Aah its complex. not all inverter systems are equal, transformerless systems effectively connect one side of the DC bus or battery  to one side of the mains and then flip which side 50 times a second. Clearly a fault to earth in such a system blows something, but if that is the supply ADS or the semiconductor switches that do the commutation is a guess !

Inverters with transformers have a floating DC side, although for EMC reasons one side often is earthed, or at least earthed to RF, if not connected directly.

There are quite a few good explanations on maker's websites.
Mike

Thanks, that makes sense, I'll have a look at the websites. 

Hi Jake. 

I agree with your assessment regarding the requirements for embedded cables in accordance with the COP. However, it is still advisable to avoid embedding DC cables whenever possible and to also minimise their length if possible. The guidance also says functional earthing of one of the current-carrying conductors is generally not recommended but may be necessary to comply with the module manufacturer’s requirements to mitigate the effects of Potential Induced Degradation (PID). MCS-approved inverters are typically equipped with integrated Arc Fault Circuit Interrupters (AFCI) for DC arc-fault protection and short circuit protection. These inverters continuously monitor floating systems for earth insulation resistance using insulation monitoring devices suitable for IT systems. Additionally, they provide surge protection, grid monitoring, anti-islanding protection, and temperature protection, thereby safeguarding the DC side of the system.

I have just completed a Solar /PV & EESS course this week and It is also worth noting that some insurance companies now mandate the inclusion of fire shutdown systems. This often necessitates the use of module-level power electronics, such as microinverters, which have the capability to shut down independently in the event of a fire.

- Andrew