AutoCAD MEP Wishes

New Member
Posts: 2
Registered: ‎03-07-2012
Message 1 of 5 (1,761 Views)

Panel to panel via transformer

1761 Views, 4 Replies
03-07-2012 02:45 PM

The connection from panel to panel via transformer does supply the correct breaker size; for example


If I have a High voltage panel “A” (277/480 3 phase) feeding a transformer 45 kva which then feeds a 150 amp panel “B” (120/208 3 phase), when I select panel “B” to be connected to panel “A” with the option of via transformer with different voltage- the breaker size should be to transformer (70/3 phase) but instead it shows the 150a breaker for the sub-panel (150 amp).


The breaker from the Panel "A" is feeding the transformer at a higher voltage then the transformer, reduces the voltage 9120/208) which feeds to the sub-panel "b" ( 150 amp from that point on).

Posts: 1,297
Registered: ‎11-16-2005
Message 2 of 5 (1,756 Views)

Re: Panel to panel via transformer

03-08-2012 04:06 AM in reply to: garzajerry63

Hi... thanks for the note.  I understand the issue here, however, you can of course change the rating in Circuit Manager.


 I've logged this for our team for future consideration.





Martin Schmid, P.E.
Product Manager - Revit MEP
Architecture, Engineering, and Construction
Autodesk, Inc.

New Member
Posts: 2
Registered: ‎03-07-2012
Message 3 of 5 (1,752 Views)

Re: Panel to panel via transformer

03-08-2012 05:45 AM in reply to: martin.schmid

The fix should be easy (in my mind)


1. Update the transformer block to be more like the panel block. The current xfrmr block does not have any electrical function like standard lighting/recept. Someone missed the boat on this one.

2. The transformer block should should have the capability to have electrical connectors (like a recept. / panel)

3. The xfrmr should be in the circuit manager like a std. panel.


The new version of should allow you to select the transfomer (either from the drawings or circuit manager) that will link the two panels together, check for overload and have a one step panel schedule that shows the high to low voltgaes info, which panels are connected and the in / out breaker size need.


Valued Contributor
Posts: 51
Registered: ‎10-02-2008
Message 4 of 5 (1,057 Views)

Re: Panel to panel via transformer

01-10-2013 11:32 AM in reply to: garzajerry63

While your'e at it, perhaps add a way to account for transformer losses.  KW in does not equal KW out, the heat has to come from somewhere.



Valued Contributor
Posts: 51
Registered: ‎10-02-2008
Message 5 of 5 (1,051 Views)

Re: Panel to panel via transformer

01-10-2013 12:20 PM in reply to: garzajerry63

Don't know where the "edit" button is or I would have edited the above post.


Let me also add the need to be able to connect any load through a transformer.  The "connect via transformer" option is only available for panels.  What about a machine that has its own dedicated transformer?  No-can-do.  Not if you want the machine to show it's actual  voltage.


Our workaround is to create a dummy panel on a no printing layer.  Lets say 480v panel MDP feeds a 208v power connection for a widget welder via a transformer TX1.  We create a hidden 208 panel "WW" with 1 circuit and connect the welder to it.  We then cunnect the dummy panel WW to MDP via a transformer.  We label the circuit in panel MDP "widget welder" and size it to suit the primary of the transformer.


This works, but in a big factory we end p with a couple dozen phantom panels.  This adds a lot of clutter to the dropdowns and in circuit manager.

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