Protective Conductors Continuity

[Piratepete]

Hi Guys and Dolls
In my 2004 edition of the IEE Inspection and Testing Guidance Note 3, page 78, Protective conductor continuity can be confirmed with an Earth fault loop impedence test (R1 + R2 or R2 is not required to be measured). (Note 4)
Ring circuit continuity also does not have to be measured 'Where there are proper records of previous tests and no changes have been made to the ring final circuit'

Is this still allowable under the latest regime for PIRs?
If so, do you rely on a Zs test only?

Pete :winkiss:

 

[mark1979]

R1+R2 is required for initial verification. PIR is now EICR and this is 2012.

 

[rich.250]

I think a new copy of gn3 is in order

 

[telectrix]

IMO, the whole purpose of measuring R1+R2, or R2, is to ensure that the circuit is safe to energise, and that the values are low enough to obtain satisfactory Zs readings.( along with IR testing). when carrying out a PIR/EICR, the installation is already energised so not entirely necessary.

 

[Octopus]

This is a "grey" area (I'm sure others will have opinions) but it would seem that if the EFLI can be confirmed on a radial it would seem pointless to do an R1 + R2 or R2. On a ring final circuit it would be essential as would confirming continuity of all conductors end to end

 

[telectrix]

agree that an end/end test on RFC is necessary, but that can be confirmed by measuring e/e.) r1,r2,rn) without R1+R2.

 

[Deleted member 26818]

Yes protective conductor continuity can still be confirmed by conducting a Zs test.
This test will also prove continuity of the line conductor.
If at the same time you also conduct a PSCC test you will then be proving neutral conductor continuity.
When conducting the Zs test, if you operate any switches, you will be proving the polarity of those switches.

 

[Piratepete]

PIR is now EICR and this is 2012.

Sorry - force of habit - I'll eventually get me tongue around EICR

 

[i=p/u]

its ok we still in transition, take your time, chill

 

[mark1979]

apologies pete...i probably sounded a bit cheeky there!

 

[IQ Electrical]

Sorry - force of habit - I'll eventually get me tongue around EICR

We still carry out a Periodic Inspection but we complete an Electrical Installation Condition Report.

 

[SirKit Breaker]

The other advantage of Zs at each outlet, as well as confirming r1 and r2 continuity, if you do it by plugging in at each outlet, you will confirm polarity.

Cheers............Howard

 

[Brightspark2]

Although when I did my 2391 the tutor advised you do R1+R2 and calculate the Zs rather than Testing Zs and calculating R1+R2. As it was more accurate that way

 

[IQ Electrical]

Although when I did my 2391 the tutor advised you do R1+R2 and calculate the Zs rather than Testing Zs and calculating R1+R2. As it was more accurate that way

Yes, the 'back calculation' (R1+R2) = Zs-Ze is distorted by parallel earth paths and should not be used.

 

[acvc]

Yes, the 'back calculation' (R1+R2) = Zs-Ze is distorted by parallel earth paths and should not be used.

Can anyone give me a few examples of what parallel earths might be there? Thanks. Got the theory, need the practice ......

 

[IQ Electrical]

Can anyone give me a few examples of what parallel earths might be there? Thanks. Got the theory, need the practice ......

Yes, any bonding/supplementary bonding, along with simple cpc connections to items that are bonded by virtue of pipework connections (boilers etc.) right down to luminaires sitting in a conductive ceiling grid.
In all but the most basic 'all-insulated' installations, there are many parallel paths.

 

[Brightspark2]

Yes, the 'back calculation' (R1+R2) = Zs-Ze is distorted by parallel earth paths and should not be used.

Thats the one...


So if people are only testing Zs what do they put in the R1+R2 box on the test sheet? N/A?...

 

[IQ Electrical]

I've seen everything from a tick, N/A, LIM or a back calculated value...

 

[ackbarthestar]

Hi Guys and Dolls
In my 2004 edition of the IEE Inspection and Testing Guidance Note 3, page 78, Protective conductor continuity can be confirmed with an Earth fault loop impedence test (R1 + R2 or R2 is not required to be measured). (Note 4)
Ring circuit continuity also does not have to be measured 'Where there are proper records of previous tests and no changes have been made to the ring final circuit'

Is this still allowable under the latest regime for PIRs?
If so, do you rely on a Zs test only?

Pete :winkiss:

Page 73-74 GN3 5th ed. Cost £25. ------:happy:

 

[pushrod]

Apologies for ressurrecting old thread

Yes, the 'back calculation' (R1+R2) = Zs-Ze is distorted by parallel earth paths and should not be used.

What if doing an inspection (on empty house) and you disconnected main protective bonds and did Zs -would your Zs - Ze = R1+R2?

Seems a lot of hassle when working by yourself to be doing R1+R2 and a Zs at every point when the results don't really show anything new?
(not got access to a GN3 5th ed) Any thoughts?