question

svcrazypirates avatar image
svcrazypirates asked

My Multiplus 12/3000/120 trips the shore power pedestal breaker.

Last year I had an Victron installer install a Multiplus on my boat while I was on anchor (no shorepower). Everything worked including when running my generator. While moving the boat north for hurricane season I stopped at a couple of marinas and plugged into shorepower with no problem ie. everything worked as it should. When I arrived at my home marina and tried to plug into shore power my Multiplus tripped the breaker on the shore power pedestal (my marina recently upgraded all power pedestals). When I disconnect the Multiplus AC Input and AC Output and connect them together (input directly to the output), everything on the boat works as it should. So by taking the Multiplus out of the equation I can connect to shorepower and operate normally. Any ideas on why I'm having this problem?

Multiplus-II
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

5 Answers
kevgermany avatar image
kevgermany answered ·

I guess your home marina has lower allowable current than the other marinas.

There's a user configurable AC current limit in the multiplus. You can change the setting in VRM.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

derrick thomas avatar image
derrick thomas answered ·

Have you adjusted the input current limit? Also is the shore connection a GFCI?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

svcrazypirates avatar image
svcrazypirates answered ·

I have adjusted the AC input current down from 30 amps to 20 amps and up to 50 amps with no change to my issue. As soon as I throw the shipboard shore power breaker the GFCI breaker on the dock pedestal trips. The marina electrician says I have a ground fault on my boat BUT when I take the Multiplus out of the equation (powered off and all leads disconnected), I receive shore power to my boat no problem. So logical troubleshooting points to the Multiplus as the issue. Can the Multiplus have a ground fault issue?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image seb71 commented ·

There is a ground relay which normally closes (connecting N with PE) in inverter mode and should open when AC In is connected with AC Out.


If the ground relay is faulty I think you should get an error.

-1 Like -1 ·
waninae39 avatar image
waninae39 answered ·

if there is a GFI connection inline , them the Multiplus will trip

its best to add a surge suppressor device to the input , as they also check the connections for proper polarity etc

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

derrick thomas avatar image
derrick thomas answered ·

This seems to be a fairly common issue with the multiplus, search the board here for "GFCI trips" or something similar and you will find several threads on the subject. There seems to be 2 groups on this issue. One group the multi will connect and start charging but the shore GFCI trips when the charger drops to float. The other group the GFCI trips as soon as the incoming power is passed thru.

If you are in the former group, you might try temporarily changing the charging parameters so the absorption and float are the same voltage, maybe a compromise somewhere between the 2 voltages. I suspect that the issue has something to do with the voltage drop thru the transformer when it drops to float, and a split second change in the ac power as a result. Just a theory on my part, I have not had opportunity to test that theory and may be way off the mark.

If you are in the latter group, you might try disabling the neutral to earth bonding relay in the multi. It may or may not make a difference, but might be worth checking. Do this at your own risk, as there will be no bond if shore power is not present. This can be very dangerous, so again, at your own risk. Know the dangers and decide for yourself.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.