VFXR 3024 pops grid RCD after a while

[Echo5]

Hi All

I have a VFXR 3024 which keeps popping an RCD on the main electricity panel after about 2 minutes of pulling power from the grid. Everything else carries on working correctly. I am attempting to get the inverter to charge the batteries in Mini-Grid mode.

The inverter is part of a FlexPowerOne system (so I assume its wired correctly internally) and there are no other external components. If the incoming grid connection has it's ground wire connected inside the inverter, the RCD pops immediately as soon as the grid is connected. Disconnecting the ground wire, the inverter will happily charge for about 1-2 minutes then pop the RCD. The RCD is 30mA - would a less touchy higher rated one be advisable? The inverter charge current is set low at 2Amp.

Any advice appreciated.

[raysun]

One consideration is the Residual Current Device is doing what it's designed to do.

If the incoming grid connection has it's ground wire connected inside the inverter, the RCD pops immediately as soon as the grid is connected.

I'd take this as a fairly large red flag. Either there is a ground fault in the wiring, or the RCD may be defective.

The inverter is part of a FlexPowerOne system (so I assume its wired correctly internally)

One would hope so, but shouldn't bet one's life on it. A walk-through of the internal wiring is a bit of a hassle, but necessary, IMO.

[fcwlp]

The FlexPowerOne comes with the Neutral bonded to the Ground. Remove the N-G bond and test.

[raysun]

VFXR3024 is mentioned. Is this the "-E" model?

FlexPower One - Grid Tied circuit diagram

Download version here: https://www.outbackpower.com/downloads/ ... id_tie.pdf

[Echo5]

Thank you both for the advice!

fcwlp:> The FlexPowerOne comes with the Neutral bonded to the Ground. Remove the N-G bond and test.

Yes, as raysun suggested, I did have a look at the internal wiring and there is a very obvious, rather largish, green and yellow ground wire running from the ground bus bar up to the neutral bus bar inside the VXFR3024. My experience at these things is not extensive but it does seem odd to tie these two together. What would be the purpose of this and why it would be done?

raysun:> VFXR3024 is mentioned. Is this the "-E" model?

Yes it is. Clearly labeled VFXR3024E on the side of the device. What is the significance of this model version? Thank you for the circuit diagram - if I am interpreting it correctly there is no connection between the ground and neutral in it (as fcwlp suggested above).

[fcwlp]

Yes, as raysun suggested, I did have a look at the internal wiring and there is a very obvious, rather largish, green and yellow ground wire running from the ground bus bar up to the neutral bus bar inside the VXFR3024. My experience at these things is not extensive but it does seem odd to tie these two together. What would be the purpose of this and why it would be done?

That is the N-G bond to remove. The N-G bond needs to occur in only one location, otherwise there can be current flowing in the ground loop created which is likely tripping your RCD. In the US the electrical code has this bond made just after the power enters the meter. In the US a RCD is not used on the incoming power but rather GFIs are used at the outlets or circuits supplying the outlets.

[Echo5]

SUCCESS

Removing the wire linking the ground and the neutral busses in the inverter appears to have fixed the issue. The inverter has been running in Mini-Grid for several hours now with no problems. The system rarely got more 2 minutes before.

Thank you all for your help. It is much appreciated.

[fcwlp]

SUCCESS

Removing the wire linking the ground and the neutral busses in the inverter appears to have fixed the issue. The inverter has been running in Mini-Grid for several hours now with no problems. The system rarely got more 2 minutes before.

Thank you all for your help. It is much appreciated.

Congrats