSI Request for Site Inspection
MRR Material Receiving Report
NCR Non-Conformance Report
4 REFERENCE STANDARDS
NFPA 70 National Electric Code
ANSI C80.1 Rigid Steel Conduits, Zinc Coated
ASTM D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials
NEMA RN 1 Polyvinyl-Chlorine (PVC) Externally Coated Galvanized
RGS Conduit and Intermediate Metal Conduit (IMC)
NECA National Electrical Contractors Association
NEIS 101 Standard for Installing Steel Conduit (Rigid, IMC, EMT
UL 6 Electrical Rigid Metal Conduit-Steel
651 A Types EB and A Rigid PVC Conduit and HDPE Conduit
5 AUTHORITIES AND RESPONSIBILITIES
Site Manager – Determine all requirements needed in order to comply with contractual
requirements and safety standards.
Electrical Superintendent – Ensure that work once started is carried out as planned and that
the applicable standards are complied with. Check working methods and precautions to be
taken by the supervisors/foreman before commencing work.
Field Engineer – Ensure that all related works are carried out in accordance with approved
Released for Construction drawings, specifications, schedule, quality and safety. Report to
Construction Manager.
Safety Officer — Ensure that “Safety, fire, Loss Prevention” program or Safety Plan was been
implemented and monitored.
Supervisor/ Foreman — Supervise all field installations Reports to Electrical Superintendent.
QC Inspector — He shall be responsible for conducting surveillance and inspection duties for
work and ensuring quality compliance and efficient recording and reporting of results as
required. He shall review all relevant documents, material conformance certificates and non
conformance reports and shall receive all internal requests for inspection from various sections
of implementing work and prepare (RSI) Request for Site Inspection as per schedule work
priorities and proceeds the Quality inspection with the client, owner representative as required.
6 METHODS AND GENERAL GUIDELINES FOR CONDUIT. SUPPORTS AND IT’S ACCESSORIES INSTALLATIONS
6.1 Quality Requirements
a) Minimum Size Conduit
• Above-grade: 19 mm nominal diameter, except for lighting fixture stems which may be 13 mm nominal diameter.
• Below-grade: 50 mm nominal diameter.
b) Unless otherwise specified, conduits routed outdoor or indoor for electrical cables will be ERSC. Unless noted on drawings, ERSC will not be used in the following conditions:
• embedded in concrete structures
• through foundations
• direct burial and underground duct bank runs
• in corrosive atmospheres
c) Liquid-tight Flexible Metal Conduit maybe installed in the following:
• Between conduit and conduit boxes of all motors, and any other equipment where vibration may be a problem.
• On equipment which may move due to expansion or adjustment such as motor operated valves or belt-driven equipment, and to equipment which must be capable of ready removal for maintenance.
• Between the rigid conduit and the box or device at all connections to transmitters, pressure switches, and similar field electrical devices.
• Where a conduit crosses a structural expansion joint the length to be of minimum practical length.
• Ground per NFPA 70.
d) PVC will be used on subject to corrosive atmosphere.
e) Group related conduits and support use conduit rack. Provide space as specified in the drawing for additional conduits.
f) Securely affix conduit identification tags in visible locations at each end of the conduit.
g) The conduits for all duct banks will be high grade PVC encased in concrete. Cables under roads will run RCC duct banks with PVC encased in concrete. Conduit mechanical protection will be provided where necessary. Appropriate number, but not < 20% of spare conduits will be provided.
h) Conduit used in non-corrosive environments, in indoor unfinished areas, in hazardous locations and all locations outside the buildings to be constructed of rigid galvanized steel conduit. All conduit supports in such areas will be galvanized steel.
i) Conduits used for lighting, communications, and in finished areas will be EMT conduit.
j) Conduit bushings must be the same type to conduits used for construction. Insulating bushes will be earthing-type with insulating inserts in metal housings.
k) Hanger rods can be galvanized threaded steel rods in non-corrosive atmospheres and
stainless steel rods in corrosive atmospheres.
I) Single conduit supports will be one-hole cast metal straps and clamp backs. Multiple
conduit banks supports to be constructed of support channels and associated conduit
clips.
m) All conduits not located in finished areas or cast in concrete will be routed in exposed
runs parallel or perpendicular to dominant surfaces with right angle turns made of
symmetrical bends or fittings. Conduit to be routed away from the insulated surf ace of
hot piping.
n) All equipment and devices that moves in relation to the supply conduit due to
vibration, normal operation of the mechanism or thermal expansion will be connected
to the supply conduit using flexible conduit adjacent to the equipment or device.
