# AC-03 — AC Power Architecture

**Project:** Open Solar Trailer  
**Revision:** A — 17 September 2026  
**Status:** Design review only — not a construction or cabling release

## Design basis

Continue the current project architecture: one Victron MultiPlus-II 48/5000/70-95 **120 V model**, supplied by the common DC buses on [DC-02](https://open-solar-trailer.pages.dev/electrical.html#dc-02). The baseline AC loads are one RV outlet and two ordinary charging/camp circuits. Optional shore input remains outside the baseline build. These selections match the current Victron revision of the v06 priced planning BOM.

This sheet proposes the connection functions and circuit allocation. Breaker ratings below are planning selections, not a completed protection study. Exact equipment, conductor sizes, terminal arrangements, enclosures, and installation requirements need qualified review before energizing.

The companion [PG-04](https://open-solar-trailer.pages.dev/electrical.html#pg-04) documents protective bonding, source-neutral behavior and the unresolved DC/PV ground-fault arrangement. It does not add a downstream neutral-to-PE bond or finalize protection hardware.

## A. Power paths

In this diagram, an AC arrow represents a circuit containing **L (hot), N (neutral), and PE (protective earth)**. It is not one conductor. PE continuity is maintained separately from switching, overcurrent, and leakage-sensing functions. Dashed arrows identify optional shore equipment. The bidirectional DC connection is the same connection shown on DC-02, not another inverter.

```mermaid
flowchart TB
    DC["DC-02: COMMON DC BUSES<br/>Protected inverter branch<br/>48 V nominal battery system"]
    INV["INV-1: INVERTER / CHARGER<br/>MultiPlus-II 48/5000/70-95<br/>120 V model — one unit"]

    SHORE["OPTIONAL SHORE SOURCE<br/>External 120 V AC only"]
    INLET["OPTIONAL SHORE INLET<br/>30 A nominal inlet target"]
    QIN["Q-IN: OPTIONAL INPUT PROTECTION<br/>Overcurrent protection and disconnection<br/>Matched to source and inlet"]

    SAFETY["AC-OUT-1 SAFETY ASSEMBLY<br/>Q-OUT: 30 A main protection / disconnect proposed<br/>GF-OUT: UL 943 personnel GFCI protection<br/>May be combined equipment"]
    PANEL["PANEL-1: 120 V DISTRIBUTION<br/>AC-L: hot distribution<br/>AC-N: isolated neutral bar<br/>AC-PE: equipment-ground bar"]

    QRV["Q-RV: RV BRANCH<br/>30 A proposed"]
    RV["RV OUTLET<br/>TT-30R<br/>120 V only"]
    QMOB["Q-MOB: MOBILITY BRANCH<br/>20 A proposed"]
    MOB["ACCESSIBILITY CHARGING OUTLET<br/>Vehicle-matched charger<br/>Dedicated branch; manually prioritized"]
    QCAMP["Q-CAMP: CAMP BRANCH<br/>20 A proposed"]
    CAMP["CAMP OUTLET<br/>E-bike chargers, compatible AC lighting<br/>and other selected small loads"]

    DC <-->|"DC power: invert / charge"| INV
    SHORE -.-> INLET
    INLET -.-> QIN
    QIN -.->|"AC-in"| INV
    INV -->|"AC-out-1 only"| SAFETY
    SAFETY --> PANEL
    PANEL --> QRV
    QRV --> RV
    PANEL --> QMOB
    QMOB --> MOB
    PANEL --> QCAMP
    QCAMP --> CAMP
```

**AC-out-2 is unused.** In normal operation that output is unavailable on battery-only power, so it is not the source for our mobility or camp circuits. AC-out-1 is the intended inverter-backed output. [S1]

The output safety block includes both overcurrent/disconnect and personnel ground-fault functions. Victron's installation instructions specify UL 943-compliant residual-current protection and overcurrent protection in the output path. A generic leakage device is not automatically an equivalent substitute. Final part selection and coordination with the BOM's GFCI receptacles remain open. [S2]

## B. Proposed panel schedule

All branches share the same source; their ratings do not add to available output.

