Ze, ZS, R1 And r2 ( 2 part question)

[telectrix]

TBH, i take readings with main earth connected and disconnected, then record the highest reading. there is some dispute with the 1552 as to which

 

[Jimmy Boy]

TBH, i take readings with main earth connected and disconnected, then record the highest reading. there is some dispute with the 1552 as to which

Eh ? Ze ?

 

[telectrix]

yeah, some on here advise to measure Ze with main earth connected using 1552. i am wondering why. tthat is why i do both. only takes a min. also, some advise to read on no trip if Zs has been measured on no trip, apparently so as to get comparative readings. i have only recently acquired the 1552, my seaward having died the other month.

 

[Jimmy Boy]

Eh ?

It's Ze ? installation locked off, isolated ? It's external Impedance ? Has someone lost their regs book ?

 

[telectrix]

steve, you have mis read my post. i am talking about installation isolated at main switch. Ze measurement. normally, dis. main earth from CU and test. however, more than one post on here has suggested leaving the earth connected when testing with a 1552. i can't figure out why, so have recently done a couple of tests with earth in and earth out to see if there is an appreciable difference. going to contact megger to confirm or disprove, as i have always understood the effect of parallel paths, i have only recently acquired the 1552, having, up till now having been used to seaward without no-trip facility. was a pain linking out RCDs with that one.

 

[Jimmy Boy]

Update us soon then mate

 

[telectrix]

might be a day or 2. have a couple of rush jobs beginning of week and then got to plan visits to replace MCBs on about 12 sites ( electrium recall)