Installation resistance of 0.39Mohms n -e

[Sparky92]

Hi all,

I was testing a property yesterday, and had a a very low resistance between neutral and cpc, it was 0.39Mohms, between live and earth = 500Mohms and live and neutral 398Mohms. Iv unplugged everything and took all sockets down to see if n and cpc was touching but could not see anything. Could someone please let me know what could cause and how to find the fault?

Regards

jim

 

[Octopus]

What do you plan to do next?

 

[telectrix]

split the circuit and track the low reading down, splitting again and again till you locate it. a good idea is to disconnect anything that goes outside first and ensure there's nothing plugged into hidden sockets/FCUs. BTW< is it a socket cicuit/lighting circuit/ other?

 

[Sparky92]

It's a socket circuit.

 

[Sharpend]

Follow procedures as outlined in GN3.

 

[HappyHippyDad]

Hi all,

I was testing a property yesterday, and had a a very low resistance between neutral and cpc, it was 0.39Mohms, between live and earth = 500Mohms and live and neutral 398Mohms. Iv unplugged everything and took all sockets down to see if n and cpc was touching but could not see anything. Could someone please let me know what could cause and how to find the fault?

Regards

jim

Good luck Jim! Lucky you didn't find this after a CU change .

This is something I need alot of practise on too!! I had a 0 MΩ N-E and split the ring and eventually after 3 hrs found a box screw just slightly bitten inro the neutral!! The point is I dont think you would have a reading of any ohms if they were actually touching, a part from that I cant be of any more help. I also dont see how it could be anything plugged in if your L-N is ok!!

 

[telectrix]

Tel, you are not helping. For this forum to help people we need them to offer up their ideas first.

If we just charge in with answers people won't learn to think for themselves.

well, my comment was only a logical suggestion. he'll still need to use his head to locate the problem.

 

[Sparky92]

Could I just plug the plug in lead in to every socket intill I get 0Mohms, as there is a load of junk everywhere, bed in the way and all the stuff from the loft in rooms. Iv taken most of the sockets down i could physically get too. Would this help me find the the fault or not?

Cheers

 

[Octopus]

well, my comment was only a logical suggestion. he'll still need to use his head to locate the problem.

I know but so many come on here asking questions yet not demonstrating any ideas about how to approach things!!

 

[telectrix]

Could I just plug the plug in lead in to every socket intill I get 0Mohms, as there is a load of junk everywhere, bed in the way and all the stuff from the loft in rooms. Iv taken most of the sockets down i could physically get too. Would this help me find the the fault or not?

Cheers

why would you expect to get a reading of 0 ohms? think a bit.

 

[telectrix]

I know but so many come on here asking questions yet not demonstrating any ideas about how to approach things!!

yep. sometimes difficult to draw the line between helping and spoon feeding.

 

[Sparky92]

To indicate where the fault is. Im not going to lie this is my first time fault finding.

 

[Octopus]

Could I just plug the plug in lead in to every socket intill I get 0Mohms, as there is a load of junk everywhere, bed in the way and all the stuff from the loft in rooms. Iv taken most of the sockets down i could physically get too. Would this help me find the the fault or not?

Cheers

I thought you said you'd unplugged EVERYTHING. Clearly you may not have.

First rule - retrace ring and make sure everything IS unplugged.

 

[telectrix]

hint. fridge/freezers. hidden sockets.

 

[iamelectric]

what appliances would give N-E reading like his

 

[Guitarist]

To indicate where the fault is. Im not going to lie this is my first time fault finding.

So, are you charging this customer for something which you have no experience or knowledge in?

 

[iamelectric]

^^^^^ shut up , if your not going to help the guy then don't comment , hes being honest and learning as he goes

 

[derek preece]

Follow Tel's advice in post 3 with your IR tester, best to test at 250v if you're not sure if you have disconnected everything. I'm surprised that you are 4th year apprentice and haven't done any fault finding.

 

[Guitarist]

^^^^^ shut up , if your not going to help the guy then don't comment , hes being honest and learning as he goes

Don't tell me to shut up! This is what's wrong with the trade now. People like you think that it's ok to tackle jobs without any training or experience at all, just because the person is "being honest".

 

[derek preece]

^^^^^ shut up , if your not going to help the guy then don't comment , hes being honest and learning as he goes

I'm thinking of becoming gas safe registered so can I come and work on your boiler (I don't want to work on mine in case I break it) I'll charge you for the inconvenience as well

 

[iamelectric]

I am interested in this thread as i don't have a lot of experience in testing either , i dont want to read thru pages and pages of people telling the guy he needs this and that and he shouldnt be doing it , am sure hes heard it all before on here , if u want to write all that crap start your own thread about it , otherwise read his first post and answer the question

 

[Dcf]

Whatever next! specialist fault finding teams to bail out all the "sparks"who don't know how to fault find?
fault finding is a basic part of electrical work that has to be taught .you don't get it in a book or on the Internet.
it takes years to get proficient in quick fault diagnosis IMO.
Learning on the hoof and tring to blag your way out of it is not gonna happen.
some of the threads on here recently really boil my Pish with the complete lack of knowledge of even the basics
and then getting huffy when they get found out for the roasters that they are.

 

[telectrix]

question has been answered . advice has been posted. other than going there to do the job--- he has to put in the effort himself.

 

[iamelectric]

fair enough tel but theres no need for all the negative comments , if you dont want to help the guy then dont comment , simple as that

 

[Geordie Spark]

What do you plan to do next?

If I was him I would go back to school to learn the difference between the words "installation" and "insulation".