A question about neutral-earth bonding for a Multiplus 24/3000/70-16 off-grid system, with Sunny Boy 2500HF-30 solar inverter and generator backup. In the UK.
I have recently taken over this installation which was originally installed (in 2015) with a N-E bond in the consumer unit (elsewhere named breaker panel, distribution board etc), even though the Multiplus has an internal N-E bond when there is no AC input. When AC input is present (in our system from a generator), the Multiplus N-E bond is opened and the system uses the N-E bond at the generator. The bond in the CU was later removed (probably around 2019), not by the original installer and not by me.
My understanding is that there should not be a N-E bond in the consumer unit when the Multiplus (or our generator) has it. I have asked the original installer why the N-E bond in the CU was made, the reply was 'I don’t think the sunny Boy will work without it as it shows a PE fault'. Well, the Sunny Boy doesn't show a PE fault and it works fine.
Thanks for reading this far, here are my questions:
1. Does anyone have any experience of a PE fault using Sunny Boy inverters?
2. Are there any circumstances where a CU should have a N-E bond in this kind of installation?
