Method Statement of LV Cables and Wires Installation

What is the Method Statement of LV Power Cables and Wires Installations?

The method statement of LV power cables and wires installations describes the procedures as per applicable standards, codes, and project specifications.

The scope of this method statement involves the low voltage (≥25V – <1kV) power cable and wires laying activities.

Abbreviations/Definitions

IFC         Issued for Construction
WIR       Work Inspection Request
ITP          Site Inspection and Test Plan
HSE        Health, Safety and Environment
PPE        Personal Protective Equipment
RA          Risk Assessment
MIR        Material Inspection Request
MS         Method Statement
QA/QC  Quality Assurance/Quality Control
PQP       Project Quality Plan
LV           Low Voltage (415 V)
MEP       Mechanical, Electrical & Plumbing

Sequence of Works

The following is the systematic procedure for the installation of LV cables & wires prior to installation, it will be ensured:

All relevant documentation such as approved shop drawings, checklists, approved method statements, material, etc. applicable to a particular section of work will be checked by the site engineer prior to the commencement of work ensuring that these are of the correct type as reviewed by the engineer.

Before the commencement of installation, material inspection will be carried out prior to being withdrawn from the storage area i.e. quantity, physical damage, and brand/make.

Before the beginning of the installation, it will be ensured that the approved valid Permit To Work (PTW) is available on site.

The engineer in charge will ensure that approval and standard tools and tackles are available to carry out the work.

Safe access to work areas will be provided and will be approved by the competent safety person prior to the commencement of work if applicable.

Check the work area tidy and remove flammable materials if any and a safe environment will be ensured.

Where the Risk Assessment identifies high-risk works a permit to work will be obtained from the safety department.

Competent manpower will be employed to carry out the installation work.

Prior to installation, it will be ensured that all the civil works are completed. Necessary civil clearance will be obtained (if applicable) prior to the start of installation.

Material Transport

The material supplied will be packed for protection against damage during handling, transporting, warehousing, and installation.

All the related Low Voltage Electrical Distribution Systems and other related accessories will be handled and transported and unloaded at the site strictly as per manufacturers’ instruction.

After delivery, items will be inspected for any transport both internal and external components casing damage, in compliance with project specification & materials submittal.

Approved shop drawings will be posted at the workplace for site reference used and installation works.

Delivery and Storage

Materials will be delivered, stored and equipment handling will be stored as directed in a neat with safety precautionary measures according to the manufacturer’s recommendation and in accordance with the HSE Plan.

Deliveries will be Inspected and handled at the site area according to the given instructed requirements.

Mechanical handling will be considered prior to manual handling

When materials arrive at the site will be inspected randomly and will ensure that the materials are as per approved material submittals.

Any discrepancies, damage, etc. found to the materials will be notified and reported to QA/QC Engineer and Project Engineer for further action.

All the material will be Inspected and approved by the engineer prior to dispatch to the site and commencement of works.

Materials found not suitable for site use will be removed from the site immediately.

While unloading, shifting, and storage, it will be ensured that there are no damages.

All delivered materials will be inspected on arrival at the site.

All materials will be free from any defects or damages and foreign materials that will result in the inability to install the materials and subsequent deterioration.

Handling

Carefully transport the LV cables & wires to the installation location by means of a boom truck or forklift considering the location of installation.

Forklift and/or equipment to be used for handling the cables & wires will be inspected and will be in good condition.

Delivered materials will be covered with polyethylene sheets while stored to ensure free from dirt and dust.

When off-loading, materials will be lowered and not dropped to the ground.

All materials delivered on-site will have relevant supporting documents complying with the specification of the project.

All incoming panels will be off-loaded by boom truck or manually into the storage area.

Visually inspect the panels for physical damage.

All the materials will be as per the approved material.

No materials will be permitted to enter the work location without prior inspection and approval.

Material Inspection Request (MIR) will be issued and will be inspected by the engineer and approved prior to dispatch to the site and commencement of works.

Site Planning & Preparation

 Before the commencement of installation, the following are required to be carried out.

No one will be allowed to interfere with installation work ongoing or work in the immediate vicinity of installation without a valid permit to work signed by the QA/QC Engineer. This applies to both temporary and permanent electrical installations and equipment.  It is to be done to avoid any damage to electrical cables and wires.