| ID | Function | Proposed rating | Status |
|---|---|---:|---|
| Q-OUT / GF-OUT | Main output overcurrent protection, disconnection and personnel GFCI function | 30 A overcurrent rating; leakage device selection pending | Baseline; arrangement requires review |
| Q-RV | RV TT-30R outlet | 30 A | Baseline |
| Q-MOB | Dedicated accessibility-charger outlet | 20 A | Baseline; verify actual charger input |
| Q-CAMP | E-bike charging and selected camp loads | 20 A | Baseline |
| Q-IN | Shore-input overcurrent protection/disconnect | No more than inlet, feeder and source permit; 30 A design target | Optional |
| AC energy meter | Measure total energy supplied to the distribution panel | Compatible with selected feeder | Baseline monitoring; meter wiring not shown |

TT-30R is a 30 A, 125 V-rated receptacle for a nominal 120 V circuit; it is not a 240 V outlet. [S6]

Dedicated mobility wiring does **not** provide automatic load shedding or guarantee uninterrupted charging. Priority means manually stopping discretionary loads before the battery reserve or shared power limit is reached. A common GFCI trip would interrupt all three branches in this arrangement. Protection selectivity and event requirements are review items; protection must not be bypassed to keep a load running.

Optional 12 V sign/lighting/fan circuits remain on DC-02 through their protected converter. They are not duplicated here. AC lighting, when used instead, is included in Q-CAMP's shared load budget.

## C. Hot, neutral and protective-earth connections

These are functional connections, not terminal-position or wire-size instructions. Physical left/right terminal positions must come from the exact equipment manual.

| Connection | Proposed path |
|---|---|
| INV-1 AC-out-1 **L** | Through Q-OUT/GF-OUT as required by the selected assembly, to AC-L, then each branch breaker and its receptacle hot terminal. |
| INV-1 AC-out-1 **N** | Through GF-OUT's specified neutral sensing/switching path to the isolated AC-N bar, then the correct neutral path for each branch. Do not create a neutral bypass around a GFCI. |
| INV-1 **PE / chassis ground** | To the protective-earth network, AC-PE bar, trailer chassis bonding point, panel enclosure and receptacle grounds. No normal load switching or fusing is placed in PE. |
| Optional shore **L** | Inlet to Q-IN to INV-1 AC-in L. Never to AC-out-1 or an output receptacle. |
| Optional shore **N** | Inlet to INV-1 AC-in N through any coordinated neutral switching in the selected inlet assembly; no independently fused neutral. Do not jumper inlet neutral directly to the output neutral bar around the inverter. |
| Optional shore **PE** | Continuous protective-earth connection to the onboard PE/chassis network; not through a relay that opens the protective conductor. |

This source-transfer and PE layout follows the MultiPlus's ground-relay/mobile-installation arrangement; terminal-level implementation remains subject to manufacturer and installer review. [S2]

**AC-N is not DC-02's N1.** AC-N is the AC neutral. N1 is the DC system-negative bus. No direct connection between those two is specified here. DC bonding and the complete chassis/PV grounding plan belong on the later protection-and-bonding sheet.

Use a panel intended for the chosen single-source 120 V arrangement. Do not improvise bus jumpers in a 120/240 V panel unless that use is supported by its listing and manufacturer instructions.

## D. Neutral-to-ground bond behavior

For the standard single-inverter arrangement, retain and verify the intended internal ground-relay operation; do not add a permanent neutral-ground bond to the downstream distribution panel. The MultiPlus bonds output neutral to its chassis during standalone inverter operation and opens that relay before accepting an external AC supply. [S2]

| Operating condition | Neutral-ground arrangement to verify |
|---|---|
| Battery/solar operation; no accepted external AC | Internal inverter ground relay provides the source bond. Downstream AC-N remains isolated from the trailer enclosure and AC-PE. |
| Accepted shore supply | Internal ground relay opens; the external supply must provide the appropriate source grounding/bonding arrangement. No extra panel neutral-ground bond is added. |
| Any mode | Protective-earth continuity and chassis bonding remain intact. Test ground-fault protection in each permitted source mode before service. |

Do not assume a floating-neutral generator is interchangeable with a verified shore supply. A future generator connection requires its own source/transfer/bonding review. This sheet does not specify an earth electrode or claim that a ground rod replaces equipment bonding.

