It appears from everything that I have read that for a TT system it's normal to use a metal consumer unit with normal 100A main incoming switch and RCBO's for circuit protection.
This is based on the unprotected live conductors, meter tails and busbar being well protected and supported reducing the risk of fault. Therefore the risk caused by high earth loop impedance and a live conductor contacting the metal consumer unit is very low.
It also from catalogues etc to be normal practice to introduce SPD's into these CU's along with a circuit breaker to protect them. This means additional wiring which presumably is not double insulated and does not benefit from additional support.
I could avoid the above with an external SPD but that adds cost and just makes the installation more cluttered.
Am I correct that industry believes it's acceptable to use spd's internally on TT protected CU's along with the additional risk the wiring would cause?
