Below electrical method statement briefly describes the installation and testing general requirements on a construction project.
By following below method statement the contractor shall ensure that all the installation works are done as per project specifications and applicable codes and standards.
Below is list of necessary materials tools and equipment’s for the installation and testing:
- Galvanized Iron cable tray
- Nuts & Bolts
- Unifix
- Thread Rod
- Slotted MS Channel
- Spring Nut
- 5mm2 / 4mm2 cable lug and earth wire Y/G cable
- Supports
- 4” Grinder with cutting disc
- Metal Hacksaw Frame with Blades
- Choke Lime powder with sufficient length of thread
- 1 KG Hammer
- Measuring Tape
- Sprit Level
- Drill Machine+ Concrete Bits based on threaded rod sizes.
- Spanner set
- Screw Driver
- Monkey Pliers
- Crimping Tools (1mm to 10 mm)
Necessary Approvals Prior to Installation
All the materials received at site will be inspected, upon receipt.
Any discrepancies, damages, etc. should be notified and reported to the supplier for further action.
Materials found not suitable for site use shall be removed from site immediately.
Work shall not proceed until approved shop drawings or details are issued.
Ensure layout drawings have been approved, and that the latest revisions have been issued.
Material shall be approved prior to procurement. A material approval schedule shall be maintained.
Incoming Material shall be inspected for conformance with the project requirements and LPO (Local Purchase Order), etc.
Check access is available to the areas where installation work is to be carried out.
Coordination with Other Trades
Contractor’s engineer and supervisor shall co-ordinate locations of installation i.e. clearance with other services.
Future disconnection and relocation provisions shall be considered/provided as per the shop drawings, which are to be coordinated and approved by the civil project manager, MEP manager and civil construction manager as applicable.
Sequence of Installation work
Make sure the electrical installation shall be done in accordance with all local and international codes, ordinances, and regulations.
Mount all equipment installed over public areas in a manner adequate to support the equipment loads with a minimum safety factor of five.
Do not use formed eyebolts or lag screws for support of suspended equipment.
Firmly and permanently, attach electrical boxes, enclosures, and permanent equipment to the building.
Rigidly mounted equipment and devices shall be plumb and square.
Choose colors and finishes of all exposed and custom fabricated items and labels to blend in with the surroundings as approved by the consultant engineer.
Install all equipment’s in accordance with manufacturers’ recommendations.
Ensure that levels and impedances are properly matched between components.
Verify that projector distances and lensing are appropriate for the corresponding screen sizes.
Provide shaft locks or security covers on all non-user equipment as directed by the consultant engineer during acceptance testing and equalization.
Ensure that all wireless systems operate on different frequencies from each other and from any other transmitters in the area.
Coordinate frequency selection for compatibility with local RF environment.
Grounding and Shielding:
Mount and enclose all electrical and electronic equipment in metal enclosures or equipment racks.
Mount equipment racks in a manner which provides electrical isolation from the building structure and electrical raceways.
Use flexible conduits and PVC fittings to provide insulated connections between equipment racks and the building electrical raceways.
Ground the chassis of all rack mounted components in accordance with the Drawings and verify D.C. resistance between each chassis and the rack ground bus of no more than 0.0 1 ohms.
Ground the shields of interconnecting wires on one end only and treat the unused opposite ends as described below under wiring practices.
Shield drain wires shall be insulated in all instances by use of appropriately sized black heat shrink tubing equal to Alpha FIT -221 series.
Wiring Practices:
Where specific instructions are not given, perform all wiring in strict adherence to standard broadcast and sound engineering practices as described in the referenced Broadcast Audio Equipment for AM, FM, Television and in Sound System Engineering.
Group all wiring into the following classifications by power level or signal type:
Microphone Level: less than 20 dBm.
Line Level Audio and DC Control Circuits: 20 dBm to +30 dBm.
Speaker Level: greater than +30 dBm.
Video/RF Circuits
AC Power Circuits
Maintain a minimum six-inch separation between wiring of different level classifications wherever possible.
Otherwise, cross them perpendicular to each other.
Where wiring of different level classifications share a common enclosure or junction box, provide metallic isolation barriers to completely electrically separate wiring groups.
Neatly harness wires together within racks by power level classification using horizontal and vertical wiring supports as required.
Rigidly support all wires within twelve inches of connection points.
Observe consistent polarity throughout the audio systems as follows:
a. XLR Type Connectors
1) Positive = Pin 2
2) Negative = Pin 3
3) Common = Pin 1
b. TRS Type Connectors
1) Positive = Tip
2) Negative = Ring
3) Common = Sleeve
Use only balanced differential inputs throughout all sound systems unless noted otherwise.
Use approved transformers to convert all unbalanced inputs to balanced inputs.
Output signals may be unbalanced if inputs of subsequent devices are within the same rack.
Otherwise use approved transformers to balance the outputs.
Exercise care in wiring to avoid damaging the cables and equipment.
Use grommets around cut outs and knock outs where conduit or chase nipples are not installed.
Cut off unused wire ends approximately one-half inch (1/2”) past the wire jacket. Fold them back over the jacket, and secure in place with heat shrink tubing.
Make connections using rosin core solder or approved mechanical connectors.
Do not splice cables of any signal category under any circumstances without prior approval of the Consultant.
All cables shall originate and terminate at active or passive devices; shall not be spliced.
Where several devices are in close proximity, approved housing to housing connectors and adapters shall be used.
All cables terminated in a connection plate mounted in an enclosure shall be dressed to allow removal from the enclosure sufficient cable length for service or re-termination.
Plate shall set on floor or freely swing clear.
