testing issues

[jbrown1989]

hello all, im a jib graded electrician just finished my 2392 course and have my 2391 course booked for the end of september. im pretty as green as grass as testing goes as i have not a great deal of experence. ive be asked to test a number of circuits and the sockets all have metal back boxes and are all earthed, making my r1 and r2 tests a nightmare because it is not practible to disconnect all fly leads conneting the earth to the backboxes to the steel and so on. i have got ok reading on the zs tests at each socket and measured the live to live neutral to neutal and earth to earth values on the dead tests. also ok readings on rcd tripping, and insulation resistance. so to sum it all up i havent got a correct value fo the r1 and r2 figure of eight loop on the dead tests. is this a problem? do i have to dissconnet ALL flyleads and possible parrell paths?


ps sorry im not that great at explaning things

 

[telectrix]

you do not need to dis the flyleads. just cross connect the L and E 's at the CU and get your R1+R2 readings from each point. ( notice the use of caps. R1 and r1 are completely different values)

 

[Deleted member 26818]

If this is not an initial certification, R1+R2 is not required, just Zs.
If it is an initial certification, the fly leads will be required to be dsconnected, and R1+R2 will have to be measured and recorded.

 

[cbw]

Nice name!

 

[jbrown1989]

cheers all

 

[jbrown1989]

ok thanks for the reply, by cross connect do you mean the figure of 8 loop method? ive tried that method by cross connecting the opposite legs, then i try on the same legs and still seem to get the same reading at each socket, is this due to parallel paths?

 

[telectrix]

you should get tha same readings at each socket. it's because it's cross connected ( figure8 ). only time your readings will be higher is if you've got a spur or a poor connection.

 

[SirKit Breaker]

If you are a bit green with testing and you are doing the 2391 this month then getting GN3 now and getting stuck in is a must. The more of GN3 you can digest the easier it will be. As for the practical don't dwell too much you will be walked through it during the course, but a good read and study of the test procedures will stand you in good stead.

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

 

[ezzzekiel]

be carefull of taking the readings from the sockets on older installs the readings can often vary, best to check at the terminals sometimes

 

[Deleted member 26818]

Then you can also check the terminals are tight, that earth sleeving is present and that there are no problems with corrosion through rising damp.