> For the complete documentation index, see [llms.txt](https://docs.strata.hendersonengineers.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.strata.hendersonengineers.com/workflows/electrical-planning/hierarchy-and-equipment.md).

# Hierarchy and equipment

Build electrical sources, distributions, branches, spaces, and equipment.

Level-by-level detail for the electrical hierarchy: System → Source → Distribution → Branch → Space. See [System Hierarchy](/reference/reference/system-hierarchy.md) for the overview diagram.

> 📸 **Screenshot — Branch detail pane** A selected Branch (panelboard) with the right detail pane showing Power Densities, Special Loads, the Connected Load / Load Density summary, and the Est. Panel Size. This is the fully-configurable level and the best single illustration of the electrical inputs.

***

## Source

The origin point of electrical power for the system — where utility power enters the building's distribution network, or where a backup source (e.g., an ATS) heads a system.

**Equipment types:** Switchboard, Switchgear, Distribution Board, Distribution Panel, Panelboard

**Fields:**

| Field            | Description                                                                                                                                                                                                 |
| ---------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Service Voltage  | Required. Drives Est. Service Size calculation.                                                                                                                                                             |
| Diversity Factor | Engineer-adjustable slider, 0.5–1.0. Reflects estimated proportion of connected load in use simultaneously. Typical range 0.7–0.9 for K-12 schools. Applies to Est. Service Size only — not NEC-prescribed. |

**Summary shown:** Area, Connected Load broken out by category (Lighting / Receptacle / Miscellaneous / Special), Est. Service Size.

**Est. Service Size calculation:** connected load × diversity factor ÷ (voltage × √3 for 3-phase). No 125% continuous-load multiplier at this level — that applies only at the Branch (panelboard) level for conductor sizing.

Downstream equipment (Distribution Boards and any Panelboards connected directly to the Source) appears as a flat list showing each item's connected load and type.

***

## Distribution

Optional intermediate tier between Source and Branch. Skip it on smaller projects where branches connect directly to the source.

**Equipment types:** Distribution Board, Distribution Panel, Subfeed Switchboard

**Fields:**

| Field   | Description                                                                      |
| ------- | -------------------------------------------------------------------------------- |
| Voltage | Required — Est. Size shows a dash until set.                                     |
| Source  | Editable select: create a new source, assign no source, or pick an existing one. |

**Summary shown:** Area, Connected Load by category, Est. Size.

**Est. Size calculation:** connected load ÷ (voltage × √3 for 3-phase). No demand or diversity factor at this level — diversity is applied at Source, demand factor at Branch.

Downstream panelboards appear as a flat list. Only one level of Distribution is supported — nested distribution boards are not shown even if the underlying data model allows them.

***

## Branch (Panelboard)

The fully-configurable level at schematic design. Aggregates space-level load budgets.

**Equipment type:** Panelboard

**Fields:**

| Field              | Description                                                                       |
| ------------------ | --------------------------------------------------------------------------------- |
| Voltage            | Required — drives Est. Panel Size.                                                |
| Distribution Board | Editable select: create new, assign none, or pick an existing distribution board. |

**Summary shown:** Area, Connected Load by category (Special shown as a visually distinct subtotal — it's a discrete load, not density-based), Est. Panel Size.

**Est. Panel Size calculation:**

1. Lighting subtotal × 1.25 (NEC continuous load rule)
2. Receptacle + Miscellaneous + Special at 100%
3. Amps = adjusted total ÷ (voltage × √3 for 3-phase)
4. Rounded up to the next standard size: 100, 125, 150, 200, 225, 400, 600, 800A

There is no engineer-adjustable demand factor at the Branch level — sizing is calculated, not estimated.

***

## Space

Holds the editable load budget inputs and rolls up to its assigned Branch (panelboard) — the electrical equivalent of zone assignment in mechanical.

**Fields:**

| Field         | Unit  | Description                                                                               |
| ------------- | ----- | ----------------------------------------------------------------------------------------- |
| Lighting      | W/ft² | Populated from space type default; editable                                               |
| Receptacle    | W/ft² | Populated from space type default; editable                                               |
| Miscellaneous | W/ft² | Populated from space type default; editable                                               |
| Special       | W     | Open-ended named entries for discrete equipment loads. Description is required per entry. |

**Summary shown:** Area, Connected Load, Load Density (read-only).

* **Connected Load** = (Lighting + Receptacle + Miscellaneous) × Area + Special subtotal
* **Load Density** = (Lighting + Receptacle + Miscellaneous) — density categories only, Special is excluded

A density field that's been changed from its space type default shows a **Modified** badge. Space type and Branch (panelboard) assignment are both editable from the space pane; changing space type refreshes the W/ft² defaults.

There is no demand factor and no mechanical power density on this pane — mechanical loads are handled in the mechanical discipline.

***

## Related

* [Electrical Overview](/workflows/electrical-planning/electrical-planning-overview.md)
* [Electrical Data View](/workflows/electrical-planning/data-view.md)
* [Electrical Equipment Schedule](/reference/exports/electrical-equipment-schedule.md)
* [System Hierarchy](/reference/reference/system-hierarchy.md)