Getting Revit MEP to Warn About Overloading Breaker

When creating electrical circuits in Revit MEP, it is helpful to utilize Revit’s ability to warn you when you are overloading the circuit.  The issue with utilizing this capability is that if you don’t use the proper process, it won’t work for you.  In essence, you must add electrical items to the circuit one at a time and also modify the proper circuit parameter.  We will walk through the process in this article.

The process is really a 4 step process after you have the electrical equipment or fixtures in place.  For this article, we will look at having several receptacles already placed and creating a circuit from them.  You will see the warning message that appears when you exceed 80% of the breaker’s rating.  The same process is used regardless of the electrical equipment, devices, or light fixtures.

Step 1

Highlight the receptacle.  On the Create Systems panel of the Modify|Electrical Fixtures tab, select the Power command button.  This will create the circuit with only the one receptacle in the circuit at this point.

Step 2

While the circuit is still highlighted (with a blue dashed line around the receptacle), go to the Properties palette.  In the Electrical – Loads section, change the Frame parameter to match the Rating parameter and pick the Apply button.  The Rating parameter is the circuit breaker size.  As you add items to the circuit, Revit will look at the Frame parameter to determine the 80% factor, so you want to make sure that the Frame parameter matches the Rating parameter.  By default, these 2 parameters do not match.

Step 3

With the receptacle’s circuit still highlighted, pick the Edit Circuit command button from the System Tools panel of the Modify|Electrical Fixtures tab.

Select the Add to Circuit button from the Edit Circuit panel of the Edit Circuit tab.

Proceed to select additional electrical items one at a time.  When you have selected enough receptacles to exceed 80% of the breaker, you will get the following warning message.  Using the Remove from Circuit command, remove one of the receptacles to get the circuit load within the allowable limits.

Step 4

Select the Finish Editing Circuit button to complete the circuit.

Notes:

• Selecting items one at a time is important so that Revit can calculate the load of each additional item.
• If you select multiple items prior to creating the circuit, you will NOT be warned about overloading the breaker rating.  It is a common technique of users to highlight several electrical items and then create a circuit.
• At this time, Revit does not automatically size the circuit breaker.

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