The easiest solution really is to fit RCD/RCBO but as we all said investigation should be in order. Im my experience if this is an older installation with all the entails it may be the original design called for a type 1 or B MCB and over the years for various reasons other types have been fitted.
 
If you let me know the distribution circuit cable details (CSA, approximate length, is the swa alone being used as the cpc) then I can calculate the R1+R2 and we can then see if there is a fault.

The R1+R2 added to your Ze of 0.08 Ohms will give us a worst case scenario, with actual parallel paths, your measured Zs should be lower than my calculated figure.
 
If you let me know the distribution circuit cable details (CSA, approximate length, is the swa alone being used as the cpc) then I can calculate the R1+R2 and we can then see if there is a fault.

The R1+R2 added to your Ze of 0.08 Ohms will give us a worst case scenario, with actual parallel paths, your measured Zs should be lower than my calculated figure.


:) good post.
 

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Green 2 Go Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses Heating 2 Go
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Advert

Daily, weekly or monthly email

Thread Information

Title
Zs too high at distribution boards
Prefix
N/A
Forum
Electrical Wiring, Theories and Regulations
Start date
Last reply date
Replies
43

Advert

Thread statistics

Created
knasher,
Last reply from
Dave_,
Replies
43
Views
14,247

Advert

Back
Top