Most electronic systems which are responsible for modern advances are based on digital technology. All digital systems, computers and microprocessors are assembled from simple circuits called logic circuits. The basic building blocks of logic circuits are logic gates. And logic gates themselves are simple electronic circuits comprising of diodes, transistors and resistors.
Electrical wiring needs expertise attention to every building projects. It directly related to the safety of human beings and utilities / equipment people handle. The scope of electrical wiring shall cover supply, installation, testing and commissioning of all conduits and accessories, wiring, switches, socket outlets, spur outlets, junction boxes / pull boxes, GI pull wires, ceiling roses making connections etc. This Electrical Construction Article gives comprehensive details of various installation methods, materials used in each installation methods used in building construction projects.
Electrical Engineers seldom show interest acquiring knowledge and experience on cable tray installations. Most of them think it's a concern of mechanical fabricators to be taken care of it. A proper and professional way of cable tray installation requires good involvement and coordination of people from both electrical and mechanical disciplines. If cable tray system has been installed appropriately in a project, following advantages can be counted:
Hence, electrical installation of a project must give high priority to adopt properly evaluated cable tray wiring system if aesthetic impact is low. This article explains how to make a typical method statement for cable tray or trunking installation for a building project.
The scope of work shall cover laying, connecting, testing and commissioning of low voltage power cables complete with all cable support, cable, cable trays, clamps and joints. Cables to be purchased from who regularly engaged in the manufacturer of electrical cable and wire products of the types and ratings required, whose products have been in satisfactory use in similar service not less than 5 years. The standard of the cables shall comply with National Electrical Manufacturers Association of local standards or any other approved.
Component parts of earthing system are to include the following:
The metallic sheath and armour of multicore cables shall be bonded together and earthed.
Cable earthing conductors shall be copper strip with appropriate section laid in formed cable trenches or ducts, or fixed to walls, concrete or steel work, by means of clamps or claw type cleats, appropriately secured into suitable wall plugs or tapped holes. The spacing of fixings shall not be greater than 1 m. Where earth strip is buried or laid in positions in which there is danger of corrosion it shall be provided with a corrosion-proof serving of extruded thermo-plastic or self-adhesive PVC tape which for short lengths may be hand applied on Site.
Earthing or Grounding of Diesel Generator Plant is important to ensure correct operation of the plant and safety of the people who work over there. Generator neutral (star point) is to be connected by insulated earthing conductor through the neutral earthing link or device to main earthing bar. Neutral earthing conductor is to be suitably sized to carry maximum earth fault current for time it takes the system protection to operate with final conductor temperature not exceeding 160 deg. C, but not less than 30 mm2 per 100 kVA of generator rating, with a minimum of 50 mm2. All emergency power diesel gensets including portable gensets to be connected to grounding conductor.
Also read: Guidelines for installing emergency power diesel genset.
Earth electrode resistance, Insulation resistance of factory-built materials installed at the site and Insulation resistance of site-built materials installed at site to be considered individually for field quality control check. It is further to be monitored earth resistance of individual earth unit and combined resistance of earth units.
MV switchgear and MV cables are to have separate main earthing bar connected to framework or earth bar of each item by insulated conductor and the earth-electrode by 2 insulated earthing conductors, one at each end of bar, via testing joints. Earthing conductor is to be minimum 150 mm2.
Every project is unique, in particular, construction projects. There are many methods applied to accomplish functioning of individual installations included in the whole project. Building services like Mechanical, Electric, and Plumbing (MEP) work have given more importance than other disciplines dealt with. It's because of complexity and alternate methods available to accomplish the same output. While executing individual installations - also known as tasks - construction team have to adopt suitable methods submitted as an integral part of Tender. Most of the project managers or representatives of client keen to look Method Statement of critical and important tasks. We will look into what is Method Statement and what is the importance a Method Statement brings to a construction project.
Earthing / Grounding work has to comply with the requirements of General and Technical Conditions of the Project including statutory obligations and regulations. Submittals to be approved by project consultant prior execution of the actual work. Regulations and rules of supply authority also to be considered when preparing the submittals for the local in which installation is being constructed.
Scope of Work of this this sample specification covers the supply, installation, testing and commissioning of all wiring materials for power and lighting in concealed and/or surface conduits.
The conduits shall conform to IS 9537 I & II or equivalent standards. Switches, Plug Sockets shall conform to IS 3854 and IS 4615, however, contractor shall comply with the latest or superseded versions of IS/BIS to be used for the complete work.
Below drawing shows how to install cable tray and its support system. This cable tray support system drawing has Isometric view and cross-sectional view. Following are the steps to be done for laying cables on wall mounted cable tray:
Construction Shop drawings are the actual detail of all manufactured or fabricated items, indicate proper relation to adjoining work, amplify design details of equipment in proper relation to physical spaces in the structure, and incorporate minor changes of design or construction to suit actual conditions.
In this sample MEP specification section, Air Conditioning And Ventilation Installations have been described in detail under construction contract work.
This method of statement specifies the detailed requirements and procedures for the installation of Power and Lighting System Wiring.
Section: Cables and wiring
Division: Installation
Sub Division: Subdivision
WiMAX Broadband Internet is an IP based Wireless Broadband Access Technology utilizing IEEE 802.16e-2005 standard as the air interface. WiMAX will provide broadband connectivity anywhere, anytime, for any device and on any network. WiMAX is a unique technology being deployed by BSNL for the first time in India.
These typical drawings show how to install smoke detectors and heat detectors used in Fire Alarm system on false ceiling. The installation shall be as per the relevant section in the contract specification and drawing has the following major points:
Installation Methods of External, Exterior and Outdoor Lighting System includes lighting equipment luminaires, control gears, panel boards, poles, brackets, cabling, and allied minor civil works. All installations are to be carried out under strict supervision of qualified supervisors and engineers. If installation required heavy vehicles, extreme care has to be taken for preventing damages of lighting equipment, control gears and poles.
Modern Buildings essentially implement the needs of Diesel Powered Electricity Generation Plant. It would become an integral part of the building the day building occupied by its tenants. Here we look into what are the objectives, specifications, services to be considered for functioning complete Diesel Powered Electricity Generation Plant installed in a commercial Building.