Unexpected Reading Between Earth And Neutral

[steptoe]

Get some beers in and a couple of dancing girls and I'll come round,

 

[not_shocked_yet]

Canoe, Lol.  I'm also restoring a  25 ft 1938 Robert Clark sloop, do stop by at any time!

Noz and Canoe - you cant pay for experience, no matter what it costs!  I would happily pay.  And if steptoe only wants girls and beer then that is easy to arrange.

My day was Raffles.

 

[not_shocked_yet]

Deal, will PM you on Monday.

 

[Rob_the_rich]

Hi not_shocked_yet, did you see my post #32, there were 5 of us posting at 10.26pm that day so you might have missed it.

Good luck with the testing.

 

[not_shocked_yet]

Hi Rob_the_rich,

""  It must be something in the house which is giving you that voltage, possibly electronics. You could switch all the breakers off and test the main switch outlet points again for voltage to earth, then test each mcb outlet. Might narrow it down.""

I wonder if the Solar PV could be the reason I'm reading dc volts?.  I'm back at the house tomorrow and will report back with my learnings.

 

[not_shocked_yet]

Hi Canoeboy,

With the feed back that I have had here and elsewhere I will finish the job I was asked to do which is to identify and rectify the fault causing the RCD to trip in the converted Stable block.  From eliminating the circuits one by one at the stable DB I know which lighting circuit is causing the problem.  As the building seems to have been uninhabited for quite a while I'm assuming it is something simple so will (after safe isolation at the CB) perform a visual inspection followed by continuity and insulation resistance, even if the fault appears obvious - good practice as well.

My client knows that I am recently qualified (if short course counts!) and that my experience is limited.  I will discuss with her that I continue to look at the other issue that I think I have found at no cost to her (I will re-do the tests to be sure) and if I am in any doubt will agree that she must contract another electrician.  I will work FOC with them to gain the experience.

Will report back EOP tomorrow.

PS forgot to ask you what is your tipple?

 

[not_shocked_yet]

Lol.  Are you serious?  I thought it would be a bit of a hike for you?  Anyway, let me double check original readings were taken correctly first!

 

[not_shocked_yet]

Oh no, you mean I have to go to the pub after work tomorrow?!

 

[Andy™]

best ask the local pub to order a few extra pallets of wine, should last the evening if he stretches them out

 

[steptoe]

FK that,

I was looking forward to the dancing girls,,,   :|

 

[not_shocked_yet]

Hello All,

I didn't have time today to check the readings taken last week that have been discussed here as the client needed the RDC tripping issue sorted - which is is!  Loose wiring in the switch plate.

I ran an Insulation Resistance test with 500V at the DB in the stable block.  The system is TT and the stable has it's own earth electrode (according to the client, I haven't looked for it yet but will find tomorrow in the bushes somewhere...)

The IR test recorded the following:

LN  115 mOhm

LE  119 mOhm

NE  0.26 mOhm

There are 7 circuits on the DB (2 x ring final, 4 x lighting, 1 x another I forget what it is)

I will test each individual N to the earth block to see if it is just one circuit which is causing this reading.

Any kind thoughts would be welcome.

Many thanks.

 

[ProDave]

You like to drag it out. Perhaps you like visiting this one customer?

I would have had those neutrals out and tested individually straight away as IMHO you have NOT "found the fault"

 

[Andy™]

Hello All,

I didn't have time today to check the readings taken last week that have been discussed here as the client needed the RDC tripping issue sorted - which is is!  Loose wiring in the switch plate.

I ran an Insulation Resistance test with 500V at the DB in the stable block.  The system is TT and the stable has it's own earth electrode (according to the client, I haven't looked for it yet but will find tomorrow in the bushes somewhere...)

The IR test recorded the following:

LN  115 mOhm

LE  119 mOhm

NE  0.26 mOhm

There are 7 circuits on the DB (2 x ring final, 4 x lighting, 1 x another I forget what it is)

I will test each individual N to the earth block to see if it is just one circuit which is causing this reading.

Any kind thoughts would be welcome.

Many thanks.

if your getting mohm, then something is seriously wrong

 

[Sharpend]

Oh no! not brides revisited!

 

[not_shocked_yet]

Hi Andy,

What do you think I should be reading?

 

[NozSpark]

m is milli

M is mega

It's an important difference

 

[not_shocked_yet]

Understood. M m.  Thanks.

 

[NozSpark]

So instead of a number being

1,000,000

It ends up being

0.001

 

[not_shocked_yet]

Hi Noz, yes, I meant to say that I should have been more precise with the M instead of m in my post.

 

[apprentice87]

Well, as you tested them as a group of 7, you have not learnt much, apart from that the average reading for each L/E and L/N is about 800 Mohms which is good

and the average for each N/E is about 1.82Mohms. Problem being that anything over 1Mohm whilst not good, complies with regs....

You are going to have to pull all the neutrals out and do each one on their own.

john..