Continuity of cpc's R1+R2

[sparko]

Hi guys, when testing continuity of cpc's r1+r2 method, with main switch isolated, can you link from the live bus bar to the main earth bar in the C.U with a small croc clip and just turn mcb on for the circuit under test? If not at which exact point would you link the line and earth in the C.U?

 

[Guest123]

Hi guys, when testing continuity of cpc's r1+r2 method, with main switch isolated, can you link from the live bus bar to the main earth bar in the C.U with a small croc clip and just turn mcb on for the circuit under test?

Yes. This also confirms the MCB is sound.

See pic advertising the leads you describe and their use.....Ignore the fact that ALL MCB's and the RCD is switched on!!

 

[Jimmy Boy]

Just have the wire out the breaker and the CPC out the Earthing terminal and chocky them together, if it's a ring you will have to have them all out anyway as the first step of ring final circuit test is end to end resistances of L/N/E start as you mean to go on

 

[Amp David]

Out of the MCBand earth bar them use those jump leads which are pretty good

 

[telectrix]

i very often us an alternative method. breakout box in socket and link L/E or N/E, then test at CU. move box to each socket in turn and record highest reading. have to remember to remove link before energising though.

 

[BigBreakfast]

I prefer this method too using the link between bus bar and earth and as Lenny says this proves the mcb and saves a good bit of time regarding disconnecting ends etc.

 

[telectrix]

but should the internal resistance of the MCB be included in R1+R2?

 

[BigBreakfast]

but should the internal resistance of the MCB be included in R1+R2?

Wondered the very same thing when first adopting this method, but could find little if any difference in any circuit that I would test using both methods so far.

 

[andyb]

Ignore the fact that ALL MCB's and the RCD is switched on!!

I imagine that the main switch is off, I'm more interested in what is being tested as there seems to be no circuits in the mcbs.

 

[telectrix]

think Lenny was showing the pic for illustration purposes.

 

[Guest123]

but should the internal resistance of the MCB be included in R1+R2?

Well technically there shouldn't be any of any note and if there was this should highlight the problem. The only other reference to MCB soundness is Zs but as a lot of people prefer to calculate, we're only left with this.

All IMO.

 

[Deleted member 9648]

The only thing that bothers me with the link to busbar method is forgetting to remove it before switching on........shouldnt happen I know, but it's late on a friday and you are almost done....you know how it is....BIG BANG....I'd want a fused link.

 

[Guest123]

The only thing that bothers me with the link to busbar method is forgetting to remove it before switching on........shouldnt happen I know, but it's late on a friday and you are almost done....you know how it is....BIG BANG

Only too well!!!!!!!!!


To be fair it was in my mis spent youth when all that mattered was alchohol intake.

 

[Jimmy Boy]

Would any of the methods noted be acceptable methods for an NICEIC annual reassessment ?

ATB Steve

 

[Jimmy Boy]

A fused link could add substantial resistance to the measurement