From the monthly archives: April 2012

We are pleased to present below all posts archived in 'April 2012'. If you still can't find what you are looking for, try using the search box.

Arc Flash Calculations

By Steven McFadyen on 3/22/2012 6:14 AM

Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash. To protect people a risk analysis on the ar... read more..


Windows Live Writer and myElectrical

By Steven McFadyen on 3/15/2012 7:27 AM

When making adding a Note to our site we have a great online WYSIWYG editor and things are pretty simple.  However, if you prefer you can write, manage and publish your posts using any external ... read more..


Tech Topics/Application Notes - Siemens

By Steven McFadyen on 3/13/2012 6:21 AM

There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens US site, so many of he note are IEEE/ANSI ... read more..


Hazardous Areas – IEC and NEC/CEC Comparison

By Steven McFadyen on 3/9/2012 11:39 AM

Depending where in the world you work, you are likely following one of two standards

  • International Electrotechnical Commissio... read more..


IEC 61439 Verification Methods

By Steven McFadyen on 3/3/2012 3:33 PM

The (relatively new) switchgear and control gear standard, IEC 61439 'Low-voltage switchgear and controlgear assemblies' has three methods which can be used to verify the characteristics of an assemb... read more..


Lead Acid Batteries

By Steven McFadyen on 3/3/2012 12:57 PM

Lead acid batteries are cost effect and reliable, making them suitable for many applications.This note examines topics of interest associated with the use of these batteriesLead acid batteries are co... read more..


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Low Voltage Fault Tables

The following tables provide quick order of magnitude fault levels for a a range of typical low voltage situations.

UPS Battery Sizing

Various techniques exist to enable the correct selection of batteries for UPS applications.  The procedure described below is one of the more common. ...

1,000 kV UHV First for China

At the beginning of the year China put the world's first 1,000 kV UHV transmission system into operation. Transmitting power at over a million volts is...

The ac resistance of conductors

In a previous article I looked at the dc resistance of conductors and in this article we turn our attention to ac resistance. If you have not read the...

Maximum Demand for Buildings

Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much...

Gas Insulated or Air Insulated Switchgear

Various arguments exist around SF6 Gas Insulated (GIS) and Air Insulated (AIS) medium voltage switchgear. Recently we had to change a GIS design to AI...

Motor Insulation

Insulation on a motor prevents interconnection of windings and the winding to earth.  When looking at motors, it is important to understand how the insulation...

Windows Live Writer and myElectrical

When making adding a Note to our site we have a great online WYSIWYG editor and things are pretty simple.  However, if you prefer you can write, manage...

IEC Reference Designations

The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment.   Depending on country...

Cables for MV Power Distribution - Earthed versus Unearthed Systems

Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...

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