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cheers electro for the info so far. ignore the seperate earth question-was just checking. as swa is 3 core and not relying on sheath as main earth then all is well.

single phase 100A? correct me if wrong but although some propertys have 80 or 100 amp slow blow cut out, you can only physically draw 80A from any single phase supply? an engineer told me this and i just took his word for it.

think ill go with 25mm for what its worth and no questions asked. price is good so not bothered really and will avoid calcs as you mentioned :)

if i have seperate earth conductor combined within swa (3 core) and its earthed via nut, banjo and gland on isolator, surely its not mandatory to bond at plastic cu? may do it anyway but any advice most appreciated mate.
all companys i have worked for, have fitted 2 core subs and seperate earth to mutli story appartments etc but not bonded swa sheath at final cu.same goes with 3 core subs too. suppose its good practice but not as necessary with 2core and seperate earth

also, wont swa of say 5m take 100A? correct me if wrong? still going with 25mm but just out of interest

sorry, meant 16mm swa taking 100A+ ?
 
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cheers electro for the info so far. ignore the seperate earth question-was just checking. as swa is 3 core and not relying on sheath as main earth then all is well.

single phase 100A? correct me if wrong but although some propertys have 80 or 100 amp slow blow cut out, you can only physically draw 80A from any single phase supply? an engineer told me this and i just took his word for it.

think ill go with 25mm for what its worth and no questions asked. price is good so not bothered really and will avoid calcs as you mentioned :)

if i have seperate earth conductor combined within swa (3 core) and its earthed via nut, banjo and gland on isolator, surely its not mandatory to bond at plastic cu? may do it anyway but any advice most appreciated mate.
all companys i have worked for, have fitted 2 core subs and seperate earth to mutli story appartments etc but not bonded swa sheath at final cu.same goes with 3 core subs too. suppose its good practice but not as necessary with 2core and seperate earth

also, wont swa of say 5m take 100A? correct me if wrong? still going with 25mm but just out of interest

sorry, meant 16mm swa taking 100A+ ?


Hi MTI

A 100amp fuse will take 100 amps +
bonding a Cu if its plastic No,you will need to terminate the earth into the MET
25mm swa 145amps
16mm saw 110amps
these are rough guides no CF taken into account, as i dont know your exact run.

regards
 
hi electro, sorry if we got our lines crossed-bonding plastic cu? all i meant was protecting/earthing the sheath of swa at both ends. obviously with plastic cu and swa, there is nothing to terminate swa into. nobody i know would put a gland on swa at cu just to finish the job off nicely. i dont mean glanding it to plastic cu obvoiusly but just 'leaving loose' within a plastic 50x50 trunking or something as it comes out of floor as an example.
right, so metal clad isolator at mains cut out,
swa glanded into isolator,
25mm d. insulated tails from metal clad isolator into metre,
banjo on gland too with flying lead onto met in isolator box?
earthing conductor within swa onto met in isolator box or straight to met at supply and one back to metal box?
other thing is, i have a tns with clamp on incoming feed to house-no pme-bummer!
plus to make it worse, as normal in my area, next doors house is daisy chained into my job! would you link both clamps? i think supply company say no.

i ended up with this on a job last week and had to use a spike as no incoming earth
 

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