FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Warning!!! The following is an extrapolation of what I think the system looks like..... I could be wrong.
I looked up Reliance transfer switches and they all seem to only switch the Hot line and not the neutral line.
With that in mind, I sketched out what the circuit might look like. Please look it over and let me know if this seems accurate to you.
Assuming this properly represents the circuit, a few things jump out at me.
1) First, there is a ground loop (dotted green in the image below). The ground wire between the growatt and xfer switch (red X) should be disconnected. The transfer switch and downstream circuits are adequately grounded with just the connection to the main panel. The ground loop is not likely to be causing the GFCI to pop but there is a small chance that disconnecting the marked ground wire could mask the problem.
Note: The AC-Ground in and AC-Ground out is tied together on both the GFCI and the Growatt.
Once the ground loop is taken care of, it will look like this:
2) The next thing I noticed is that there is only one NG bond in the system. When the xfer switch is wired as shown above that single bond will always be seen, regardless of whether the power is coming from the Growatt or grid. This explains why the tester shows OK when the xfer switch is in place but shows an error when the xfer switch is not wired in.
3) Finally, the Neutral from the Main Box is tied to the Neutral out of the Growatt. This means the Neutral-in of the Growwatt and the Neutral-out of the Growatt are tied together. I don't know what the Growatt will do in this situation, but I suspect this is the root cause of the GFCI poping. I am going to have to think about what could be done to fix this.
Meanwhile, try this:
With all loads switched to Off in the transfer box and the inverter on UTIL.... does the GFCI pop?
With all loads switched to Off in the transfer box and the neutral disconnected as shown below, does the GFCI pop when in UTIL mode?
I looked up Reliance transfer switches and they all seem to only switch the Hot line and not the neutral line.
With that in mind, I sketched out what the circuit might look like. Please look it over and let me know if this seems accurate to you.
Assuming this properly represents the circuit, a few things jump out at me.
1) First, there is a ground loop (dotted green in the image below). The ground wire between the growatt and xfer switch (red X) should be disconnected. The transfer switch and downstream circuits are adequately grounded with just the connection to the main panel. The ground loop is not likely to be causing the GFCI to pop but there is a small chance that disconnecting the marked ground wire could mask the problem.
Note: The AC-Ground in and AC-Ground out is tied together on both the GFCI and the Growatt.
Once the ground loop is taken care of, it will look like this:
2) The next thing I noticed is that there is only one NG bond in the system. When the xfer switch is wired as shown above that single bond will always be seen, regardless of whether the power is coming from the Growatt or grid. This explains why the tester shows OK when the xfer switch is in place but shows an error when the xfer switch is not wired in.
3) Finally, the Neutral from the Main Box is tied to the Neutral out of the Growatt. This means the Neutral-in of the Growwatt and the Neutral-out of the Growatt are tied together. I don't know what the Growatt will do in this situation, but I suspect this is the root cause of the GFCI poping. I am going to have to think about what could be done to fix this.
Meanwhile, try this:
With all loads switched to Off in the transfer box and the inverter on UTIL.... does the GFCI pop?
With all loads switched to Off in the transfer box and the neutral disconnected as shown below, does the GFCI pop when in UTIL mode?