Having determined that the steel structure of a detached concrete sectional garage is an extraneous conductive part (0.34 ohms when measured between the CPC on the house downstairs ring final and the steelwork ), I know that I have to provide main bonding to the steel work from the MET .
Question is, do bonding conductors need to be mechanically protected ? There is the potential to route it under the block paving slabs in the sand into the garage without too much disruption to the driveway.
The existing supply is in 2.5mm 3 core SWA fed from a 13A FCU in the kitchen, the G/Y core providing the CPC of the distribution circuit to the garage.
Also, what is the CSA of the armour on 2.5mm SWA ? Is it feasible to use this as (a section of) the bonding conductor ?
[EDIT] I have ascertained that the armour has a CSA of 19mm (thanks wiki) Is it therefore permissable to terminate some 10mm to the armour where it leaves the house via a lug or pirhana nut, and then in the garage do the same and terminate on steelwork ?
Question is, do bonding conductors need to be mechanically protected ? There is the potential to route it under the block paving slabs in the sand into the garage without too much disruption to the driveway.
The existing supply is in 2.5mm 3 core SWA fed from a 13A FCU in the kitchen, the G/Y core providing the CPC of the distribution circuit to the garage.
Also, what is the CSA of the armour on 2.5mm SWA ? Is it feasible to use this as (a section of) the bonding conductor ?
[EDIT] I have ascertained that the armour has a CSA of 19mm (thanks wiki) Is it therefore permissable to terminate some 10mm to the armour where it leaves the house via a lug or pirhana nut, and then in the garage do the same and terminate on steelwork ?