Parallel paths on R1 + R2 test

[DaveS]

Hi there

Doing some testing at moment. R1 + R2 readings coming in lower than R1 + Rn. Cpc neutral and live all disconnected. There is alot of containment on job and adaptable boxes are all fly leaded to earth. My thoughts are they are parallel earth paths but guy working with seems to think because cpc disconnected at board it can' be. Who is right basically? Thanks

 

[Pete999]

Hi Pete I don' think I can do end to end readings as over multiple floors? The leads were nulled yes. Have just tested a seperate circuit and how similar readings with a 0.30 lower difference again with r1 + r2 this does parallel paths no?

End to end readings are for RFCs, this is where the confusion comes from, if you had mentioned that it was a lighting circuit the confusion would have come to the for earlier, you may need to brush up on your testing procedures Mate, the question begs, how did you get your R2+R2 results?

 

[Pete999]

Hi Pete I don' think I can do end to end readings as over multiple floors? The leads were nulled yes. Have just tested a seperate circuit and how similar readings with a 0.30 lower difference again with r1 + r2 this does parallel paths no?

End to end readings are for RFCs, this is where the confusion comes from, if you had mentioned that it was a lighting circuit the confusion would have come to the for earlier, you may need to brush up on your testing procedures Mate, the question begs, how did you get your R2+R2 results? Message to oneself don't assume anything or that anyone knows what they are doing.

 

[westward10]

Now we know it is a radial then yes any metal containment will affect readings due to parallel paths unless you isolate the cpc from the containment. Disconnecting the cpc at the board will have little effect unless the cpc goes to a single point of utilization.

 

[Pete999]

Now we know it is a radial then yes any metal containment will affect readings due to parallel paths unless you isolate the cpc from the containment. Disconnecting the cpc at the board will have little effect unless the cpc goes to a single point of utilization.

Deleted

 

[MFS Electrical]

Hi there

Doing some testing at moment. R1 + R2 readings coming in lower than R1 + Rn. Cpc neutral and live all disconnected. There is alot of containment on job and adaptable boxes are all fly leaded to earth. My thoughts are they are parallel earth paths but guy working with seems to think because cpc disconnected at board it can' be. Who is right basically? Thanks

There could be parallel paths if the conduits are straight into the board or into trunking and the trunking is bonded and the building structure can also create a parallel path to earth

 

[DaveS]

End to end readings are for RFCs, this is where the confusion comes from, if you had mentioned that it was a lighting circuit the confusion would have come to the for earlier, you may need to brush up on your testing procedures Mate, the question begs, how did you get your R2+R2 results? Message to oneself don't assume anything or that anyone knows what they are doing.

 

[DaveS]

Thank you to everyone for replys. Should of probably clarified it was a lighting circuit

 

[Deleted account]

Having read the entire thread again I think your mate is not correct and you are.