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Multiplus tripping 50 amp shore breaker plus error code 24: Switch-over system protection initiated

Okay, but I do not like that arrangement for cross strapping subpanel L1 & L2 when off-grid unless there is a time delay on cross-strapping after grid drops. Any loads on L2 side gets hit with a phase reversal.

If you have a refrig or AC compressor powered on L2 side and grid goes out, compressor gets hit with a 180 degree phase reversal that causes high surge current unless there is a long dead time delay.
 
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@RCinFLA
These are specifically made/marketed to the 50 amp Class A and 5th wheel group. It allows for you to run your rig from the several different currents and available voltages in most campgrounds. It's sort of the cheapest way to get an inverter and still be able to plug into the split phase 50 amp when available.
It's not really made or useful for non mobile applications but very RV friendly.
 
RCinFLA said:
Okay, but I do not like that arrangement for cross strapping subpanel L1 & L2 when off-grid unless there is a time delay on cross-strapping after grid drops. Any loads on L2 side gets hit with a phase reversal.

If you have a refrig or AC compressor powered on L2 side and grid goes out / unplugged, compressor gets hit with a 180 degree phase reversal that causes high surge current unless there is a long dead time delay.
Click to expand...
Assuming they are 120V appliances L1 and L2 are inphase. The only devices affected are any potential 240V loads, when grid power stops then they will see 0V as both L1 and L2 are in phase.
 
Brucey said:
Assuming they are 120V appliances L1 and L2 are inphase. The only devices affected are any potential 240V loads, when grid power stops then they will see 0V as both L1 and L2 are in phase.
Click to expand...
When grid drops, the L1 side is immediately picked up by inverter at L1 grid original phase. L2 previously on 240vac split-phase grid gets its 120vac to neutral L2 side phase flipped 180 degrees to L1 side phase by cross-strapping relay.

If the cross-strapping delays engagement, allowing any AC motors to stop, you avoid motor kick back surge current. On a compressor you also have to deal with start-up under built up refrigerant head pressure so should wait 5 minutes or more to repower compressors. Refrigerator compressors usually just overheat during short cycle restart attempt and trip over-temp shutdown which can take an hour or more to cool down enough to restart compressor.
 
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RCinFLA said:
When grid drops, the L1 side is immediately picked up by inverter at L1 grid original phase. L2 previously on 240vac split-phase grid gets its phase flipped 180 degrees to L1 side phase by cross-strapping relay.

If the cross-strapping delays engagement, allowing any AC motors to stop, you avoid motor kick back surge current. On a compressor you also have to deal with start-up under built up refrigerant head pressure so should wait 5 minutes or more to repower compressors.
Click to expand...
Any 240V loads will see 0V once grid drops. ACs etc will shutdown. Because the 2X120V only inverts 120V. The risk of grid power resuming and short cycling the compressor etc would be there irrespective of the 2x120.
 
My understanding is generally a 240V appliance is pretty rare on most RVs except the mega ones, with goal generally being to supply both sides of the panel with 120V (in phase).
 
Back to the original post question.

You have to be very careful of AC input transfer switching to a single AC input hybrid inverter.

You must always ensure the inverter's pass-through relay has released open before connecting/reconnecting or changing AC sources. This can take up to a couple seconds for pass-through relay to release after disconnecting AC input. Don't reconnect AC input again until pass-through relay releases.

Inverter phase locks to AC input then closes pass-through relay putting inverter in parallel with AC input. If you immediately transfer switch its AC input to another random phased AC source (like immediately jumping from generator to grid) it can cause high surge current from AC phase mismatch between inverter and newly applied AC source.

This can damage pass-through relays and even damage inverter. One result of this is welded relay contacts that get stuck together.

The one time you said it worked, is likely the one time you were lucky and the inverter phase happened to match the AC input phase at the instant you applied the AC input.

Check AC inputs of inverter when off grid to ensure there is no AC voltage present on AC input terminals (indicating pass-through relay is open). If there is AC voltage you may have welded together pass-through relay contacts, likely caused by transfer switching between two different live AC sources too quickly.
 
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RCinFLA said:
Back to the original post question.

You have to be very careful of AC input transfer switching to a single AC input hybrid inverter.

You must always ensure the inverter's pass-through relay has released open before connecting/reconnecting or changing AC sources. This can take up to a couple seconds for pass-through relay to release after disconnecting AC input. Don't reconnect AC input again until pass-through relay releases.

Inverter phase locks to AC input then closes pass-through relay putting inverter in parallel with AC input. If you immediately transfer switch its AC input to another random phased AC source (like immediately jumping from generator to grid) it can cause high surge current from AC phase mismatch between inverter and applied AC source.

This can damage pass-through relays and even damage inverter. One result of this is welded relay contacts that get stuck together.

The one time you said it worked, is likely the one time you were lucky and the inverter phase happened to match the AC input phase at the instant you applied the AC input.

Check AC inputs of inverter when off grid to ensure there is no AC voltage present on AC input terminals (indicating pass-through relay is open). If there is AC voltage you may have welded together pass-through relay contacts, likely caused by transfer switching between two different live AC sources too quickly.
Click to expand...
This inverter is doing some strange stuff. with no input ac, while inverting, it is sending ac back out the input legs. breaker is off and it is lighting up a few lights on my surge protector. dam thats not good. also when inverter is switched completely off and I have 120v on input, I see 120v between ground and L1,L2,and common.
 
rockbust said:
This inverter is doing some strange stuff. with no input ac, while inverting, it is sending ac back out the input legs. breaker is off and it is lighting up a few lights on my surge protector. dam thats not good. also when inverter is switched completely off and I have 120v on input, I see 120v between ground and L1,L2,and common.
Click to expand...

That really sounds like the unit is faulty with a shorted relay. That relay should open when inverting or when off.
 
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