Why are main bonding conductors so big?

[Sidewinder]

I've used a few of these http://www.cablejoints.co.uk/upload/Earth_Inspection_Housing___ERH_01W___Concrete_Earth_Pit.pdf recently due to the environment, & have 4 on stock ready to go in at the same client.

 

[steptoe]

I used to use all metal inspection boxes at a time,

but it seems getting a back axle for a GT turkey, is easier in England, than getting an all metal TOBY box is. :|

 

[m4tty]

I use the Furse Concrete Pits, the plastic and fibreglass ones are just pony....

+1 I only use the concrete ones. Proper job