The supply frame
Understand what the one-wire supply frame represents, when it appears, and how to read one or two supply rails.
The Supply frame on the one-wire diagram groups the devices and connections that deliver electrical energy to a distribution panel. It is an overview of the supply assembly, not another physical panel.
That distinction matters. The ordinary panel frame shows what is downstream of the supply, including protections, circuits, and endpoints. The supply frame shows what is upstream of that panel's rails, including the grid connection, earthing, inverters, battery and PV branches, supply protections, and a source transfer switch.
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Not a separate distribution panel
The supply frame has no cabinet, panel grid, or situation-plan location of its own. Devices inside it can still be real project items with their own properties and placements. The bottom of the frame identifies the real panel supplied by the assembly.
When does it appear?
Condui automatically detaches the supply frame from a main panel when both parts contain enough information to be clearer on their own:
- the main panel contains at least one protection on its main rail;
- the supply contains a more complex assembly, such as an inverter, conversion device, or source transfer switch;
- it is the supply of a main panel, not an ordinary secondary panel behind a protected feeder circuit.
A simple grid supply stays inside the panel frame. A complex supply can also remain there initially while the panel has no main-rail protection. When Condui separates the supply, only its presentation changes. No panel is added and the electrical relationship stays the same.
What is shown in the supply frame?
| Part | Meaning |
|---|---|
| Source | The grid connection or another source where the supply path begins. |
| Supply wire | The continuous AC path towards the supplied panel. |
| Supply devices | Supply protections, meters, inverters, and a source transfer switch. |
| DC branches | Batteries and solar panels connected to the DC side of an inverter, optionally through a DC busbar. |
| Backup output | The separate AC output of a suitable inverter. |
| Earthing | The incoming earthing path and devices such as the earthing separator. |
| Output to the panel | The handoff from the supply assembly to the named main panel. |
The lines show more than drawing order. They also preserve electrical domain, source role, and the phases allowed to continue towards the panel. A grid path, DC path, and backup path can therefore coexist in one frame without suggesting that they form one continuous wire.
A DC rail is a distribution point on the DC side of a device, almost always an inverter. Multiple DC branches can leave the same rail.
One rail
In the simplest organization, the supplied panel has one rail or bus section. Every protection and circuit on its main rail then receives the same panel supply.
The supply before that single bus can still contain several parts. An inverter can have a grid input, DC sources, and backup capability. Until the panel is divided into separate grid and backup sections, the selected supply path ends as one handoff to the panel.
With AC connection > Separate grid and backup connections, that single panel can sit entirely downstream of the inverter load output, without an external transfer switch. The grid input and load output have separate wires where you can place protections. This applies both in the supply frame and inside an empty main-panel frame. See Supply the complete panel through the inverter for the steps.
Two rails: grid and backup
A main panel can be divided into two independently supplied rail or bus sections:
| Rail section | Supply path | Typical contents |
|---|---|---|
| Grid | Direct grid supply | Circuits that operate only from the grid. |
| Backup | Inverter backup output, directly or through a source transfer switch | Selected circuits connected to the available backup path. |
The supply frame then shows two thick rails, each with its own feed marker. The right grid rail and left backup rail are two sections of the same supplied panel. They do not represent two distribution panels, but indicate separate supply paths.
The split determines which rail section owns each protection or top-level circuit. A feed marker on the main rail marks where the following objects change to the selected source. In Properties, Feed organization reports whether the panel uses one feed or a split grid and backup feed.
Grid + backup
With Grid + backup, the grid rail remains connected directly to the grid. The backup rail has its own path from the inverter's backup output. There is no central source transfer switch before both sections.
Grid + switched backup
With Grid + switched backup, a source transfer switch is part of the supply assembly. The supply-frame lines separately show the grid input, backup input, and switched output. Only the rail section connected to that output follows the switched path.
Phases on each supply path
The two rails do not need to receive the same phases. A three-phase grid rail can carry L1, L2, L3, and N, while a single-phase backup output supplies only L1 + N.
Condui derives phase information from the selected inverter phases, the supply-assembly connections, and the handoff to the rail section. A backup path with fewer phases therefore stays limited as it continues through protections, circuits, or secondary panels. Phase labels near the supply make such a transition visible on the one-wire diagram.
A phase label describes the modeled connection. It does not confirm that an inverter, source transfer switch, or protection is technically suitable for the real installation.
Relationship to other views
The supply frame belongs to the one-wire diagram and can also appear separately in schematic output. The panel-grid view remains based on the real distribution panel and its modules. A change to a rail section or supply relationship can therefore affect the supply frame, panel frame, phase labels, validation, and PDF together.
To build one of these arrangements, follow Create backup and off-grid supplies. Use this page as the reference for reading the resulting view.