Eight common mistakes in reading and creating single line and wiring diagrams

Introduction

As I wrote in one of my previous articles, called How to read single line and wiring diagrams, single line diagrams are simplified and digest picture of whole switchboard, showing only major power equipment and connections to other switchboards. Wiring diagrams are used to show control, measurement and signalization principle of operation inside switchboard.

In order to create consistent and technically correct single line or wiring diagram, more than basic knowledge about engineering field in question is required. Besides electrical installation and equipment, design engineer should be familiar with electrical symbols and software package for drawing.

However, today in practice, these two activities are usually done by same person, although in some companies division still exist, and whole process of diagram creation is done by at least two employees.

Practically the same, except maybe necessity for drawing software, stands for diagram reading.

Again, understanding of graphical presentation on one side, and ability to check diagram compatibility with calculations and standards on the other side, are two different things.

Within this article, full engineering approach to single line and wiring diagrams creation and reading will be presented. That means both, design and graphical presentation.

As already started within above mentioned previous article, some most important and most often mistakes during this process will be described. Of course, the goal is to avoid these mistakes whenever is possible, and create correct and usable single line or wiring diagram.

Contents:

Description and examples of typical mistakes:

1. Lack of design tags
2. Inconsistency of design tags
3. Lack of most important textual and numerical data
4. Incorrect graphical representation
5. Lack of connections to other switchboards and devices
6. Incorrect wiring
7. Lack of cross references
8. Lack of comments and clarifications