Saturday, December 16, 2017

Low Voltage Distribution in Revit

A post about the opportunities and limitations for electrical connectors in low voltage devices (families) using Revit for MEP design.

Low voltage circuits connect similar electrical components to form an electrical system. Once created, you can edit circuits to add or remove components, connect a circuit to a panel, add wiring runs, and view circuit and panel properties. Wiring is not necessary, but can be used to show wiring that is exposed or concealed within walls, ceilings, and floors.

A low voltage component can be connected in a circuit if it is...
compatible with the other components in the circuit and if it has an available connector. Using Revit, you can create circuits for two system types:
  • Power systems include lighting and power distribution systems. When circuits are created for a power system, only compatible devices can be connected. All devices in a circuit must specify the same distribution system (voltage and number of poles). The distribution system can be specified by type parameters or instance parameters. When you create a circuit where all the devices have the distribution system specified as instance parameters, Revit displays a Specify Circuit Information dialog where you can specify values for the number of poles and voltage prior to creating the circuit.

    You can add a device to an existing circuit when its distribution system matches that of the existing circuit. When adding a device with the distribution system specified as instance parameters, the distribution system for the device will assume the values of the circuit where it is being added. 
  • Other systems include data, telephone, fire alarm, communications, nurse call systems, security, and control systems. While it is still only possible to connect similar components within a particular system, there are no other checks (voltage or number of poles) for compatibility between the components that make up these systems. It is up to the system designer to maintain consistency of the devices connected in these systems.

Fire Alarm content and fire alarm panel board

Connector must be “power” and not “other” to properly calculate the total load at panel. To properly design a Fire Alarm system, we need report loads to the circuits on the panel.

Fire alarm panel schedule reporting loads utilizing special distribution system at 24v

Notice, when the device is selected we see a VOLTAGE parameter with a load in the project browser.
Fire alarm horn/strobe selected – notice load in properties

A specific distribution system is required for each low voltage system you want to track and develop loads for. The 24 volt fire alarm system example is shown below.


In the family editor, when the connector is selected, the System Type if initial set to Fire Alarm; if using the out-of-the-box Revit content, as shown below.

Here are the other options for System Type...
Selecting Power, rather than Fire Alarm, gives you load options.
Keep in mind, the family is still assigned to the Fire Alarm category, so you still use the Fire Alarm command to place, and control visibility in the project. However, you create a power circuit rather than a fire alarm circuit.

This is how we set up the productivity pack that Cad Technology Center offers. For more information on that, go here: Mechanical Electrical Plumbing Productivity Pack

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