Before the installation of cables and wires, a work permit needs to be obtained and it will be ensured that other MEP services are already installed in the particular section.

It will be ensured that the cable containment system for both normal and emergency power supply is installed and inspected.

Prior to starting the installation, it will be ensured that the latest approved shop drawings/ MEP services coordination drawings related to the installation area are referred to and the required materials are available at the site as per approved material (cables and wires).

Prior to starting the installation, it will be ensured that the latest approved shop drawings / MEP services coordination drawings related to the installation area are referred to and the required materials are available at the site as per approved material (cables and wires).

Check that the ladder/trays are free from any sharp edges and have sufficient space for installing the cables.

20 % spare capacity will be maintained once all cables have been installed on trays.

Trays will not be smaller than the minimum size stated on the drawings or specified later and will be so sized; if not specified, then it will be ensured that the calculated size is large enough for the requirements and provide 20% spare capacity for future use.

For spaces between the cables, while installing, the details mentioned in the approved shop drawing will be followed.

Methodology

Wire Installation

The sub-circuit and final circuit wiring for lighting, small power, and equipment power installation (wire size in mm²) will be accordingly to the schedule provided in the approved shop drawing.

Make sure that all conduits and boxes on both ends are free from damages and blockages etc. and installation is approved.

For longer wire pulling, approved wire-pulling lubricant will be used in the conduit to avoid damage/stress on the wire (if required).

The blockage will be checked by inserting the draw wire and checking that it reaches other ends without any disturbance.

Once the conduit is not blocked the wires will be pulled using the draw wires while ensuring no damage occurs while pulling.

While pulling the wires, care will be taken to not insert the pull tension greater than the manufacturer’s allowed limits.

Refer to the below table for pulling tension and bending radius:

Table1: Maximum Pulling Strength & Bending Radius details (approximate) of cables

 Use the rolling wire drum axle to pull the cable stress-free.

LV Cable Installation

As per the drum schedule and at the location where space is available for working, the drum will be placed on a jack and spindle arrangement to ensure free rotation of the drum.

Erect scaffolding where required as per the site requirement.

The cable will be pulled by using pulling means such as rope, cable-pulling socks, and a winch machine so as not be damage the cable or its containment system.

A cable roller will be placed under the cable during pulling over long distances and a standoff roller for acute bands, to ensure that the cables are pulled with minimum effort and the cable outer jacket is free of scouring lines.

Do not allow the cable to twist or rotate about its longitudinal axis.

Install cables to allow anyone cable to be subsequently removed without disturbing the remainder.

Damage cables will be removed unless the engineer agrees to a repair. Protection of cables against possible mechanical damage will be provided wherever seen to be necessary by the engineer. All cables are to be run with particular regard to neatness. Multiple runs are to be arranged so that cables entering or leaving the run do so in a logical order.

Cable-pulling lubrications can be used where it is difficult to pull the cable or otherwise advised by the Supervisor Engineer. Make sure the lubricant will not deteriorate the cable insulation.

It will be ensured that the correct set and type of reel roller are used for pulling and power cable laying.

The cable will be free of any static load i.e. to be placed side by side parallel on the cable tray or ladders. Any kind of dead weight on the cable will be avoided.

At all-time, the cable schedule & section drawings for the relevant area will be referred to ensure the proper location of cable on the required ladder/tray and to ensure compliance with project specifications.

The cable will be secured to the containment system using approved cable tie/cable cleats for horizontal and vertical runs. The minimum distance between the cable tie will be 0.5m but the details available on the approved shop drawing will be followed.

At the all-time of pulling, mark both power and earth cables for pairing them on both sides of the connection i.e. at sending and receiving ends.

Before termination complete length and route of the cable will be inspected by supervising engineer.

Termination will be done by using the approved termination materials that include glands, lugs, and other accessories part of the termination kit, by using proper crimping tools.

Wire Pulling in Cable Trunk

The following steps will be adopted for pulling wires in the trucking:

Make sure that the cable trunk is inspected for the wire-pulling system.

Make sure that all trunk and terminal boxes on both ends are free from damage and blockages.

