Set electrical load calculations in Revit

00:03

When working with electrical designs in Revit, it is important to understand the fundamentals of analyzing electrical loads.

00:10

In this exercise, you specify the electrical load calculation settings before starting an electrical design.

00:17

To begin, on the Systems ribbon, in the Electrical panel, click the dialog box launcher to open the Electrical Settings dialog.

00:26

In the left pane, select Load Calculations to choose one of the Apparent load calculation methods:

00:32

Sum true load and reactive load or Sum apparent load.

00:37

For this example, select Sum true load and reactive load.

00:41

Click Load Classifications to open the Load Classifications dialog.

00:46

Under Load classification types, select Motor.

00:49

Then, expand the Demand factor drop-down and select Motor.

00:54

Note that load classification types are defined by: Name, Abbreviation, Demand factor, and Load class for use with spaces.

01:03

Next to Demand factor, click the More (…) button to open the Demand Factors dialog.

01:08

Expand the Calculation method drop-down to select from three methods that can be used to define a demand factor:

01:15

Constant, By quantity, and By load.

01:19

For this example, select Constant.

01:22

With Constant selected, you can now apply a constant demand factor and add an additional load for the calculated result.

01:29

Note that the Additional load option is available for each calculation method.

01:34

Next, select the By quantity calculation method, and a table appears to define the demand factor for various quantities of items.

01:42

Here, you can specify several quantity ranges for connected objects and apply a different demand factor to each range.

01:49

You can also apply the same demand factor to all objects, depending on how many are connected.

01:55

The Greater Than column specifies the lower limit of a range of objects and always starts with 0.

02:02

The Less Than or Equal To column specifies the upper limit of a range of objects.

02:07

Demand Factor specifies the percentage of full rated load that will exist at any given time for the specified connected objects.

02:15

Under Calculation options, select either Total at one percentage or Incrementally for each range.

02:22

You can then set the quantities and demand factors for each row, and rows can be added or removed.

02:28

Pay attention to the fact that the second column is Less Than or Equal To, whereas the first is Greater Than.

02:34

Finally, select the By load calculation method.

02:38

This method is similar to the By quantity method, but instead of specifying the quantities, you specify the load.

02:45

Here, select Total at one percentage to assign a demand factor based on total load,

02:50

or based on the total number of objects attached to a panel—in which case, total load calculates the entire load at that demand factor.

02:58

You can also select Incrementally for each range

03:01

to assign demand factors that are calculated incrementally for different ranges of loads.

03:06

When you are done changing load calculation settings, click OK in each dialog box to close them.

03:12

You now know how to specify electrical load calculations in Revit.