Advice tt installation industrial scrap yard

[graham123]

Testing an industrial scrap yard. Supply is a tt, with a 30ma three phase 100 4293 main switch which feeds main panel and then off to offices etc. 30ma RCBOs all downstream. Am I right in presuming a 30ma main rcd is ok and will protect all circuits obviously no discrimination between this and the ones downstream so will be unable to test rcds fully. What would I write in the max zs box for each circuit? Would it be 1667 for each?

 

[james_t87]

What type of cables come off the main panel? Swas?

 

[Simonslimline]

Is the upfront RCD not a time delayed S type?

 

[graham123]

It's not a time delayed and cables leaving main panel are swa

 

[Engineer54]

Do you consider that this 3 Phase main panel RCD's protection is correct??