## E. Shared power limit

The manufacturer's datasheet rates this 48/5000 **120 V** inverter at **4,000 W at 25°C** and **3,700 W at 40°C**. “5000” is its VA class, not a 5,000 W continuous rating. [S3]

For our proposed 30 A output main:

- 120 V x 30 A = **3.60 kVA shared nominal distribution rating**, approximately 3.60 kW only at unity power factor. It is not a guaranteed sustained-load allowance.
- For an ordinary 80%-applied breaker/assembly, a wholly continuous load uses at most **24 A**, or **2.88 kVA** at 120 V. A 20 A branch similarly provides a **16 A** continuous-load planning limit. Mixed continuous/noncontinuous loads require the appropriate sizing calculation. [S5]
- Operating capacity is limited by the most restrictive of the inverter's W/VA and thermal limits, battery capability, feeder protection, individual branches, connected equipment and available stored energy.

**30 A RV + 20 A mobility + 20 A camp does not mean 70 A available.** The branch arrangement allows useful connection choices; simultaneous loads must fit the shared limit.

## F. Optional shore charging

Shore power enters **AC-in**. Accepted power can supply AC-out-1 while the charger charges the battery through the same protected DC connection shown on DC-02. [S4]

Set the AC input-current limit to the permitted external source/cord/inlet rating, not the inverter's larger internal transfer rating. Charger settings must also respect the bank's combined limits when solar charging is active. PowerControl manages charging against the input limit; PowerAssist can supplement an external supply with battery energy, but does not change the selected output-main or branch ratings. [S1]

“Charger only” is not an output-isolation mode: accepted shore power can still pass through to AC-out-1. [S4] Baseline construction leaves the optional inlet absent and AC-in unconnected/protected from access. Never feed an output receptacle from another power source, connect output back to input, or use a male-to-male power cord.

## G. Items still to close

1. Exact 120 V panel, breaker and personnel-GFCI hardware, including whole-output versus coordinated downstream protection and costs.
2. Wire sizes, lengths, ampacity/temperature adjustments, terminal compatibility and weatherproof in-use equipment suitable for event conditions.
3. Actual mobility charger and simultaneous RV/camp load measurements.
4. Configuration, transfer/bonding, polarity, ground-fault trip tests and protective-earth continuity checks in every enabled mode.
5. Separate full protection-and-bonding sheet and a safe all-source shutdown/service procedure. Opening the AC main isolates downstream loads only; it does not make all DC/PV or inverter terminals safe.

These are not already resolved by the BOM's two outdoor GFCI-receptacle allowances. Do not treat this architecture as a priced construction specification or as proof of regulatory compliance.

## Sources

Project baseline: **Open_Solar_Trailer_Final_Grant_BOM_v06.xlsx**, Victron revision dated 17 September 2026 — inverter selection, RV/camp outlets, AC metering and optional shore input. This architecture does not recheck or revise prices.

Manufacturer material checked 17 September 2026. The connection allocation, 30 A output-main target, dedicated mobility branch and common output-GFCI arrangement are proposed design decisions, not statements that the source documents prescribe this exact trailer build.

[S1] Victron Energy, MultiPlus-II 120V — Description, section 2.1 (outputs, PowerControl, PowerAssist):
https://www.victronenergy.com/media/pg/MultiPlus-II_120V/en/description.html

[S2] Victron Energy, MultiPlus-II 120V — Installation, especially section 4.4 (AC connections, mobile chassis bonding, ground relay, output protection):
https://www.victronenergy.com/media/pg/MultiPlus-II_120V/en/installation.html

[S3] Victron Energy, MultiPlus-II 120V datasheet, 48/5000/70-95 column (inverter real-power ratings):
https://www.victronenergy.com/upload/documents/Datasheet-MultiPlus-II-120V-EN-.pdf

[S4] Victron Energy, MultiPlus-II 120V — Operation, section 3.1 (AC-input acceptance and charger-only behavior):
https://www.victronenergy.com/media/pg/MultiPlus-II_120V/en/operation.html

[S5] Schneider Electric, FAQ FA104355, 80%- versus 100%-rated breakers (continuous-load application):
https://www.se.com/us/en/faqs/FA104355/

[S6] Leviton, product 7313 (TT-30R, 30 A, 125 V):
https://leviton.com/products/7313