commercial electrical load calculation spreadsheet

How to Conduct Commercial Electrical Load Calculations in Canada

When designing a commercial building's electrical distribution system, determining the correct size of the incoming power load is one of the first essential steps. This involves calculating the total electrical demand of all equipment and devices within the building. In this article, we will explore how to conduct commercial electrical load calculations in Canada.

Understanding Demand Factors

To determine the correct size of the incoming power load, it's crucial to understand demand factors. The Canadian Electrical Code (CEC) outlines general rules for electrical loads, including Table 14, which documents demand factors and Watts per square meter for different types of buildings and occupancies. According to Rule 42-006(2), demand factors are applied when determining the size of the main service.

Realistic Demand Factors

Not all businesses use electricity in the same way. For instance, a bakery may require less power than an autobody shop. As electrical engineers, we discuss with our clients whether such usage is realistic and apply demand factors accordingly. Even in cities like Edmonton and Calgary, where temperatures can drop significantly during winter, we take into account the actual usage patterns of businesses.

Calculating Electrical Loads

To calculate electrical loads, we consider various types of equipment and devices within a building, including:

* Welders (Section 42): For light-industrial shops, a group of welders can be calculated at 100% demand. However, for larger groups, we apply the following formula: 100% of the two largest calculated currents plus 25%.

* Electric space heaters (Section 62): For residential buildings, these devices are typically calculated at 50% demand.

Engineering Discretion

In some cases, we can use our engineering discretion to lower demand factors to more realistic values. This is especially true when considering the actual usage patterns of businesses in different regions of Canada.

Conducting commercial electrical load calculations requires a thorough understanding of demand factors and various types of equipment and devices within a building. By following the guidelines outlined in this article, you can ensure that your building's electrical distribution system is properly sized to meet its unique needs. Remember to always consult with experienced electrical engineers to determine the most accurate and realistic demand factors for your specific situation.

Commercial electrical load calculation spreadsheet