All coaxial video or RF connections to plates or panels in boxes, pedestals, racks or any similar location shall be with limited clearance, that would allow the associated cable manufacturer’s minimum bend radius being strictly observed. All shall be provided with the appropriate right angle or similar adapter as appropriate.
Coaxial connectors shall be crimped with the appropriate hexagonal die crimp tool correct for the combination of cable and connector.
Cable Installation in Conduit and Duct Banks:
Pull mandrel one size smaller than the conduit, through entire length of all underground conduits.
Cable pulling lubrication shall be utilized when pulling cable.
A dynamometer shall be used to measure pulling tension during long or difficult runs.
The dynamometer is to be placed between the cable puller and the pull line to monitor pulling tension.
Manufacturer’s pulling tension maximum range shall not be exceeded.
Pulling grips suitable for use with fiber cables shall be applied to the ends of the cable.
Consult cable manufacturer to determine appropriate pulling grip and method of attachment.
Breakaway or fuse links shall be used at the pulling grip.
Insure that the correct “fuse pin” is installed in the fuse link.
Cable caps (heat-shrinking type) shall be used to seal the ends of the cable to protect the cable ends prior to terminating.
Use of cable blocks shall facilitate the bending of cable. For bends between 5 degrees and 45 degrees, a 45 degree cable block shall be utilized. For 45 degree to 90 degree bends, utilize a 90 degree cable block.
The bend radius for all cables shall conform to manufacturer’s specifications.
Provide spare cables between terminal cabinets equal to 10% of the installed cables or a minimum of 2 cables of each type cable installed.
Also provide spare cables between terminal cabinets and equipment racks/consoles equal to 15% of the installed cables or a minimum of 5 cables of each type cable installed.
Label all spare cables as spares with unique identifiers. Do not use any spare cables without prior approval from the consultant.
Labeling the Cables & Equipment Components:
Label product in a logical, legible, and permanent manner corresponding to the drawings using wording, format, style, color, and arrangement of text approved by the Consultant/ Engineer.
Label all panels and wall plates using 118” engraved lettering.
On dark panels and plates, fill engraving with white paint, and on aluminum or stainless steel panels and plates, fill engraving with black paint.
Provide engraved plastic labels similar to Lamicoid, squarely and permanently attached, to label patch panels, barrier strips, terminals, transformers, switches, relays and similar devices as well as the front and rear of all signal processing equipment (e.g., PA, LIM, EQ).
Label all controls on distribution amplifiers, mixers, etc. as to the function of each.
Label push button switches with engraved lettering filled with contrasting color paint.
Label all permanent wiring on both ends with approved permanent clip on type or sleeve type markers.
Wrap around adhesive labels shall not be accepted unless completely covered with clear heat shrink tubing.
The installer should ensure that all wiring complies with the following:
Method of cable support should be such that circuit integrity will not be reduced below that afforded by the cable used, such as termination, distance, etc.
Installation of equipment and devices that pertain to other work in the contract shall be closely coordinated with the appropriate subcontractors.
The manufacturer’s authorized representative shall provide onsite supervision of installation.
Testing, commissioning and handing over the complete installation shall be tested and commissioned by the equipment manufacturer or his representative and the contractor shall demonstrate the operation of the system to the engineer and the client’s personnel.
Inspection, testing and commissioning
All construction/inspection/testing works shall be carried out in accordance with specifications. Work shall be carried out by the site staff under the guidance of respective engineer, and shall further be checked and approved by QA/QC Engineer.
FIELD QUALITY CONTROL:
General Testing Requirements
Maintain a competent supervisor and supporting technical personnel, acceptable to the Owner during the entire installation. Change of supervisor during the project shall not be acceptable without prior written approval from the Owner.
Before connecting any equipment to electrical power outlets, measure and record the A.C. voltages between hot, neutral, and ground and verify correct outlet polarity, Verify test and document correct and safe function of isolated, ground power systems.
Determine the best sequence of energizing systems to minimize the risk of damage.
After successfully energizing the systems, make preliminary adjustments and document the settings of all controls, parameters of corrective networks, voltages at key interconnection points, gains and losses as applicable.
Replicate the unity gain tests performed at the shop and document the absence of any waveform distortion, interference signals, or oscillations.
Upon completion of the system installation, it shall be the responsibility of the Contractor to perform the necessary adjustments and balancing of all signals, amplifier gain, and other level controls to ensure proper system operation.
System shall be physically inspected by the Owner representative to assure that all equipment is installed in a neat and workmanlike manner as called for, by the plans and specifications.
Verify the performance parameters of the individual systems following established professional procedures, in addition to those specified herein.
All test equipment shall be fully charged prior to each day of testing and an appropriate standby alternate power supply source shall be arranged.
Document all acceptance testing, calibration and correction procedures described herein, being careful to include the following information:
Performance date of the given procedure.
Condition of performance of procedure.
Type of procedure, and description.
Parameters measured and their values, including values measured prior to calibration or correction, as applicable.
Parameters associated with calibration or corrective networks, components or devices.
Names of personnel conducting the procedure.
The equipment used to conduct the procedure
Upon completion of initial tests and adjustments, submit written results of tests to Consultant.
In addition, submit written notification that the installation has been completed in accordance with the requirements of the Contract Documents, and is ready for final inspection by representatives of the Consultant and Owner.
All the off cuts of material (steel) will be collected and taken to the environmental waste separation area for recycling purposes. All packaging materials will be removed from the site and maintain safe and tidy workplace.
Chemicals and lubricating oils will be stored within a dedicated chemical store.
MSDS data must be available at all times for perusal by HSE manager, environmental manager and independent auditors.
All chemicals must formally assessed by manager sustainability prior to use.