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.
At the completion of the electrical installation works, the entire installation shall be subject to the test before final placing in service under the full responsibility of the contractor. Unless Otherwise specifically called for all tests shall be carried out in conformity with IEE regulations. Contractor shall coordinate with the Client and the Supervising Engineer to get electricity from the local supply authority before starting of testing and commissioning.
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.
First of all, we have to look into what is the definition of Appliance in-general and specifically for Electric Appliance.
Definition of Appliance
What is the definition of Appliance? The term appliance can be defined as, "a device or apparatus or equipment designed to perform an application or task, other than industrial, benefited in our personal life that uses some kind of technology". In short, an appliance is a machine that reduces a human’s effort in carrying out a specified work or task. For example, a scissor uses to cut our hair, an iron box to ironing our clothes, a TV to watch entertainment programs and news form different parts of the world. Here, scissor uses mechanical technology to perform its function. It uses only mechanical energy that generated by parson it operates, where as, other two appliances use electricity as the source of energy to operate it. Appliances may be indoors or outdoors, fixed or portable or hand held or hand operated or remotely operated or computer controlled and there on.....
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:
- Cable Tray system enhances safety of electrical wiring system.
- Cable tray installation provides dependability in any circumstances.
- Cable Tray system saves space, materials, labor, time and cost.
- Maintenance and extension of cable tray installation are easier than any other wiring system.
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.
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.
1. Applicable Standards
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.
These drawings show how to install Fire Alarm Break Glass (BG) or Manual Call Point (MCP) on walls. It has to be mounted on back box installed in the wall. This box (embedded or exposed as specified in the concerned section of the specification) has to be connected through GI / PVC conduit that will have the Firetuff or equivalent cable to be looped for other detectors. Conduit end to be taken out of the wall above false ceiling to allow the Firetuff cable to be clipped on soffit of the slab.
Drawing below shows how to install Manual call point break glass along with a sounder
In this typical drawing, manual call point break glass unit has been shown as concealed and the rest are surface installed in the false ceiling. Sounder has been mounted on ceiling but can also be mounted on wall visibly as per the project specification.
The value is a function of cost. Therefore, it can be increased either by improving the function or reducing cost. The maximum value is achieved when the function performs reliably at the lowest cost. A key principle of value engineering that basic functions be preserved and not reduced as a result of improvements in value. Thus Value Engineering (VE) is a systematic method to improve the "value" of goods, products or services through an examination of the function.
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.
Fire Alarm System installation work covered by this section of the specifications includes the furnishing of all labor, equipment, materials, and performance of all operations in connection with the whole Fire Alarm System as shown on the drawings and as herein specified. The requirements of the conditions of the Contract, Supplementary Conditions and General Requirements apply to the work specified in this section.
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.
We often depends Diesel Electrical Genset as emergency power system due to mains failure. As a professional, the installation of diesel electrical power generator should be as per the clients requirement and to be inline with the authoritative norms and standards. Safety, security, convenience, future expansions etc are to be considered and co-ordinated before start detailing of the genset's installation. The generator should be as close to the main change-over board as possible. In cases like Textile Mills, where there is fear of smoke affecting the quality of the yarn etc., generators may be located away from the Plant / Department.
In this sample MEP specification section, Mechanical Ductwork, Grilles And Diffusers have been described in detail under construction contract work.
Main Highlights of this MEP Specification
- Mechanical Ductwork
- Mechanical Ductwork Supports
- Mechanical Dampers - General Requirements
- Flexible Joints for Mechanical Ductwork
- Air Intakes and Outlets
- Kitchen Extract Canopies
- Kitchen Extract Air Ductwork
- Access Doors
- Ductwork Test Points
- Ductwork Protection
- Sand Trap Louvres
- Air Valves
- Fire Dampers
It is essential that services and systems in a building construction contract work are provided to conform to the requirements of the customer, and that the activities be effected as economically as practical. The achievement of these objectives is facilitated by setting up working procedures and practices, which collectively provide a “Work Efficient”, yet controlled operating environment. It is the purpose of this Construction Quality Plan to give instruction to personnel, on the implementation of the company system such that the above objectives are accomplished. Documentation specific to the project will be provided to ensure full compliance with the particular requirements of the contract.
Fire alarm systems have become increasingly sophisticated and functionally more capable and reliable in recent years. They are designed to fulfill two general requirements: protection of property and assets and protection of life. As a result of state and local codes, the life-safety aspect of fire protection has become a major factor in the last two decades.
Low Voltage Switchgear are familiar to every people since they are the controlling mediators between low voltage utilities and equipment with human beings. Be it a common home DB or an isolator or control centres, they all are being manufactured to use untrained people ie., common people. The scope of works shall cover the supply installation, testing and commissioning of main and sub-distribution boards, panel boards, fusible safety switches, circuit breakers etc. Associated minor building works require for the erection of the distribution boards and panels shall be included in the scope of work.
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.
Construction projects highly depends on typical installation details and drawings. Architects and engineers use this kind of information to reduce their work load. Employees particularly technicians and foremen who execute the project uses typical drawings as general guidelines where repeated structure, forms, shapes, operations, loads, etc. come into force.
Vacuum Interrupter (VI) are vacuum sealed-off devices incorporated in Vacuum Circuit Breakers (VCB) to cause interruption of fault currents in medium voltage electrical distribution systems. The contacts of the VI are pressed against each other under normal circuit conditions. In the event of a fault current, the VCB mechanism effects withdrawal of the movable contact from the fixed contact.