Continuity / Ohms testing help / Short ?

[king185]

Hi,
I would love some help understanding an issue I’m having on a 16mm SWA cable running from the CU in my house to the CU in the shed.
I believe there is a problem with the cable (possibly between E and N), and I have used a multi-meter to do some checks on the CU (shed side) and below you will see my finding.
Please note that the tests are done whilst the MCB in the house is OFF so there is no voltage at the shed whilst performing these tests, however the cables are still connected at the CU in the house (shed ones are disconnected).


https://1drv.ms/i/s!AicNdL7JWhGahawkCq1gV5yjwZM3uA?e=UoM1WT
https://1drv.ms/i/s!AicNdL7JWhGahawj2CAfR9zxn-Pi5g?e=Obqlme
I think my electric supply coming into my house is TN-S. I will attach a 2 photos above so someone might be able to confirm this.
Also to note i did a continuity test between the earth bar and the neutral bar in my CU in the house and we have a LOUD BEEP.


https://1drv.ms/i/s!AicNdL7JWhGahawcNYe4hV-GacO3cA?e=2mzlCy
Above is common (black cable from multi-meter) connected to N and red cable connected to E.
Multi-meter is in AUTO MODE set to OHMS and we get 2.1 ohms.


https://1drv.ms/i/s!AicNdL7JWhGahawWWt91uVD49sVKiA?e=w6s24B
Above is common (black cable from multi-meter) connected to N and red cable connected to E.
Multi-meter is in IN MANUAL MODE set to OHMS and we get 3.9 ohms.


https://1drv.ms/i/s!AicNdL7JWhGahawbWsXbg4qcmA6VaA?e=ZHEvAA
Above is common (black cable from multi-meter) connected to N and red cable connected to E.
Multi-meter is in CONTINUITY MODE and we get a LOUD BEEP with a reading of 7.9 (is this ohms?) – I do not know what this means.
But I do understand that there is a pathway between N and E which seems like that maybe the fault.


https://1drv.ms/i/s!AicNdL7JWhGahawU1iw4AK0u4_8v0w?e=Tt1fWV
Above is common (black cable from multi-meter) connected to E and red cable connected to N (notice I switched the cables around to see if it makes a difference).
Multi-meter is in IN MANUAL MODE set to OHMS and we get 0.0 ohms
This occurs again even in AUTO MODE (no photo for this) for ohms it gives a straight 0.00 instead of OPEN LINE.
I find this strange, but I don’t know why. Haha.


https://1drv.ms/i/s!AicNdL7JWhGahawS2aPPBwa4Fi_ynA?e=PRyDnv
Above is common (black cable from multi-meter) connected to E and red cable connected to N (notice I switched the cables around to see if it makes a difference).
Multi-meter is in CONTINUITY MODE and we get a LOUD BEEP AGAIN with a reading of 4.5 (is this ohms?) – AGAIN I do not know what this means. But I think something is wrong.


https://1drv.ms/i/s!AicNdL7JWhGahawZYfAcD4saxhHRFg?e=I0nULJ
Above is common (black cable from multi-meter) connected to N and red cable connected to L.
Multi-meter is in AUTO MODE set to OHMS and we get 5.063 M ohms.
I think this is MEGA ohms and I don’t understand if this is normal, I think this is normal.


https://1drv.ms/i/s!AicNdL7JWhGahawY10VSgWlnTrBv2A?e=YIOnj9
Above is common (black cable from multi-meter) connected to N and red cable connected to L.
Multi-meter is in IN MANUAL MODE set to OHMS and we get OPEN LINE.
I don’t understand why there is a difference between AUTO MODE showing over 5 MEGA ohms and this manual mode showing OPEN LINE, but I think this is GOOD and normal.


https://1drv.ms/i/s!AicNdL7JWhGahawaIPdmInzCpcFK1g?e=SGCVQc
Above is common (black cable from multi-meter) connected to N and red cable connected to L.
Multi-meter is in CONTINUITY MODE and we get a NO BEEP with a reading of OPEN LINE.
This looks OK to me.


https://1drv.ms/i/s!AicNdL7JWhGahawXMPHXIuM7a3eoDg?e=H2dJy1
Above is common (black cable from multi-meter) connected to E and red cable connected to L.
Multi-meter is in AUTO MODE set to OHMS and we get 5.99 M ohms.
Again I am not sure if this is normal.


https://1drv.ms/i/s!AicNdL7JWhGahawTQTuFMqUuID58Hg?e=D68YO2
Above is common (black cable from multi-meter) connected to E and red cable connected to L.
Multi-meter is in IN MANUAL MODE set to OHMS and we get OPEN LINE.
I think this is GOOD.


https://1drv.ms/i/s!AicNdL7JWhGahawVl-ZTh4bCmK7H8A?e=XHN1Mq
Above is common (black cable from multi-meter) connected to E and red cable connected to L.
Multi-meter is in CONTINUITY MODE and we get a NO BEEP with a reading of OPEN LINE.
This looks OK to me.


Does anyone have any thoughts as to what is going on?
Do you think I should do further tests or is it simple to say there is a NEUTRAL to EARTH fault on my 16mm2 SWA cable?

Help will be much appreciated.

Kind regards.

 

[king185]

Some more information.

I probably dont need 100 amps with a 1000v cable at the moment, but i want to replace like for like, and future proof it, also if i ever get the shed extended or build a back room in the garden its good to have the correct cabling.


I dont want to replace the whole cable as alot of the cable goes out and around the house from the front then comes out at the rear in the corner of the house then makes its way down into the ground and covers a distance of about 20-35m meters to the shed.
The plan is to cut it before it goes into the ground and replace approx between 25-35m worth.
All the cable under the ground will be replaced and that should do the trick, and of course it will be tested before its joined up.

The cable was previously damaged only on the outer sheath and a little bit of the earth steel armour was exposed.
This then got patched up with insulation tape and duck tape on top.
(this damaged part will be replaced)

Possible damp ingress and corrosion cannot be ruled out.

The last thing we want is to running around in circles, that is why i am willing to have the underground bit (25-35m) chopped off and replaced!
Surely that will fix the problem.

Also the cable i currently have is 2 core with the armoured steel earth. I will use the same type of cable again, so i will not be spending extra money to buy a 3 core as that is unnecessary.

I can source the cable and joint connectors myself.

Any ideas of how much this should cost and electrician to do? Also how long would it take?

Thanks