question

garthvs avatar image
garthvs asked

Multiplus II and CT Clamp Error 24

We are experiencing issues when using the external CT clamp on the Multiplus II 5000 inverters.


We have recently installed around 15 systems with the external CT clamp and on approximately 4 or 5 of them we are experiencing Error 24 occasionally when grid power returns after a grid power failure. We are not using the second output of the inverter. We are running ESS.


From the Victron website:

"Error 24 is raised when a Multi or Quattro detects current flowing through the back-feed relay during a period when the relay should be open."


The error seems to occur more often when there are inductive loads like swimming pool motors connected to the non essential loads between the CT clamp and inverter. It also seems to occur more frequently the larger the non essential load is. From numerous tests on these sites, when we unplug the CT clamp the issue no longer occurs.


We have confirmed that are no issues with neutrals etc. The issue seems to be related to the surge in current through the CT clamp when the grid power returns and all non essential loads start up. We have tried multiple Grid codes as well as disabling LOM detection but nothing seems to lower the systems sensitivity when grid power returns.

Multiplus-IIerror
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3 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @garthvs

what firmware are you running, and just to be sure: did you check the 'external current sensor' option in ve.configure?

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garthvs avatar image
garthvs answered ·

Thanks Daniël

Firmware version is latest v481. We have tried with previous versions as well but the result was the same.

I have just checked now... the 'External current sensor connected' option is not enabled. We will test with this enabled tomorrow and I will revert.


2 comments
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Hi @garthvs

not selecting that option is most likely the cause, the external current sensor electrically replaces the internal sensor, so when the system doesn't know the external current sensor is installed, it thinks current is flowing through the unit while relays are open, and it flags this as a faulty relay (sticking relay)

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lifeingalicia avatar image lifeingalicia Daniël Boekel (Victron Energy Staff) ♦♦ commented ·
Hi thanks for the explanation. I too forot to check external sensor as I asumed it is a straight replacement.

So far error has not returned.


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usernamepasswordbs avatar image
usernamepasswordbs answered ·

I have the same problem and I have "external current sensor" checked in Ve.Config.

The largest load is connected after the CT and EM112 but before the Multiplus.

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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

MultiPlus-II 230V Datasheet 

VE.Bus Error codes

Additional resources still need to be added for this topic