6.2 Above Ground Conduit Installation
a) Prepare all the necessary materials/ tools required.
b) Check availability of all approved Issued for Construction drawings and schedules.
c) Ensure that worksite locations have been released and ready for safe work execution I erection.
d) Verify site access / routing and marked supports locations Follow conduit routing and supports location as per approved Released for Construction drawings.
e) Proper coordination has to be made with other subcontractors to ensure no obstruction or any interference with other services to happen during and / or after the course of erections. Report to ABENER for any conflict for immediate resolution.
f) Any re-routing due to some obstruction will be informed to ABENER for immediate resolution.
g) Install/ erect proper scaffolds/ ladders wherever required for safe installation practices. Safety department before use must approve scaffolds erected.
h) Prefabrication and installation of auxiliary supports will be fixed to structures by means of welding or bolting. Unless otherwise specified, supports will be fabricated on site, starting from structural steel adequately sized for the load of the pipes with cables.
i) Conduits will be connected to cable trough by use of approved earthing clamps attached to the side rail of the trough and tightened around the conduit.
j) Ream to smooth and paint the cut sharp edges of conduits / supports with approved paint.
k) Threading, bending, laying and fixing of conduits: Accurately field measure required conduit lengths. Cut and thread required conduit lengths with either manual pipe threader or electric threading machine. Conduit will be bended by cold method by means of hydraulic bender or motorized bending machines. Bending radius must be observed.
I) Conduit runs will not have more than three (3) 90 degree bends or equivalent between pull points. Conduits for telephone service must contain no more than two (2) 90 degree bends or equivalent between pull points.
m) All connections between pipes and curves made on site will be executed with threaded couplings. If pipes are horizontal they will be laid with level; if vertical they will be plumbed; for other runs, pipes will be laid parallel to the structures. Tighten all threaded connections with proper wrenches and applying approved electrical conductive grease for the conduit connection.
n) Minimum safety clearances to be maintained / observed during installation between conduits / supports and from any other services especially from pipes or equipment with high temperature.
o) Changes of direction in conduit runs will preferably be made in manufactured elbows.
For conduit that must be bent, bending to be done by hickey for small sizes, or hydraulic bender for larger sizes. Bends must be carefully made so as not to cause any kinks, flattening of the conduit, or any changes in internal conduit area.
p) Conduits will be supported adequately as per specifications and approved Issued for Construction drawings.
q) Provide supports as close as possible on 90-degree bends, offsets, change of level, etc.
to ensure rigidity and firm holding of loads Conduit runs and entries to enclosures will be adequately spaced to provide for the installation of conduit fittings.
r) Bushings provided for conduit must be earthing and insulating type. Large parallel runs of conduit will be avoided by using cable trough.
s) The opening around conduits that penetrate an outside wall, fire rated wall or floor will be sealed with grout or approved seals.
t) Provide identification/ labels on conduits.
u) After completion of the work, inspection shall be carried out prior to cable pulling.
v) Marked-up/ As-built drawings for any changes made. Keep clean the area.
6.3 Below Ground Conduit and Outdoor Installation
a) Installation of conduit will be as per approved Issued for Construction Drawing with support details drawing and material specification.
b) Minimum size for below grade conduit will be 1 inch. Below grade conduits to be sized one size larger than required by code maximum wire fill.
c) Reductions in conduit size to be done above grade.
d) Below grade bends will be of the large radius type.
e) There will be no more than three 90° bends below grade conduit run.
f) Spare conduits to be provided with pull cords, terminated with plugged couplings and installed flush with the finished floor in buildings, or 1 inch above the finished surface in other area.
g) Conduits installed outdoors or in high humidity areas where water might enter or condense inside the conduit to be routed into the bottom of enclosures. Conduits entering the top of enclosures in such areas, conduit seals with drain holes will be provided.
h) Conduits embedded in concrete will be rigid galvanized steel conduit Conduit to wire way or cabinet connections outdoors or in wet areas to be made with watertight hubs.
7 TOOLS AND EQUIPMENTS
a) Fitter tool kit
b) Spirit level, Metal measuring tape
c) Combination Pliers
d) Set of Spanner, Adjustable wrench, Set of screw driver
e) Belt wrench, Pipe wrench
f) Pipe cutter
g) Hammer
h) Welding machine
i) Electric Grinding machine
j) Electric Drilling machine
k) Rigid steel threading machine
I) Speed cutting machine
m) Hydraulic bender
8 INSPECTION
All inspections will be coordinated by QA/QC Inspector, who will implement the inspection program and notify all parties involved in advance of the scheduled dates of inspection to enable them to participate. Relevant records to be signed by all the required parties and originals will be kept by the QA/QC Department. Final erection checks to be carried out in accordance with approved ITP. Inspections shall be done per level, area or drawings. Prior to any inspections, verify and check that conduits, supports and accessories are installed in a workmanlike manner as shown on drawings and according to technical and quality requirements.
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