Insulation resistance 0.00megger ohm

I went to a smart home today; the client said the main rcd keeps tripping, so I opened the CU and done a IR. Switched mcbs off and located the earths for the kitchen ring and got 0.00meg ohm between L-E.

As I know; new regs, it's 1meg min for 230v, so I located the neutral and the same reading from the out going line conductors to the separated neutral conductors from the common neutral bar as this is indicating a dead short.

Why does the mcb not trip and the rcd only trips every now and then? Is it because 500v is a higher presure test than 230v? There was 3 other circuits on this fuse board like this, I'm not used to working in a smart home any ideas people?

Also the CU used to be in the kitchen and the consumer unit was moved to upstairs and the client said all the joints are behind the wall and plastered over. I think there is a cable crushed somewhere or a bad joint behind that wall.

The client said put rcbos in to see what one trips then we will narrow it Down, but I said to the client there is a problem with the wiring with the insullation resistance, the client is an electronic engineer so he said just do that. T

Thanks for your help people.

I went to a smart home today the client said the main rcd keeps tripping so I opened the CU and done a IR swiched mcbs off and located the earths for the kitchen ring and got 0.00meg ohm between L-E as I know new regs it's 1meg min for 230v so I located the neutral and the same reading from the out going line conductors to the separated neutral conductors from the common neutral bar as this is indicating a dead short why does the mcb not trip and the rcd only trips every now and then is it because 500v is a higher presure test than 230 there was 3 other circuits on this fuse board like this I'm not used to working in a smart home any ideas people? Also the CU used to be in the kitchen and the consumer unit was moved to upstairs and the client said all the joints are behind the wall and plastered over I think there is a cable crushed somewhere or a bad joint behind that wall. The client said put rcbos in to see what one trips then we will narrow it Down but I said to the client there is a problem with the wireing with the insullation resistance the client is an electronic engineer so he said just do that. thanks for your help people

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headbang

0.00Meg ohms is NOT a dead short..

0.00ohms is a dead short...

1.0Megohms = 1,000,000 ohms

9,999ohms OR 9.99kohms would show as 0.00Meg ohms....

i.e. 0,009,999 ohms!

what chance does the trade stand when people don't even know the basics of their meter scale..

230v/32a = 7.18ohms so even 7 ohms wont tip your MCB..

6ohms is the load of your typical domestic shower

this would show as 0.00Meg ohms NOT a dead short...

when I went to college this was basic electrical science.. perhaps the don't teach it anymore!! :_|

Punctuation can be your friend..... :innocent

I have had to read that about 5 times and it still is as clear as mud, mind you I have been hammering the Merlot......... :coat

Punctuation can be your friend..... :innocent I have had to read that about 5 times and it still is as clear as mud, mind you I have been hammering the Merlot......... :coat

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I'll tell you what, I've not had a drop and I still can't follow it:O

I'll tell you what, I've not had a drop and I still can't follow it:O

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Its a house made of Smarties and the kitchen used to be inside the CU till the 500v pressure forced it through the plastered wall....

And he's got a crush on the electronics engineer!

I think?????

GuinnessGuinnessGuinnessGuinnessGuinnessGuinness

It all makes sense now

Might get me in bother, but I don`t care................................. X(

Its got sod all to do with it being a smart house - more the intellectual ability of the tester isn`t smart enough, I`m afraid. headbang

I didn`t understand a lot of the nonsense in your post - but the bit I did get says that you aren`t competent to be using a screwdriver! :C

Sorry - I don`t intentionally cause offence, but FFS!!!!! Basic first year student should know this - and you`re charging people to do this!!!!! :red card

Why the heck did the rest of us bother to learn anything at all? headbang

Oh, nearly forgot. The answer to your problem? Get an electrician in. :good luck:

Two obvious questions for the OP:

you DID unplug EVERYTHING (and I mean everything) from the ring before testing didn't you? and that includes the built in dishwasher etc.

And you DID disconnect the neutral from that circuit from the neutral bar didn't you?

The client said put rcbos in to see what one trips then we will narrow it Down

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or you could learn how to use your test kit and it will tell you what circuit the problem is, in a lot less time than it would take to install any RCBO's

and maybe you should have mentioned to your client, the 'electronics enginner' that 0.00meg is a dead short. maybe he could have pointed out the basics for you before you left... (wih the added benefit that he would know you dont have a clue and to get someone else)

Question to the OP :

a) Have you had ANY training in the domestic electrical sector?

and if so,

B) Did you miss the last 4 days of your 5 day course?

On the positive side, I`m amassing a wonderful body of anecdotal evidence for the Ricoh and the Select Committee .... cheers to the OP!

