Have got the 18th nic site guide,and unless I,m going blind,there are no max earth loop impedance tables for corresponding mcbs and fuses as were in the yellow OSG.I,ve been mugged!denmans ,both books £100 no vat of course
The OSGs are good for rainy days in a caravan in Wales.I dunno; its a reasonable attempt by someone to interpret the non plain English & ambiguities of book, written by some quasi scholars & academics, including the likes of NICEIC etc. As they all in cohorts with compiling BS7671 etc etc, and the On-site-guide or the Site Guide, shame they just can't have a directness of speech & writing in the first place.
Has got some pretty pictures, which the 'Regs' lacks.
Reply to the thread, titled "18th edition books. Site guide and on site guide" which is posted in UK Electrical Forum on Electricians Forums.