Couple of quick ones!

[OhmSweetOhm]

1. Am I right in thinking that when doing an end to end test on the CPCs during a continuity of ring final circuit conductors test, the result divided by 4 gives you R2? But measuring as you will measure R1+R2 anyway, this does not need to be noted?

2. When doing an insulation resistance test on a circuit supplied by an RCBO, the RCBO's earth and neutral must be removed?

3. Where in the regs would I find the tables showing the minimum and maximum readings for continuity and insulation resistance? (I think the table for Earth Fault Loop Impedance is Table 2D Page 103...?)

4. When measuring continuity on a ring which has a socket spurred off from another socket, do I carry out the test in the exact same manner? And if the reading at the spurred socket is the highest reading (which it will be), this is the result I write down?

Thanks for any help on clearing these up!

 

[tony mc]

Hi

You will record the r2 along with the r1 and rn of a final ring circuit you would then record the R1 + R2 on the cert.

Most RCBOs will have a warning on them and yes remove the cables before IR testing as the results could be lower or you might damage the RCBO take the functional earth off as well.

GN 3 page 103 will give you resistance of copper and aluminium conductors. Table 61 gives you the minimum values of insulation resistance.

You would record your highest R1 + R2 which should be at the spur and then you would carry out you ZS at this point.

Hope that helps.