What are the pros and cons of using Bus bar chamber system vs MCCB panel board for LV distribution in a given system i.e TT? I know MCCBs are probably going to be more expensive and also easier to switch on after a fault. However, if there was a fault you would like an electrician to check out the faults and make sure that the fault doesn't appear again. Then it doesn't matter as if it was bs-88 fuses the electrician would come in check the fault and replace the bs-88 fuses after wards. I guess it also depends on the scale of the building or site.

For a given TT system, if the main incommer MCCB has earth leakage protection, will the outgoing MCCBs also need them?

Also talking about TT systems, would the fault never travel back to the main transformer or substation as who knows where the supply cables are coming from, hence needing RCDs?

Thanks.