r1 + r2 values

[Sparky_Ben]

I am going through my college notes for my AM2 starting tomorrow and i am struggling to find the table which shows allowable R1+R2 values i only have the new green books to hand any advise would be great however i think it is the old red books that are provided, i have a feeling i am missing something probably staring me in the face,

 

[londonlec]

I cant remember the AM2 but its rare you will need to use the tables which shoe R1 and R2 figures.

You will usually only require the maximum Zs figures, which are in the regs (100% values). Obviously max Zs has to be compliant to ensure your fuse/cb will blow within the allowed time.

 

[Sparky_Ben]

I think it was something that came up on the refresher, it could be the values regarding cable size etc, i feel i am confusing myself somewhat now

 

[leesturgess]

page 166 red osg values of resistance/metre or (r1+r2)for copper and aluminium conductors at 20 c