Electrical Rooms Dimension

In the initial design steps, Electrical rooms estimated dimensions are requested. Here, we will know how to estimate the dimensions of the following electrical rooms:
  1. Electrical Panel Board Room,
  2. Transformer Room,
  3. Generator Room .


1- Electrical Panel Board Room

After the stage of estimating electrical loads and determining the initial number of electrical panels will be used, the Electrical Panel Board Room dimensions will be estimated by the following steps:


The dimensions of the electric panels are estimated either from previous projects or in accordance with the catalogs of the manufacturers.

to read more: ABB Low Voltage Consumer Units& Distribution Boards


After determining the number of electricity boards and their approximate dimension, the working space should be taken into consideration. According to NEC Cod minimum depth of working space is: 


In a simple way: 


2- Transformer Room

Dimensions of transformer room depend on:
1- The project country and the specifications of the installation according to the electricity company. Room dimensions must be approved from electrical company first.

2 - Is there are any low voltage or medium voltage panels in the transformer room or not?

** If the room include only one transformer we can select the room dimension according to the manufacturer catalog for example:

using the catalog of DRY - Transformers "Elsewedy Egypt" 

Case#1: For indoor substation "1 transformer "

Case#2: For indoor substation "1 transformer with HV switch-gear "

Case#3: For indoor substation "2 or 3 transformer "



3- Generator Room

The dimensions of Generator room can be found Easier, through manufacturer catalogs, for example:

by using Cummins catalog:

to read more:

  • IAEI magazine
  • NEC
  • Ergon energy
About the Author:
Eng. Eman Mohamed 


  1. Eng/Eman , Eng/Ali
    Could you please explain how to determine the initial number of electrical panels will be used?
    Thanks in advance .