I joined the forum back in 2008. For nearly 4 years I have been absent from the forum and spent most of my time on screwfix. I have come back to this forum because I got sick of the screwfix smart alecs and insidious postings. I recognise many members awho also used to post on screwfix and it is nice to see them all. Unfortunately I brought my bad habits with me and name called someone on here. For that I received an infraction, received 10 points, had three mods and an admin after my blood. To be honest it shook me up! Now, I did not enjoy reading this post. It smacks of double standards. Some of you guys have ripped the OP to shreds. Do you really think it is necessary to respond to a poster in this manner? You appear to get away with it because you are long established members. But, think about how you have treated the OP. It is not nice. I'd be surprised if the poor bloke ever returns again. Shame on you. Some of you have made out it is basic stuff. It wasn't to Nick and I feel it was out of order the way you all ripped in to him. I have said my piece. Any comments Admin? Pro Dave gave the only helpful reply.

I joined the forum back in 2008. For nearly 4 years I have been absent from the forum and spent most of my time on screwfix. I have come back to this forum because I got sick of the screwfix smart alecs and insidious postings. I recognise many members awho also used to post on screwfix and it is nice to see them all. Unfortunately I brought my bad habits with me and name called someone on here. For that I received an infraction, received 10 points, had three mods and an admin after my blood. To be honest it shook me up! Now, I did not enjoy reading this post. It smacks of double standards. Some of you guys have ripped the OP to shreds. Do you really think it is necessary to respond to a poster in this manner? You appear to get away with it because you are long established members. But, think about how you have treated the OP. It is not nice. I'd be surprised if the poor bloke ever returns again. Shame on you. Some of you have made out it is basic stuff. It wasn't to Nick and I feel it was out of order the way you all ripped in to him. I have said my piece. Any comments Admin? Pro Dave gave the only helpful reply.

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its obvious he is way out of his depth and shouldnt be doing the 'work' he is 'attempting' to do. which is why the got the answers he did.

Scoob for unphased well said

Andy you have missed my point. There are far too many judge and jury responses. With the greatest of respect, Andy, who are you to decide whether he is out of his depth? Your post did nothing more than add to what was already damaged.

Andy you have missed my point. There are far too many judge and jury responses. With the greatest of respect, Andy, who are you to decide whether he is out of his depth? Your post did nothing more than add to what was already damaged.

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the fact he doesnt know how to use his test kit is a good point that he shouldnt be doing that kind of work yet. for all i know he could be very good at installation work, but not this. especially being paid to do it, and then coming up with the suggestion of installing RCBO's to narrow it down. if he had more experience / practice of using his test kit, and how to understand what its telling you, then he would have been able to indetify the faulty circuit within minutes, and from the readings, be able to take a guess as to what the fault may be, and where to start looking.

no idea how qualified or what courses he's done, but i would guess a short course thats only designed to teach you enough to pass a test with little / no real world experience

May be there should be a dislike button. For people who are insulting.

That is not a bad idea, samson. ; \

Totally agree Samson

Totally agree Samson

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cant say im surprised at that...

I joined the forum back in 2008. For nearly 4 years I have been absent from the forum and spent most of my time on screwfix. I have come back to this forum because I got sick of the screwfix smart alecs and insidious postings. I recognise many members awho also used to post on screwfix and it is nice to see them all. Unfortunately I brought my bad habits with me and name called someone on here. For that I received an infraction, received 10 points, had three mods and an admin after my blood. To be honest it shook me up! Now, I did not enjoy reading this post. It smacks of double standards. Some of you guys have ripped the OP to shreds. Do you really think it is necessary to respond to a poster in this manner? You appear to get away with it because you are long established members. But, think about how you have treated the OP. It is not nice. I'd be surprised if the poor bloke ever returns again. Shame on you. Some of you have made out it is basic stuff. It wasn't to Nick and I feel it was out of order the way you all ripped in to him. I have said my piece. Any comments Admin? Pro Dave gave the only helpful reply.

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You have to remember that some people are out there doing electrical work that is far above their knowledge, this puts Part P of the building regulations into question, and puts the whole of the electrical installation trade in bad light.

Had the OP phrased the question differently it may have had a better response. Being competent you must have full knowledge and skill to do all of the work that you are being paid to do.

Trading without those core skills is borderline fraudulent. If I had encountered those reading during any test I would know instantly what was or is a possible cause, and gone on to rectify it.

So do not get defensive for those who are out there doing really bad work and getting paid for it.

If any post is not to your liking you can report that post and the Admin team will deal with it as they see fit, by discussion and agreement. No member is immune to infractions as some of our longer members can attest. Even I am not immune so I doubt any member would be either.