Energy and Power
Which type of residual current device (RCD) to use and when?
We know how (very) important the total earth loop impedance Zs is in the reduction of shock risk. However, in TT systems where the mass of earth is part of the fault path, the maximum values of Zs given in… Read more
Apr 09, 2014 | By Edvard Csanyi
Energy and Power
Erection of earthing arrangements (TNC, TN-S, TNC-S, TT)
The earthing arrangements (TNC, TN-S, TNC-S, TT) of low voltage networks is largely determined by the Low Voltage Supplies. However, if the incoming supplies are at 11kV and the transformers are in the ownership of the user, the LV supplies… Read more
Apr 07, 2014 | By Edvard Csanyi
Energy and Power
Electromagnetic stresses on a busbar system and methods of reducing
When a conductor carries a current it creates a magnetic field which interacts with any other magnetic field present to produce a force. When the currents flowing in two adjacent conductors are in the same direction the force is one… Read more
Apr 02, 2014 | By Edvard Csanyi
Energy and Power
Electrical Design Project of a Three Bed Room House (Part 2)
Continued from 1st part: Electrical Design Project of a Three Bed Room House (Part 1) All new domestic dwellings, including conversions, must either have: A fire detection and fire alarm system in accordance with the relevant recommendations of British Standard… Read more
Mar 31, 2014 | By Sufi Shah Hamid Jalali
Energy and Power
Enclosure protection against ingress of solid objects and liquids
As you already probably know, IP stands for Ingress Protection. International Electrotechnical Commission – IEC 60529 “Degrees of protection provided by enclosures (IP Code).”. NEMA offers a similar rating system. In order to protect live parts of equipment being contacted… Read more
Mar 26, 2014 | By Edvard Csanyi
Cables
Underfloor cable systems explained in details
It should be understood that the generic term ‘underfloor’ applies to products designed for such use but which may well be used in other environments where the protection is appropriate. Ducts and risers, and within suspended ceilings are typical spaces… Read more
Mar 24, 2014 | By Edvard Csanyi
Energy and Power
Electrical Design Project of a Three Bed Room House (1)
Electrical design is not an easy task. It requires a lot of expertise. Detailed study is needed prior to installation work. The engineer must consider quality and any specific requirements together with price. Different options are to be examined. Choice… Read more
Mar 21, 2014 | By Sufi Shah Hamid Jalali
Energy and Power
Electrical Thumb Rules You MUST Follow (8)
Accuracy Class of Metering CT Accuracy Class Letter of CT Accuracy Class of Protection CT Continued from part 7: Electrical Thumb Rules You MUST Follow (Part 7) Metering Class CT Class Applications 0.1 To 0.2 Precision measurements 0.5 High grade… Read more
Mar 10, 2014 | By Jignesh Parmar
Energy and Power
The Risk Of Deadly Lightning Current and Few Things You Should Know
Lightning currents are load-independent currents, i.e. a lightning discharge can be considered an almost ideal current source. If a load-independent active electric current flows through conductive components, the amplitude of the current, and the impedance of the conductive component the current flows… Read more
Mar 05, 2014 | By Edvard Csanyi
Energy and Power
Total Losses in Power Distribution and Transmission Lines (2)
Continued from first part: Total Losses in Power Distribution & Transmission Lines (1) There are two types of transmission and distribution losses: Technical losses (explained in previous part) Non-technical losses (commercial losses) Non-technical losses are at 16.6%, and related to… Read more
Mar 03, 2014 | By Jignesh Parmar
Cables
Practices for grounding and bonding of cable trays
Cable tray may be used as the Equipment Grounding Conductor (EGC) in any installation where qualified persons will service the installed cable tray system. There is no restriction as to where the cable tray system is installed. The metal in… Read more
Feb 26, 2014 | By Edvard Csanyi
Energy and Power
Effect of utility-induced surges in a steel mill with variable speed drives
A steel mill with variable speed drives (VSDs) had problems of frequent tripping of the VSDs with the indication overvoltage in AC line. Each tripping caused severe production disruption and resulted in considerable monetary loss due to lost production. Steady-state… Read more
Feb 12, 2014 | By Edvard Csanyi
Electrical Lectures
What is the short-circuit switching (making / breaking) capacity?
The switching capacity is the r.m.s value of a current at a given power factor cos φ as well as a given rated voltage at which a switchgear or a fuse can still shut-off under specified conditions in an operationally… Read more
Feb 10, 2014 | By Edvard Csanyi
Energy and Power
Electrical Preventive Maintenance of Air Circuit Breakers
Remove and clean interphase barriers. Clean all insulating materials with vacuum and/or clean lint free rags. If it is necessary to use cleaning solvents, use only solvents recommended by the manufacturer. Inspect for (early) signs of corona, tracking, arcing, or… Read more
Feb 07, 2014 | By Edvard Csanyi
Energy and Power
Purposes and Examples of Safety Interlocking Devices
Most switchboards and motor control centres are fitted with a variety of electrical and mechanical safety interlocking devices. Their purposes are to protect against for example: Withdrawing the switching device while it is carrying load or fault current. Prevent the switching… Read more
Feb 05, 2014 | By Edvard Csanyi
