Electrical Drawings Course - Zoning, Legend & Notes

1- Zoning 

Vertical and horizontal zoning may be used if necessary to provide orientation to the field of drawings. Zoning is mandatory for multi-sheet drawings. 

Zones shall be identified by alphabetical (uppercase) and numerical entries in the margin spaces as indicated in Figure 1. 

Zoning allows the drawing to read as a road map, for example you can refer to allocation on drawing as A4 which mean the area found in the intersection between Horizontal Axis A and Vertical Axis 4. 


2- Legend 

The legend is an explanatory table or list of the symbols and abbreviations appearing on a drawing. 

Its main usage is explaining the purpose of each symbol. Using a legend keeps the drawing less congested with information, as it sums up what each symbol and abbreviation means on one page. 

To ensure that a person can correctly read a drawing, a drawing Legend is a key to all the symbols used on this drawing. It is like a dictionary so you can understand the meaning of what the drawing represents. 

Usually, the legend box is placed in the space between the Title Box and the Revision box (see fig.2) but sometimes when there are a large numbers of symbols and abbreviations need to be listed, we can use a separate drawing as the main Legend for the whole project electrical drawings.


To download a list of all electrical symbols that can be used in legend, please click Here

To download a list of all electrical abbreviations that can be used in legend, please click Here 

3- Notes: 
Notes are the information contained on drawings other than views and dimensions needed to understand the drawing completely. 

Notes on a drawing take precedence over specification requirements; hence, notes conflicting with referenced specifications shall not be placed on a drawing unless they are necessary for deviations from certain provisions of the specification. 


Notes location :

The notes with all different types can be located at any one of the following three places( see fig.3): 

Adjacent to the upper left border and to the left of all views. 

Immediately to the left of the revision block. 

Adjacent to the lower left border or below the revision block, space being left for extending the revision block downward. This location should be avoided whenever practical because the space required for revisions cannot be anticipated. 

Electrical Drawings

Numbering of notes: 

General notes are numbered consecutively downward. Note numbers may be identified on the field of the drawing by placing the note number in a pennant-shaped flag (see fig.4) at the general note location and in the field of the drawing, or in the List of Material (Material Specification column), whichever location is more Appropriate. 


Notes types :
There are many types of notes but I will list the famous ones as follows: 

  1. Security classification 
  2. Dimensions notes 
  3. General notes 
  4. Warning note 
  5. Miscellaneous notes 

In the next Topic, I will explain in detail each type of the Notes.

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