Very low test readings

[pjb1]

Just finished wiring in a conservatory, Two sockets and a light. Tapped into existing ground floor ringmain using 30ma fcu to feed circuits. Also put fcu with 5A fuse for Lighting circuit.
Reading at Zs for sockets 0.41 & 0.47ohms 10kA
Readings for lighting Zs 2 0.61ohms
R1+R2 sockets 0.01ohms
R1+R2 lighting 0.01ohms
Removed 16mmEarthing Conductor to carry out Ze/pscc test reading was 0.00ohms 10kA.
Tests Carried out using Fluke 1653 Multi tester shorted test lead to zero meter.Should I not be getting higher reading as I've said feed off the ground floor rinmain? which is protected via a 32A 60898 mcb.

 

[Sparky Ninja]

Your zs readings sound fine. Your ze is a little suspicious. I assume this is likely to be a PME system? Is the property built into a grid pylon or something.


Did you retake the ze measurement a few times?

 

[pjb1]

The property is pme, I did try it a couple of times the meter came back with 0.00 each time.
I'm not happy with the R1+R2 readings either.
Will have to go back and do the tests again,got any good excuses why I'll have to go back.


God dam Fluke anybody wanna swap for a megger multi?

 

[Deleted member 9648]

0.01 ohms R1R2 readings cant possibly be correct....you need to check your meter against a known resistance and make sure you are carrying out the test in the correct way.

EDIT....Our posts crossed but you have obviously reached the same conclusion yourself.

 

[pjb1]

Wirepuller
Will test the meter against a Known resistance
Question
Do I test only the radials I've installed from the rcd fcu or do I have to test the existing ring final circuit and add both R1+R2 together?
And the 10kA pscc at the cu seem very high as well Wylex with plugin mcbs

 

[JUD]

Your meter definately sounds dodgy. A Zs of 0.47 should give you a fault current of around 500A not 10kA and an R1 + R2 of 0.01 suggests your ring is just over 2 meters long

 

[pjb1]

Thinking about today, I've tested the sockets in the conservatory as a radial circuit not thinking that the rcd fcu is tied into the existing ringmain. I should have cross connected the lives and cpc's to get a proper R1+R2.
This would give me a more realistic R1+R2, wouldn't you think?

 

[JUD]

When you say you have tested it as a radial, where did you link the line & cpc together, at the CU or at the RCD FCU?

 

[pjb1]

At the consumer unit

 

[Sparky Ninja]

Is this a T&CPC installation?

 

[pjb1]

Is this a T&CPC installation?

Not clear what this is?

The installation is a domestic pme supplied

 

[Sparky Ninja]

Did you use this stuff...

 

[pjb1]

Yes I've used that stuff twin&earth. Sorry to be 17th edt correct t&pe

 

[pjb1]

Returned to test again today.Much more realistic results

Ze result 0.14 ohms/1.8kA
Zs at socket in conservatory 0.64ohms

Multi having a bad day just like it's owner