metrel mi3000 testing for ze

[Kelrich]

evening everyone
Iam doing some testing and ive done my IR test, continuity of protective conductors, continuity of rfc and a earth fault loop impedance no problems but my metrel mi3000 wont allow me to test for Ze anybody know what settings it should be, am testing a domestic split load consumer unit.
thanks in advance

 

[Deleted member 26818]

You switch the left hand rotary switch to Loop Uc, connect the 3 test leads, make sure it's not set to 'RCD' and test away.

 

[Kelrich]

alright spinlondon

i have tried all this and no joy, ive turned the dial to loop and my options on screen are: Zs, or Zsrcd. I have tried both of these and still no joy, ive even been on the Metrel website and their screen shows loop where my screen shows the above and there is no function to change it.

 

[Guest123]

Are you on a TT system???

Many testers wont allow you to carry out the Ze test if your earth path is overly poor where the touch voltage of 50V would be exceeded when the test was carried out.

 

[Deleted member 26818]

It should show Z loop or Z loop (RCD).
Perhaps yours shows Zs and Zs (RCD) instead.
Either way, Ze and Zs are the same test, just one is conducted at the origin of the installation, with the earth conductor disconnected from the installation, and the other at the end of circuits.

Lenny, the OP says they've conducted the EFLI test with no problems, so there should be nothing preventing them conducting the same test at the origin of the installation.
It's most likely that they are placing the probes on the load side of the main switch.

 

[Kelrich]

Basically i removed the main earth from the earthing bar and attached my green croc clip to it, then placed my brown croc clip to the supply line and my blue croc clip to the supply neutral i then put my meter onto loop, the screen reads Zs or Zsrcd. I pressed test on both of these settings and got nothing so i removed both the brown and blue croc clips and changed them to the probes and placed these probes onto the line and neutral terminals on the main supply switch and again got nothing. Where am i going wrong??????????grrrrr!

 

[esc]

Hi kelrich, i have a similar prob with a friends installation, i put the post on yesterday "this is odd". I can get a Zs from a SO, but when i try get a Ze, meter wont test. I have a metrel similar to yours and it has a display giving PD between L & N and L & E prior to test. The readings i get are very odd. Thought it might be leads, but they're ok.
Theres some views on the post that marry up somewhat with lenny's above and others. Av a look.

 

[Deleted member 26818]

Have you got the main switch off?
Does the meter show a tick to test, or a cross?

 

[cakey]

Turn of main switch.
Disconnect main earth conductor.
Switch to LINE!!
Metrel requires 3 lead test so connect blue and green of test lead together with croc clip onto earth conductor.
Connect Brown test probe to supply line on main switch and test.

Was told loop was for zs test and line for ze. Bit odd but that's the French for you. Always worked for me.... Good luck

 

[Deleted member 26818]

Line is for testing PSCC, not PEFC or Ze, and the test should be conducted with the earth conductor re-connected.
Both are 3 lead tests, all 3 leads should be connected to there respective conductors, you should not connect the blue and green leads together.
You should test both to obtain PFC.
Metrel are Latvian not French.
Here's a link to the instructionmanual: http://www.metrel.co.uk/fileadmin/B...otestEasi_PLUS_UK_HW_3_Ver_1.1_20_751_466.pdf

 

[cakey]

Brilliant spinlondon. That's main earth removed for ze test and connected for pfc and pscc....

 

[Guest123]

Lenny, the OP says they've conducted the EFLI test with no problems, so there should be nothing preventing them conducting the same test at the origin of the installation.
It's most likely that they are placing the probes on the load side of the main switch.

If he has successfully conducted a Zs measurement, the reading may have been obtained via parallel paths. Obviously with the Ze, it's MEC disconnected so as I said there MAY be an issue with the earthing system to the property.

 

[Kelrich]

alright lads thanks very much for the helpful replies.
i have tried the same test in my own house as well as my grandads house and i get the same, nothing no tick or an X onthe screen its like it dosent want to know, like i said on the metrel website they diagrams show the wording LOOP on screen where as mine shows Ze or Zercd. my readings are as follows;

continuity of circuit protective conductors
highest result = 0.6 ohms

IR test
L-N = 1000 ohms
L-E = 1000 ohms
N-E = 1000 ohms

continuity of rfc
R1 = 0.2
R2 = 0.2
RN = 0.3
R1+R2 = 27.9 furthest socket from cu
R1+RN = 0.1 furthest socket from cu

LIVE TESTS
EARTH FAULT LOOP IMPEDANCE zs
used my plug in test lead
reading of 0.44 ohms

LINE IMPEDANCE
used my plug in test lead
reading of 0.29 ohms

PROSPECTIVE FAULT CURRENT
800A

VOLTAGE AND FREQUENCY
U1- L-N= 241V
U1+PE- L+E= 241V
UN-PE- N+E= 0V
FREQ= 50.1HZ
bear in mind Iam just a beginner and I have alot more testing to do but these all seemed ok.
also main earth (16mm) renewed and gas and water (10mm) also renewed and the system is a tnc, am i right in thinking that the Ze reading must go on test cert if yes how on earth am i meant to get it when meter wont play.
any help would be greatly appriciated thanks

 

[Deleted member 26818]

Have you tried to conduct a Zs test using the probes, say at the back of a socket-outlet, or at a light fitting, rather than using the 3pin plug lead?
Just wondering if there's a fault on your probe leads.
To be honest with you, the only things I can think of, is that either there is a problem with your leads, or you are placing the probes incorrectly, perhaps on the load side of the main switch, rather than on the supply side.

 

[Kelrich]

cheers spinlondon
I will try this when i get home and let you know the outcome, i thought maybe it was me not setting the meter correctly but ive followed the exact procedure that metrel use on the website only difference is the screen, also i definatly placed the probes onto supply, its crazy when everything else seems to be working

 

[Guest123]

continuity of rfc
R1 = 0.2
R2 = 0.2
RN = 0.3
R1+R2 = 27.9 furthest socket from cu
R1+RN = 0.1 furthest socket from cu

Could you explain how you obtained these reading a bit more please,.....they really don't add up at all????

 

[Kelrich]

Sorry lenny ive given you the wrong readings there i,ll get back to you tomorrow as i am out at the moment

 

[Kelrich]

Alright lads
lenny ive popped back to re do the rfc test and got practically the same readings
R1=0.2
R2=0.2
RN=0,1
then connected incoming line to outgoing earth and outgoing line to incoming earth
R1+R2= 29.9 fail
then changed my earths to the neutrals and got
R1+RN= 0.0
any ideas whats up and do i have to rectify the problem for my cu assessment?

 

[Octopus]

Alright lads
lenny ive popped back to re do the rfc test and got practically the same readings
R1=0.2
R2=0.2
RN=0,1
then connected incoming line to outgoing earth and outgoing line to incoming earth
R1+R2= 29.9 fail
then changed my earths to the neutrals and got
R1+RN= 0.0
any ideas whats up and do i have to rectify the problem for my cu assessment?

Are you sure you have the ends of the ring correctly identified?

 

[Deleted member 26818]

Alright lads
lenny ive popped back to re do the rfc test and got practically the same readings
R1=0.2
R2=0.2
RN=0,1
then connected incoming line to outgoing earth and outgoing line to incoming earth
R1+R2= 29.9 fail
then changed my earths to the neutrals and got
R1+RN= 0.0
any ideas whats up and do i have to rectify the problem for my cu assessment?

It sounds to me that at one of the socket-outlets the CPC and neutral are swopped over.