Home battery, backup, and island mode
Condui is the only drawing tool that represents a complex backup or off-grid supply as one coherent, editable topology in the same electrical project. Draw the grid input, hybrid inverter, home battery, solar panels, backup output, protection, and source transfer switch as real parts of the supply, instead of pasting disconnected text or an image over the one-wire diagram afterwards.
Not every home battery needs to power the complete home during a grid outage. The inverter's backup output can supply one protected circuit, a separate backup panel, or a defined part of the main panel. Choose which essential loads remain powered, such as lighting, refrigeration, networking, heating, or one socket. The other circuits remain visibly grid-fed, with a clear split between grid and backup.
A single-phase inverter can supply one selected phase. For a supported coordinated three-phase arrangement, Condui can show three physical single-phase units, such as a possible Victron MultiPlus-II configuration distributed across L1, L2, and L3. Brand, model, and power stay shared while serial numbers and placements can differ per unit.
With whole-home backup, the complete installation sits downstream of the source selection and the load side can change between grid and backup power. Draw a source transfer switch with separate grid input, backup input, and output to the panel. A fully off-grid installation instead operates as a local island and never runs in parallel with the distribution grid. Condui keeps these sources and supply paths visibly separate.
An ATS is an automatic transfer switch. Condui's current source transfer switch models a manual, mechanically interlocked break-before-make source selection: the first source disconnects before the second connects. Synergrid C10/11 uses this principle for transitions between on-grid and off-grid modes when an installation can connect to the distribution grid. C10/26 concerns homologation of the generating unit or inverter, not blanket approval of a one-wire diagram or arbitrary ATS. In AREI terminology, a source that takes over during a grid outage for reasons other than personal safety is a replacement source associated with a critical installation. “Safety supply” is therefore not a generic name for every home-battery backup. Record the real equipment and always follow the approved design from the manufacturer, installer, and grid operator.
A suitable hybrid solar inverter, such as a Fronius GEN24 Plus, can also be drawn as part of the supply. Solar panels and the battery connect on the DC side, while the grid connection and separate backup output retain their own place in the one-wire diagram. This keeps the source of each supplied part visible.
The physical supply components can also be represented in the panel view. Place the source transfer switch, protection, and relevant supply equipment in the main panel, a supply panel, or a separate backup panel, without turning the panel view into a second electrical schematic.
Condui records the selected topology, but does not decide whether specific devices may work together or how protection, earthing, and changeover must be implemented. Always check the manufacturer's documentation and the actual installation design.
### Can I draw a source transfer switch in the one-wire diagram? Yes. Place the source transfer switch in the supply and represent its grid input, backup input, and output to the panel separately. ### Can one Victron MultiPlus-II supply only one socket? Yes. Its separate backup output can supply one limited protected emergency circuit, such as a single socket, without drawing the complete main bus as a backup supply. ### Can only part of my distribution panel run from the home battery? Yes. Condui can split the main panel into a grid-fed and backup-fed bus section. Essential circuits remain on the backup output while the other circuits are supplied only by the grid. ### Is a source transfer switch the same as an ATS? No. ATS means automatic transfer switch. The current Condui arrangement uses a manual break-before-make changeover. Automatic transfer has its own equipment, design, and inspection requirements and must not be treated as C10/11-compliant based only on the symbol in the drawing. ### Can Condui draw three single-phase inverters as a three-phase group? Yes, when the manufacturer supports the units as one coordinated group. Condui can show the three physical units across L1, L2, and L3. Three independent inverters do not automatically form a valid three-phase backup installation.