Logic Families in Digital Electronics - TTL, CMOS, and ECL

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.

Typical Cable Laying Details For Direct Buried, Low Tension Cables

Most Construction projects requires underground cabling system for its power supply, some times High tension system too. The architects and builders are least bothered about how this cables routed to the premises and equipment. If electrical professionals pointed out the feasibility, the aesthetics of the project would touch to the intended level. Hence, in the planning stage itself the routes and size of the power cable trench to be incorporated in the project design.

Temporary Utilities of Water, Electricity, A/C, Lighting For Construction Site

It will be the Developers responsibility to obtain all necessary approvals from Authorities having jurisdiction for temporary connections to existing infrastructure. Temporary utilities shall be installed in such a manner as not to interfere with permanent construction. The Plot Developer shall provide any temporary holes or sleeves required to install the temporary utilities and shall be responsible to fill the same upon removal of utilities.

Wiring Materials And Installation Methods in Electrical Construction Works

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.

Method of Earthing or Grounding Of MDB, Panel Boards, Lighting And Wiring Installations

Method of Earthing To Main Distribution Board (MDB)

Main earthing bar is to be provided in main distribution room and connected to earth electrode by 2 insulated conductors (minimum 150 mm2) via testing joints. Earthing bars of main distribution boards are to be connected, by insulated earthing conductor, directly to main earthing bar at main distribution room.

Conditions Of Sub-Contract Agreement In Construction

Occasionally Main Contractor of the construction work depends sub-contractor for accomplishing some smaller or part of the project that may require specialized technical know-how and installation methods. In those cases Main contractor selects some sub-contractors who has capacity to achieve the task within the given time frame. Hence both of the parties, ie., Main contractor and Sub-contractor to be signed an agreement which protects both the parties' interest. Here is a sample for Conditions of Sub-contract Agreement in Construction Works.

Guidelines for Installation of Emergency Power Diesel Generating Set

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.

Method of Earthing or Grounding for Diesel Generator Plant

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.

Testing and Commissioning In Electrical Construction Works

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.

Lighting Distribution Boards (LDB) In Electrical Construction Works

Lighting Distribution Boards (LDB) are an integral and essential part of every building project and it must be designed, manufactured and installed all in accordance with the safety standards. In most of the cases it operates a layman wherein others operate dedicated or trained person. This article explains what are the essential standards, parts, frame to be applied for manufacturing and installation of lighting distribution boards in a quality building project.

Construction Shop Drawings

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.

Mechanical Services In MEP Construction

Particular Specification For Mechanical Services describes various general requirements In MEP Construction Work, a contractor to follow when they start executing but not limited to unforeseen work or requirements to accomplish the whole project contract.

Electrical Earthing or Grounding Electrode Design for Building Construction

Earthing or Grounding Electrode for an effective and reliable electrical earthing system requires proper survey and analysis of project location, type of structures installed and electrical / electronic equipment used in the entire system. The design calculation of the earth electrode systems shall be based on the approved earth resistivity data and the system's fault currents and their duration.

Engineering Drawing / Drafting

Drawing means lines, shapes, finishes, sizes and colour combined to construct objects or structures. It will be a cumbersome task when narrating an idea without drawing, if the idea is an object or structure. Engineering is heavily depending on drawings, since, technical drawing has developed a global language named Engineering Drawing, capable to express its objects and structure to everyone without the barrier of human languages. Engineering Drawings conveniently helps to explain and record an idea that can be smoothly conveyed to one person to other or sometimes to machine too.

Refrigeration Plant in MEP Construction

In this sample MEP specification section, Mechanical Refrigeration Plant has been described in detail under construction contract work. Main Highlights of this MEP Specification are: General Requirements, Compressors, Evaporators, Condensers, Condensing Units, Refrigeration Plant Accessories, Pipework, Valves and Ancillaries, Insulation, and Controls.