Testing Zs of a circuit

[LearnerSPARK]

Testing Zs of a circuit would be-

Going to the last/furthest point of a circuit and with a two probe tester testing between P and E

Correct????

(This is for an exam)

 

[securespark]

Or mid-point of a ring.

 

[LearnerSPARK]

Thanks mate

 

[dingbat]

Testing Zs of a circuit would be-

Going to the last/furthest point of a circuit and with a two probe tester testing between P and E

You need to test at every point.

The value you record is the highest, which may not be at the furthest point - this is often the case with two-way switching arrangements.

 

[ColJack]

and no, it's a 3 lead tester..

live, neutral and earth..

or at least mine is.. has a handy plug for sockets too..

son of a bitch, it's only 2 lead in the guidance note 3.. might have messed that question up then... but mine DOES have 3..

 

[sparkyspike]

Depends what machine you use. My Megger has 2, and my Fluke has 3 (and won't work on 2)

 

[RF Lighting]

My metrel tester has 3 leads, but you can piggy back the N&E leads for two probe testing

 

[securespark]

So does mine. Good old Alphatek....

 

[Lectrician]

Depends what machine you use. My Megger has 2, and my Fluke has 3 (and won't work on 2)

It will work on two! Either parallel the blue and green, just use the red and blue and press the F1 button to perform the test from live to neutral. You must do this to get the highest PSC - L to E or L to N or P to P

 

[ColJack]

an earth loop tester will not give you PSC...

 

[Spark123]

I don't follow, my loop tester will display PEFC and PSSC values depending on how it is set??

 

[dingbat]

an earth loop tester will not give you PSC...

Semantics!

You do have to do a phase/neutral loop impedance test to get PSCC, but it's all done with the same kit!.

 

[ColJack]

it will give you loop values which you can then use to CALCULATE the PSC, but a dedicated PSC tester ( or multi function tester with it on ) will give you the KA reading.

since my meter is a 3 lead, how do i connect it to do a phase neutral loop?
just hook the black and green leads both to neutral..

 

[Lectrician]

Yes, as stated above - put the E and N to N.

Most digital (if not all) earth loop meters will also give a PFC reading.

 

[didthathurt]

If you think about it, on a PME supply you put the leads to Phase Neutral and Earth, as it's PME you're actually putting the N and E leads to the same point, ie the Neutral, so the Ze and the PSC become the same.