Inverter Sub DB

[Thys LOW Elektries]

Good day, I have been asked to design a sub-db for a 3phase grid tie inverter system, that only works when Eskom works.
So far in the main DB, I have an Eskom main breaker that supplies power to the inverter sub-db and an inverter breaker that receives power from the inverter sub-db.
In the Inverter sub-db, I have an Eskom main breaker, an Inverter main breaker, and surge arrestors for Eskom and the Inverter.
I had also thought of including LED indicators for Eskom and the inverter power.
What else needs to be in the Inverter sub-db?

The pv contractor will do the PV installation and electrical work on his side and then just have to hook his system up to our network

Any advice would be welcome

[GCE]

Is the system str grid tie , no Batteries ?

It sounds like it - then all you need is a surge arrestor on main incoming and a CB feeding the inverter , no sub DB needed .

Inverter will have a CT that will be on the main incomer to monitor usage and stop feed back , if needed

[Thys LOW Elektries]

The only reason I was thinking of a sub DB is to give the PV installer a place where they can disconnect the power safely when they need to work cause they don't have a key to gain access to the main db. Also one can isolate the supply safely before the inverter is installed

[GCE]

The only reason I was thinking of a sub DB is to give the PV installer a place where they can disconnect the power safely when they need to work cause they don't have a key to gain access to the main db. Also one can isolate the supply safely before the inverter is installed

If there is distance from the DB then you would need to have an isolator at the inverter that they can use to switch off

[Thys LOW Elektries]

Yip, a distance, plus the main DB is in a service shaft that is not visible from where the inverter is installed.
When you say Isolator, do you mean something like a CBI 4x4 60Amp three-phase isolator or do you mean a 4-pole Isolator in a DB?

[GCE]

Yip, a distance, plus the main DB is in a service shaft that is not visible from where the inverter is installed.
When you say Isolator, do you mean something like a CBI 4x4 60Amp three-phase isolator or do you mean a 4-pole Isolator in a DB?

I would put a 4 pole CB in the DB and a normal isolator , waco/ crabtree isolator next to the inverter - On a str grid tie , as soon as grid drops then the inverter switches off - It needs grid as it follows the grid / sync with grid