Minimum values of insulation resistance

gkenyon:

AJJewsbury:

Therefore each circuit can pass an insulation test, but the whole board can fail, so what do you do next?

But there is no BS 7671 value for a single circuit to pass/fail - just one for the complete DB's worth - 1MΩ*


If the whole DB fails, then it's a fail.


   - Andy.


* for initial verification at least.

 

Regulation 643.2 says nothing about DBs


The requirement is:

643.3.2 The insulation resistance measured with the test voltages indicated in Table 64 shall be considered satisfactory if the main switchboard and each distribution circuit tested separately, with all its final circuits connected but with current-using equipment disconnected, has an insulation resistance not less than the appropriate value given in Table 64.

gkenyon:

AJJewsbury:

Therefore each circuit can pass an insulation test, but the whole board can fail, so what do you do next?

But there is no BS 7671 value for a single circuit to pass/fail - just one for the complete DB's worth - 1MΩ*


If the whole DB fails, then it's a fail.


   - Andy.


* for initial verification at least.

 

Regulation 643.2 says nothing about DBs


The requirement is:

643.3.2 The insulation resistance measured with the test voltages indicated in Table 64 shall be considered satisfactory if the main switchboard and each distribution circuit tested separately, with all its final circuits connected but with current-using equipment disconnected, has an insulation resistance not less than the appropriate value given in Table 64.