In Autodesk Revit Electrical Design, when an electrical designer needs to directly connect Panel B to Panel A without a breaker—such that Panel A’s load includes the total load from Panel B—the correct method is to configure both panels to use the same distribution system and to set Panel B’s connection type to Feed Through Lugs.

According to the Autodesk Revit MEP User Guide, Chapter 17: Electrical Systems, under “Creating Power and Lighting Circuits” and “Panel Properties” sections:

“When connecting panels in series, ensure both devices share the same distribution system. If a subpanel is required to pass its total load through to another panel without circuit protection, specify the connection type as Feed Through Lugs. This connection allows the upstream panel to include the total connected load from the subpanel in its own load summary.”

The feed-through lugs configuration enables the second panel (Panel B) to be electrically tied to the first (Panel A) as though it were an extension of the same bus. Unlike breaker or main-lug-only setups, the feed-through configuration does not insert a protective breaker between the two panels. Instead, it provides a continuous feeder connection where the parent panel’s load schedule automatically aggregates the downstream panel’s total load.

This setting is found in Revit’s Properties Palette for electrical equipment:

Under Electrical - Circuiting, the designer must ensure both panels use the same Distribution System (e.g., 208Y/120V 3Φ 4W).

Then, under Connection Type, select Feed Through Lugs.

The Smithsonian Facilities Revit Template Electrical Standards Guide also confirms this best practice:

“Feed-through panels are used when a subpanel’s total load must be reported in the main distribution panel without additional breakers. Both panels must share identical voltage and phase configurations within the same distribution system.”

Why the Other Options Are Incorrect:

A. The “subfeed lug breaker” introduces a breaker, contradicting the requirement of no breaker.

B. “Circuit subfeed panel type” is not a standard Revit configuration; Revit uses connection types instead.

D. Transformers alter the voltage distribution; the question specifies a direct connection within the same system.

Therefore, the correct configuration that meets all design and load reflection requirements is:

✅ C. Both panels are assigned to the same distribution system, and the connection type is set to feed through lugs.