Zs too high at distribution boards

[malcolmsanford]

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.

 

[IQ Electrical]

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.

 

[kmcgold]

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.

 

[Dave_]

yeah do a calc..... best way...