tt system

[thekingiam]

doing a rewire for registration with elecsa, main earth looks about 2.5mm or 4mm? goes outside and sunk in concrete driveway sheathed but not protected.
my question is do i have to replace if my readings are fine? can i protect cable in conduit to overcome changing? don't fancy digging up concrete but if i have to do i need inspection pit, would i need dedicated spike meter?

 

[trev]

I seem to remember an equation for selecting the appropriate CSA earthing conductor, I also seem to recall rules governing cable protection etc from a book somewhere. I could be wrong mind you

 

[topcat]

I would think you will need to replace the cable as 2.5mm is small but I dont know the regs well for TT systems what is the Ze iam sure some one with more information and the regs to hand will help us out any time soon

 

[thekingiam]

haven't done Ze yet just trying to get an idea what trouble i am getting into

 

[thekingiam]

going away for the weekend,and just wanted an idea of what needs doing when i get back

 

[telectrix]

TBH, i would sink a new rod/s, earth pit and 6mm or 10mm back to MET. as buried rod that is inaccessible does not comply.

 

[thekingiam]

i think i have had an answer off you before telectrix, you said i only need my multifunctionmeter am i correct?

 

[thekingiam]

if i sunk 10mm would it have to be enclosed in galv conduit?

 

[telectrix]

see table 54.1 bgb.

 

[topcat]

I was told you can just check the Ze you dont need a earth rod tester I would have gone for 10mm but i like to over spec things

 

[thekingiam]

still have 16th bbb got to get bgb soon thanks will have a look when i get it.

 

[telectrix]

16mm if no mechanical protection

 

[thekingiam]

it's a short distance and will need 10mm for bonding so easier to just use 10mm

 

[telectrix]

it's a short distance and will need 10mm for bonding so easier to just use 10mm[/QUOTE
then you'll have to provide mechanical protection.

 

[thekingiam]

main rcd protection 80amp 30 ma protection/ cu 100 switch double rcd protection all circuits