Yes, your understanding is correct. Functionally, X2 in your single-phase 480D/240-120 transformer is acting as the neutral point, analogous to XO in a three-phase transformer. It is the center tap of the secondary winding and provides the neutral connection for your 240/120V split-phase output. Labeling: Using X2 on your drawings is perfectly acceptable and likely more appropriate. Here's why: Clarity

Since it is a single-phase transformer, using the standard single-phase designation X2 keeps your drawing consistent with the actual transformer configuration.

Avoiding Confusion

Using XO might cause confusion with those more familiar with three-phase transformers. It might lead someone to incorrectly assume there's a fourth wire involved.

In summary

Yes, functionally X2 is the neutral, and labeling it X2 on your drawing for a single-phase transformer is the correct and preferred approach.

Important Considerations for Installation



Grounding

The X2 terminal

must be properly grounded according to your local electrical codes. This is essential for safety and proper operation of the system. Typically, this connection is made at the service entrance. Polarity

Ensure that you connect L1 and L2 to H1 and H4 correctly. Incorrect polarity can damage the transformer or connected equipment.

Overcurrent Protection

Properly size and install overcurrent protection (circuit breakers or fuses) on both the primary and secondary sides of the transformer.

Wiring Size

Select the correct wire size based on the expected load and applicable codes.

Torque Specification

Use a calibrated torque wrench and tighten connections per manufacturer specification.

Local Codes: Always adhere to all applicable local electrical codes and regulations.It's always a good idea to have a qualified electrician review your installation plan and perform the actual wiring. Flag for review