Question EG4 12000XP - Can GRID Input Work Without a Utility Neutral?

Hello everyone,

I hope someone from the EG4 technical team or an experienced installer can help me with a question about the EG4 12000XP.

I have carefully read the EG4 12000XP User Manual, especially section 8.4 (Neutral-Ground Bonding). I understand that the AC input and AC output share a common neutral, the neutral is never disconnected internally, and the inverter can create the Neutral-to-PE bond using the N-PE Connect setting if required.

However, my installation is very unusual, and I have not been able to find any information about this situation.

The system will be installed in a rural area of Cuba. The utility company does not provide a neutral conductor or an equipment grounding conductor. Only two energized conductors come from the utility line.

For many years, the house has been powered through an old tap-changing transformer/autotransformer located before the main electrical panel. The purpose of this transformer is not isolation but voltage regulation because the local utility voltage is very unstable.

One incoming utility conductor passes directly through the transformer, while the other is connected to one of several taps to decrease the output voltage. After leaving this transformer, the house receives approximately 127–130 VAC to power all the household loads. There has never been a dedicated neutral conductor or an earth grounding conductor in the installation.

I am planning to install an EG4 12000XP with batteries and solar panels, and I would like to eliminate the old transformer if possible and connect the utility directly to the inverter.

My questions are:

1. Can the GRID input of the EG4 12000XP operate with only L1 and L2 connected, without a utility neutral conductor?

2. If there is no utility neutral available, should the GRID Neutral terminal remain unconnected?

3. If this configuration is not supported, what is the manufacturer's recommended solution?

4. Would an isolation transformer or another type of transformer be required?

5. If the N-PE Connect function is enabled, can the inverter create the proper system neutral for the AC output even though the utility supply does not include a neutral conductor?

6. Is there an official wiring diagram or application note for this type of utility supply?

I would really appreciate any guidance from the EG4 engineering team or anyone who has experience with this type of installation.

Thank you very much for your time.