Interconnecting Panels and Transformers

Connecting 208/120 volt panels to 480/277 volt panels requires the use of a transformer.  Once the panels and transformers in the distribution system are all connected, loads from the low voltage panels feed through the transformers to the high voltage panels, giving the ability to compute and tabulate the total connected load in the distribution system.

Connecting panels to one another, or to transformers, is concptually similar to circuiting Devices.  You select the component you want to connect, create the power circuit, then specify the equipment that feeds the selected equipment to complete the connection.

Click here for a brief demonstration video.  The basic steps are:

1. Place Panels using appropriate types

2. Set Panel Name and Distribution System for each panel (LA for 208/120, and HA for 480/277).

3. Place transformer

4. Set Primary (480/277) and Secondary Distribution System (208/120) on transformer.

5. Set the transformer name (shown as Panel Name) to T-LA

6. Tag the equipment (optional)

7. Circuit low voltage (208/120) panel LA to Transformer T-LA - note changes in System Browser showing relationship.

8. Circuit the transformer T-LA to the high voltage (480/277) panel HA.

9. Modify the rating of the circuit on HA feeding T-LA:

 

Note: breaker is rated 125% for continuous load, and is rounded up to next standard breaker size.  Standard breaker sizes are: 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 800, 1000, 1200

10.  Modify the rating of the circuit on HA feeding T-LA:

 

Note different manufacturers provide different standard panel ratings.  Generally, they are 60A, 100A, 125A, 200A, 225A, 400A, 600A, 800A, 1000A, 1200A

Cheers-
Martin Schmid, P.E.
MEP Customer Success Engineer

Comments

[lawn equipment]

Thanks for the basic steps, whew! It's not as simple as i think though.

Luigi Hanway

[Clenbuterol]

But it is fraught with an explosion