question

@Boater

The ground relay is closed when inverting to make its own neutral earth link for the safety circuits to work.

It opens once the inverter has established whether the incoming power meets parameters for connection.

Power assist does not affect the relay open and close. Power assist means power is added from your baterry for a load if needed to prevent overloading or tripping the incoming breaker.

More on each function can be found here.

Thanks much for your reply. I still need a bit more clarification because it seems that something still doesn't quite make sense.

If ground relay operation is dependent on whether the inverter is inverting, and Power assist affects when the inverter is inverts, wouldn't Power assist necessarily affect ground relay operation?

I guess I could ask the question a different way. With both Power assist and Ground relay options ON, does the inverter tie neutral to ground when connected to AC and the inverter is assisting (inverting)?

@Boater

There are quite a few threads on here which pretty much say the same thing.

There must be an issue you have not oicked up yet with wiring or an appliance.

I will start you off on one here.

@Boater

If the relay in orange is closed the one in yellow is open. The yellow one is the ground relay.

And to comply with type approval requirements the ground relay does not make contact until just after the backfeed relay opens (since I hear you ask @Boater) so there is no point in time when both are closed.

Good morning, I think your system configuration is perfect and you don't need to make any changes. When you connect your system to shore power, there would be no problems with the position of N and L if only normal charged loads were present inside your boat (or camper) such as a battery charger, a hair dryer, microwaves, etc. Even if there was an inverter connected to the battery there would be no problems. But inside your system there is also an inverter combined with the charger. When using your multiplus appliance, your installer has RIGHTLY installed a 0.03 A differential which is needed for your safety. It should always be installed on all inverters ( even if they are not combi ) This output differential to be installed correctly must be CONNECTED WITH THE NEUTRAL AND THE CHASSIS TOGETHER ) . Only in this way and safe, I have seen many installations where the L-N outputs are connected to the L-N inputs, but this way is useless. Your multiplus appliance therefore needs, being combined with an inverter, that the inputs (L - N) be respected. When you connect to Shore power, I imagine you are using a non-reversible industrial plug. You can't know the position of L-N if it's wired the right way or the same as yours. So if you only use the battery charger function you won't have any problems, in this case the position of the terminals doesn't matter, but as soon as the inverter turns on, output N is put in communication with the chassis and with the ground of the plug where you are connected. (shore power). If the plug is against your L it becomes N and N becomes L . The consequence is that L is connected to ground and the RCD trips. To solve this problem I think you need to have a reversible plug, where you can easily change your connection. Or equip yourself with two power cables and before connecting, check where the L is with a phase finder (like a pen that plays). You must not exclude the security that vicron has within its multiplus.

Good morning, I think your system configuration is perfect and you don't need to make any changes. When you connect your system to shore power, there would be no problems with the position of N and L if only normal charged loads were present inside your boat (or camper) such as a battery charger, a hair dryer, microwaves, etc. Even if there was an inverter connected to the battery there would be no problems. But inside your system there is also an inverter combined with the charger. When using your multiplus appliance, your installer has RIGHTLY installed a 0.03 A differential which is needed for your safety. It should always be installed on all inverters ( even if they are not combi ) This differential to be installed correctly must be CONNECTED WITH THE NEUTRAL AND THE CHASSIS TOGETHER ) . Only in this way and safe, I have seen many installations where the L-N outputs are connected to the L-N inputs, but this way is useless. Your multiplus appliance therefore needs, being combined with an inverter, that the inputs (L - N) be respected. When you connect to Shore power, I imagine you are using a non-reversible industrial plug. You can't know the position of L-N if it's wired the right way or the same as yours. So if you only use the battery charger function you won't have any problems, in this case the position of the terminals doesn't matter, but as soon as the inverter turns on, output N is put in communication with the chassis and with the ground of the plug where you are connected. (shore power). If the plug is against your L it becomes N and N becomes L . The consequence is that L is connected to ground and the RCD trips. To solve this problem I think you need to have a reversible plug, where you can easily change your connection. Or equip yourself with two power cables and before connecting, check where the L is with a phase finder (like a pen that plays). You must not exclude the security that vicron has within its multiplus.

Hi Boater, did you find the problem? I have exactly the same thing happening on a new Multiplus install and it has me and my electrician stumped!