RA 7920 Provision on Signing of Technical Documents and Drawings
Is it legal for a Professional Electrical Engineer (PEE) to sign and seal plans (drawings) and designs done by others? In legal terms, the answer to that question is NO. …
Effects of Temperature On Cables – Faulty Electrical Wiring
Safety In Design In one project that I got involved with, I came up with several options for cable selection. In all options, the current carrying capacity of the cables …
Calculating Utility Source Impedance
This article will illustrate the basic theory of calculating a utility source impedance from fault data provided by power providers. Utility fault levels are usually expressed in MVA or Amperes …
Circuit Breaker Time-Current Characteristic Curve Made Easy
Circuit breakers time-current characteristic curve could be shaped to allow adjustment of individual circuit breakers for proper coordination between upstream and downstream protective devices. The basic adjustable functions are: Continuous …
Advantages of Per Unit and Percent Calculations
Power System analysis software is very expensive and beyond the reach of small and medium enterprises. The only option, when fault analysis is required, is to perform calculations manually using …
Symmetrical Components – The Beginning
Symmetrical components calculation is a valuable tool in system fault analysis and relay protection. Prior to the advent of computer-aided electrical system modelling software, system analyses were done manually. Today, …