Once trunking is checked the wires will be pulled using the draw wires while ensuring no damage occurred while pulling.

While pulling the wires care will be taken to not insert the pull tension greater than the manufacturer’s allowed limits.

Erect scaffolding where required as per the site requirements.

At acute bends to ensure that the cable is pulled with minimum effort, pull manually by using the safely erected scaffolding.

Before termination complete length and route of the wiring will be inspected by QA/QC Engineer.

A separate method statement has been submitted for the installation of the cable tray/ladder.

Before pulling the cable through the tray/ladder, the WIR for the installation of the tray/ladder needs to be approved.

Set up cable stand correctly for even feeding of cable. Each stand will be in line with the other. Avoid the angle at which the cable will be fed from the reel to the tray.

Cable size and routing are as per the approved drawing and the maximum allowable cables in a tray need to be as per the approved drawing.

Use cable roller for cable pull from start to endpoints. Rollers will be placed at every 3 meters (or as close as needed) for the entire length of the pull.

Install a corner-type roller at every corner or bend.

Manually lay the rope above the tray until it reaches the starting point of cable pulling. The rope will be above the rollers.

An approved pulling compound will be used for pulling the cable.

Cable pulling tension will be followed as per the manufacturer’s recommendation.

Manually feed the cable to the tray at the starting point and pull the rope without unreeling cable on the drum to develop certain pressure between the cable and cable stocking until it fully grips the cable.

After checking the grip and that everything is satisfactory, the Site Engineer can give the order to start pulling the cable to the workers assigned at the rope side.

All workers assigned to the cable reel location will manually roll the drum and unreel cable.

During the entire pull, only the person in charge i.e. Supervisor or Foreman will give commands to workers pulling the cable in order to synchronize with the workers releasing cables at the drum end.

The assigned guide will check cable condition at every cable tray corner or offset location.

After the cable has reached the other end, measure the exact length required for termination to the equipment/panel board. Provide enough allowance (slack) for every termination point before cutting the cable at the drum end.

Measure the required length of cable at the drum end to the terminating point and unreel it from the drum. Provide adequate slack also for termination.

Identify cable at both ends for proper identification of cable. The marker sign will be the same as the feeder designation in the cable schedule.

Coil the cable at each end until termination to the equipment/panel board has started.

Cable Joints

Joint in LV cable will only carry out prior approval from the consultant as per the project specification.

Accessories for jointing the cables will be selected accordingly to the approved material.

Check if the appropriate color of the wires has been used from the source to the destination.

Jointing of different colors of wires will not be allowed under any circumstances.

QC inspection will be done after each jointing a continuity and insulation will be conducted.

Identification Cables and Wires

Temporary identification labels and notices will be provided immediately after the installation inspection is approved.
Warning, caution, and instruction notices where indicated in the drawings will be provided temporarily.

It will be ensured that all identification labels and notices are installed in a visible position.

When cable fixing and termination is completed then Permanent label and notices will be provided accordingly.

Tools / Equipment

Measurement tools
Electrical Tool Box
Marker / whitener & line marker
Lugs punch
Cable drum jack
Normal and Right-Angle Cable rollers
Steel pulling wire
Identification tags
Folk Lift
Spanners set
Heat Gun
Cable/wire lubricant (if required)
Multimeter / megger meter
Mobile scaffoldings
Cable winch machine (if Required)
Flags & signboard
Hydraulic Cable Cutter
Hacksaw
Hand shovel
Dynamometer

Materials

UPVC duct and fittings
Cable tray/ladder
All types and sizes of low voltage cables as per approved shop drawings
Cable end caps
Warning tape
Cable cleat
Cable joint kit
Cable support

Quality Control for Method Statement of LV Cables and Wires Installations

The Inspection and Test Plan (ITP) for this method statement summarizes various characteristics to be checked. The concerned Site Engineer or Site Supervisor will be responsible for ensuring compliance with this operation.

The site QA/QC Engineer will carry out quality control checks and report the inspection results.

Quality Records

Quality records will be provided as identified in the ITP and maintained as per ISO 9001/2015, standard form of records, quality checklists, and QA/QC reports requirements.

The submission of as-built records will be done after completion.

tag: Method Statement of LV Cables and Wires Installation