ze & zs testing at a consumer unit

[Duane B]

Ok guys & Hi not been on for a while trying to learn new stuff and skills and bring back old ones forgotten, Lol

Question, Ze & Zs testing domestic.

ze Consumer unit main switch off, main earth removed from met, proceed with test, Ze yes, on loop setting

Zs at sole Db consumer unit, main switch on, all rcds breakers etc off. Fluke 1654B 3 lead test  Phase, Neutral, Earth.  placed at main switch energised terminals and earth bar,  is this good enough for Ze as a spark said I needed a designated efli tester.  Though fluke 1654B on hi current is good enough as it tells me both KA value and impedance

Any light on this would be great please guys trying to progress in testing area. but confused from other sparks remarks on sites.

Ta

 

[Andy™]

any loop impedance meter will tell you Ze or Zs. the only difference is where you connct the leads

 

[Rob_the_rich]

The Zs you described is not good enough for a Ze measurement, there might be parallel earth paths, that is why you take the main earth from the MET and test using that, as you described with your Ze test.

Not sure what the other spark means by "designated", perhaps calibrated? The Fluke is an earth fault loop impedance tester.

 

[Duane B]

The Zs you described is not good enough for a Ze measurement, there might be parallel earth paths, that is why you take the main earth from the MET and test using that, as you described with your Ze test.

Not sure what the other spark means by "designated", perhaps calibrated? The Fluke is an earth fault loop impedance tester.

Sorry Ze correct yes. 2nd part I meant Zs "and not good enough for Ze" typo error. sorry. meant. to say:

3 lead test phase. neutral lead off main switch and earth to main bar. all breakers off etc. all bonding in place. fluke on high current. this is how I'm doing a Zs on a db to meter head if it's sealed. 

Cheers 

 

[Rob_the_rich]

For testing Zs at distribution board, leave it switched off at main switch and test at the incoming terminals for L&N (use earth bar for E, all bonding and earthing conductors in place), it is a bit safer than testing at the live busbar and neutral bar, and no need to switch off all breakers. Remember to also do the LN test so that you get the PSSC, compare this with the PFC you got from the Zs measurement and record the highest value.

 

[Duane B]

Awsome. was always told to switch breakers off. but suppose that's was yonks. years ago old training. been out game a bit. suppose way I was testing was ok. but yes I do that with Ln test. thanks for steer in right direction.