AutoCAD MEP Implementation - Part Three

November 14th, 2011

In the first two parts of this series, we started a new template and set HVAC and piping settings and saved our template.  Now let's open that template again and set our electrical settings. 

We need to change our Electrical Workspace.    This will change our ribbon to include electrical tools in the Build panel of the Home tab of the ribbon, electrical annotation tools, and more. 

The electrical portion of AutoCAD® MEP uses what are called devices for their parts.  There's a piece of lingo you can keep in mind. 

AutoCAD MEP electrical covers electrical devices and equipment as well as wiring.  Cable trays and conduit are also part of this.  So you might imagine there is more to setup in your implementation in electrical than there was in HVAC or piping. 

There are five styles in the Electrical Workspace.  Let's start with the Electrical System Definitions.  Remember that as we mentioned in the previous articles to this series, AutoCAD MEP is very style-based.

There are plenty of Electrical System Definitions that come ready out-of-the-box.  You can edit, add, or delete styles.  We're only going to look at the Design Rules tab.  The other tabs are really the same that we've covered in previous articles. 

The Design Rules tab includes layer key information.  It is a little more in-depth than some of our basic Design Rules tab layer information.  It shows us a System Group and System Type.  We might have a System Group of Power & Lighting which would allow us to connect systems that were otherwise in different groups.  But in our world of electrical design we know that it would be common to place circuits for 120v power and lighting. 

Load categories help us set loads by demand factor for various types of equipment.  Create your own, rename, or modify the Load Category Definitions shown here out-of-the-box. 

Specify a constant value demand factor or one that varies depending on quantity. 

Electrical panel  styles do not show up until a panel is placed in the drawing.  Standard would be the only style you would see.  I have placed two panels in this drawing.  The Design Rules tab does not list layer key styles as many of the other styles do.  For Panel Styles, Design Rules indicated how wire will look in plan view when it's attached to the panel.  Trace Geometry is the default and simply means that the line will be trimmed to the outside of the block that represents the panel in top view. 

The Views tab shows the blocks used while the Connectors tab shows connection data information associated with the block shown for the panel. 

Device styles also shows Wire Cleanup under the Design Rules tab.  In addition it shows a type of device.  Like panel styles, these only show when they have been inserted in the drawing.  Layer key is indicated in this tab.  The remaining tabs are similar. 

While we are not going to cover how to set loads and all the places you can do so to calculate loads, voltages, or circuit numbers, you can see an example of the types of information that should be set in the design phase. 

If you find particular devices or panel styles that you would likely use, I would suggest placing these on a tool palette and setting this information one time with the source drawing.  One of the cardinal rules of CAD that I learned early on was "never draw anything twice."  The same goes for repeating any procedure in AutoCAD MEP. 



I will give you a hint that if you are having trouble finding devices—it’s not terribly intuitive.  You must click on Properties in the symbol shown for style.  That will bring up another dialog box with various devices.  That's my free hint for you.

Wire styles come in 1-, 2-, or 3-pole.  The specifications come fairly well preset with some extra information you can provide such as isolated ground or a choice between specifying to match hot or specify neutral. 

More of the wire style is the appearance in plan view.  Wire is not visible in any 3D view as conduit and cable trays are. The default annotation settings include hash marks on the wire and home run arrows.  If you don't like any annotation on your wire, uncheck the box Display on wire segment.  If you don't want these on home run, then uncheck the box Display on home run.  Your home run arrow is a closed filled arrow by default.  You can choose a different arrow, none at all, or display an arrow for each circuit.  You also can specify how wire crosses over other wire or how it shows to connect. 

I'll give you more tips on some of this in the last part of this series with tips and tricks.  

Preferences on the Manage tab covers Electrical, Conduit, and Cable Trays.  Some of the preferences are the same as in duct.  We'll look at the differences. 



Electrical preferences has three tabs to offer.  Voltage Definitions is the first and generally isn't one I see users change.  You can edit any of the minimum or maximum settings by clicking in the field to change.  Adding new is the button at the bottom with the * and the button with the x will delete one. 

Circuiting handles how circuits are added in Circuit Manager.  Circuit Manager is a tool to control the circuits in a panel.  You can have a prefix in the name such as LPT so the first panel would be LPT1.  You can number them in order sequentially or by poles increasing number or grouping.  You can also check or display overloads when a load reaches any percentage of the circuit rating you enter or an ambient temperature of the wire. 

Electrical Project Database is to enter the path of a file AutoCAD MEP uses to circuit across multiple drawings (such as xrefs). 

Conduit Layout Preferences are very similar to duct preferences in the routing tab.  All of these can be set on the fly as well.   The Annotations tab gives you the options to have labels of systems or arrows and parts gives us the ability to select parts that will be automatically inserted when we change elevation or direction.  Conduit works very much like piping.  Connections really only lists the connection style, which for conduit is conduit.  Go figure. 

Cable Tray Layout Preferences has the same routing and parts as conduit.  The annotation is visual as to how the pattern appears.  You have the label and flow arrows also found in other preferences. 

The Connections tab allows you to set how you want to show connections to other cable trays. 

Once you've gone through these settings, you can save your template again.  Keep in mind as you design, if you see results that you would like to change you can always change your template if these are standards that you would like to have available with every new drawing you do. 

The final part of the AutoCAD MEP Implementation series will be a wrap up of all we covered in the series with real-life examples and recommendations to help you implement this powerful program.

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About the Authors

Beth Powell

Beth owns CAD Fuel Design in Roanoke, Virginia.  She does contract CAD work for the petroleum industry.  She provides training and support for AutoCAD, AutoCAD Architecture , AutoCAD MEP software and assists firms with CAD Standards.  She is a beta tester and usability tester.  She has been an instructor at AU for 3 years as well as a veteran CAD Camp instructor.  Beth served on the AUGI Board of Directors, has written for AUGI publications and served as an instructor in the AUGI Training Program (ATP).  Her blog is http://bethscadblog.blogspot.com/.

 

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