Direct Buried cables within a controlled area and what constitutes mechanical protection

Yeah Disconnectors at the SCBs. If there were late starts and R<iso on a regular basis then yes I would suggest full protection using twin wall duct etc. I have been within the Photovoltaic engineering sector since 2005 moving into large scale in 2011 with first hand knowledge of the majority of UK large scale solar farms and have seen multiple failures of direct buried cables usually down to poor installation. Usually faults appear once the ground starts too settle back after excavation. 

This particular site has been running like clockwork for almost 4 years and not a single incident its also an incredibly wet site. Cable routing was done properly to the manufactures guidelines laid with cable sand and plenty of segregation between poles. Cable manufacturer specifics states suitable for direct burial as double insulated also.

I have seen multiple failures when cables are pulled through ducts and then ducts get full of water rising to insulation failures leading to dead shorts between DC poles sometimes causing arcing. 

A really good quality EPC constructed the site. I mean after almost 1700 site visits to solar farms in recent years I know the good bad and ugly!! 

In my opinion the consultant who has raised this issue does not know Photovoltaics very well and not asking about any protection measures in place which monitor the insulation values constantly and if detected will shut down inverter. usually all these sites are built using IT floating earth method so monitoring  GFDI protection devices are essential.

Yeah Disconnectors at the SCBs. If there were late starts and R<iso on a regular basis then yes I would suggest full protection using twin wall duct etc. I have been within the Photovoltaic engineering sector since 2005 moving into large scale in 2011 with first hand knowledge of the majority of UK large scale solar farms and have seen multiple failures of direct buried cables usually down to poor installation. Usually faults appear once the ground starts too settle back after excavation. 

This particular site has been running like clockwork for almost 4 years and not a single incident its also an incredibly wet site. Cable routing was done properly to the manufactures guidelines laid with cable sand and plenty of segregation between poles. Cable manufacturer specifics states suitable for direct burial as double insulated also.

I have seen multiple failures when cables are pulled through ducts and then ducts get full of water rising to insulation failures leading to dead shorts between DC poles sometimes causing arcing. 

A really good quality EPC constructed the site. I mean after almost 1700 site visits to solar farms in recent years I know the good bad and ugly!! 

In my opinion the consultant who has raised this issue does not know Photovoltaics very well and not asking about any protection measures in place which monitor the insulation values constantly and if detected will shut down inverter. usually all these sites are built using IT floating earth method so monitoring  GFDI protection devices are essential.