Victron MultiPlus GFCI tripping after an RV install is, in most cases, caused by a neutral-to-ground bond in the wrong place. The MultiPlus-II already handles bonding with an internal ground relay. This guide explains how that relay works, from Victron’s manual, and what to check.
Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.
Why Neutral and Ground Must Be Bonded in One Place Only
A GFCI compares the current going out on the hot wire with the current returning on neutral. If some returns through the ground wire instead, it trips. That happens when neutral and ground are tied together at more than one point downstream of the GFCI.
- On shore power, the bond is at the campground’s service panel.
- On inverter power, the inverter is the source, so the bond has to be at the inverter.
How the MultiPlus-II Ground Relay Works
From Victron’s MultiPlus-II 2x120V manual:
- The unit has a ground relay (relay H) that connects the AC output neutral to the chassis when no external AC supply is present.
- When shore or generator power is connected, the ground relay opens before the input safety relay closes.
- Victron says this “ensures the correct operation of an earth leakage circuit breaker connected to the output”.
- The ground relay is on by default in the factory settings.
So the MultiPlus-II switches the bond in and out automatically. You don’t need to add one.
Common Causes of Victron MultiPlus GFCI Tripping
- A bond in the RV’s distribution panel. Many RV panels are sub-panels, where neutral and ground must stay separate. A bonding screw or strap left in creates a second bond.
- The ground relay disabled in VEConfigure while a separate bond exists elsewhere, or no bond at all on inverter power.
- Neutral and ground swapped or shared on a downstream circuit or outlet.
- A GFCI on the input with the inverter’s own bond downstream. Victron recommends an earth leakage breaker on the AC output. For the 2x120V it names Blue Sea Systems GFCI breakers 309X or 310X.
- An appliance with real leakage, such as a water heater element. Unplug loads one at a time.
- Chassis not grounded. Victron says in a mobile install the casing must be connected to the vehicle chassis, because unplugging shore power also disconnects the shore ground.
Generators With a Bonded Neutral
Many portable generators bond neutral to their frame. Plugged into the MultiPlus input, that’s the source bond, the same as a campground pedestal. Inverter generators vary, so check the generator manual.
Full specifications for the MultiPlus-II are on Victron’s product page.
Worked Example: Checking an RV Distribution Panel
A typical RV with a MultiPlus-II 2x120V feeding a sub-panel. Here’s a step-by-step check, done by a qualified person with all power off:
- Disconnect shore power, switch the MultiPlus-II off and disconnect the battery.
- Open the RV’s AC distribution panel and find the neutral bar and ground bar.
- Check for a bonding screw or strap joining them. In a sub-panel fed by the MultiPlus-II, they should be separate.
- Confirm every circuit’s neutral goes to the neutral bar and every ground to the ground bar.
- Close the panel, reconnect, and test the GFCI outlets with their test buttons on both shore power and inverter power.
Worked Example: The Ground Relay in Each Mode
| Situation | Ground relay | Where the bond is |
|---|---|---|
| On shore power | Open | At the campground pedestal or service panel |
| On a bonded-neutral generator | Open | At the generator |
| Inverting from the battery | Closed | Inside the MultiPlus-II |
This automatic switching keeps exactly one bond in the system in each mode, which is what a GFCI needs to work correctly.
Testing GFCI Protection After Installation
- Press the test button on each GFCI outlet or breaker, on shore power and again on inverter power. It should trip both times.
- Use a plug-in GFCI tester at outlets downstream of a GFCI to confirm they’re protected.
- Check outlet wiring with a three-light outlet tester to confirm hot, neutral and ground are correct.
If everything trips and resets as expected in both modes, the bonding is set up correctly.
Where to Put GFCI Protection
Victron’s manual recommends an earth leakage circuit breaker on the AC output. In an RV, that typically means GFCI breakers in the panel the MultiPlus-II feeds, or GFCI outlets in wet areas such as the kitchen, bathroom and exterior outlets, following the RV’s original design and applicable codes. With the protection on the output side, it works the same whether power comes from shore, a generator or the inverter.
Chassis Grounding
In a vehicle, Victron says the MultiPlus-II’s casing must be connected to the chassis. Use the ground stud on the unit and a cable sized according to the manual. This keeps the system grounded when shore power, and its ground, is unplugged.
Settings to Leave as They Are
For most RV installs, the factory settings are right: the ground relay on, and the unit managing the bond automatically. Changing it in VEConfigure is only needed for special designs, such as installations with an external transfer switch that provides its own bond, and should be done under an electrician’s direction.
Split-Phase RVs
On the 2x120V model, both output legs share the same neutral, and the single ground relay bonds that neutral to ground when inverting. The same one-bond rule applies across both legs, and GFCI breakers on either leg work correctly once the panel’s neutral and ground are separate.
FAQ
Do Type A RCDs work?
Victron says yes. The internal transformer prevents DC current at the AC ports.
Should I turn off the ground relay?
Only in designs where the bond is made elsewhere, under an electrician’s direction.
Does the MultiPlus-II need a separate neutral-ground relay?
No. The internal ground relay handles bonding automatically when it’s enabled, as it is by default.
Will a GFCI on the RV’s inlet work with a MultiPlus-II?
Victron recommends placing earth leakage protection on the AC output. Protection on the output covers loads in every operating mode.
Sources: Victron MultiPlus-II 2x120V manual (installation, AC connection, configuration) (victronenergy.com, accessed Oct 2026).
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