International System of Units (SI System)
The International System of Units (abbreviated SI) is the world's most widely used system of units. The system consists of a set of units and prefixes...
Understanding LV Circuit Breaker Fault Ratings
I think this post is going to be helpful to several of our readers. While the IEC low voltage circuit breaker Standard [IEC 60947-2, Low voltage switchgear...
Alternating Current Circuits
Alternating current (a.c.) is the backbone of modern electrical power distribution. In this article I’ll be pulling some of the more important concepts...
IEC 61439 - The Switchgear Standard
The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly...
Thomas Edison
American inventor Thomas Alva Edison was born in Milan, Ohio on February 11, 1847. He was the youngest of seven children and received little formal schooling...
DC Component of Asymmetrical Faults
The image (reproduced from IEC 60909) shows a typical fault in an ac system. From the illustration it can seen that there is an initial dc component ...
Frame Leakage Protection
While not as popular as it once was, frame leakage protection does still have some use in some circumstances. In essence frame leakage is an earth fault...
Closed Doors
"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong...
Railway Electrification Voltages
This post is quick introduction and overview to different railway electrification voltages used in answer to a question sent in via email. While there...
3 Phase Loads
Three phase systems are derived from three separate windings, either connected in delta or star (wye). Each winding can be treated separately, leading...