flat down neutral to earth reading

[aidley]

Yes was just wondering if a spurred off extractor could effect my readings before I have to put new legs in

 

[Octopus]

30 megohms and similar l to e

So fixed fan, no isolator and relatively decent results??? This doesn't add up

 

[aidley]

Yes except neutral to earth which is zero

 

[Octopus]

Yes except neutral to earth which is zero

I think you need to disconnect the fan and redo the test.

 

[aidley]

So that could bring the n-e down? Hopefully it is that dont really fancy putting a fresh leg in

 

[Octopus]

What is the scope of the work you are being paid to do?

 

[aidley]

Whatever it takes its a mutual exchange on.a social housing house

 

[Octopus]

Whatever it takes its a mutual exchange on.a social housing house

You've lost me

 

[aidley]

Do a periodic and make sure it gets a satisfactory

 

[SPARTYKUS]

So that could bring the n-e down? Hopefully it is that dont really fancy putting a fresh leg in

Deffo disconnect it, but if it's just a 4" double insulated job then there isn't an earth requirement in the fan (obviously). However it will need to have been "dealt" with appropriately (the end of the cpc).

not left flapping and maybe .... Touching something

 

[tony mc]

I have isolated the leg thats down split the ring and put it on 2 20amp breakers so I can leave it safe till Monday!The leg thats down seems to run close to tge extractor looked inside and there is 1 x1.5 but no sign of a fcu so assumed it was part of the lighting circuit! If it has been spurred off the ring could this give me the strange readings

You need to find out if the fan is fed from the RFC or the lights its no good assuming that it is.

I know you say you are getting 0 Meg on the N/E leg of the ring but change your meter setting and test it on low ohms /K ohms to find out what reading you are getting. If it is a very low reading doing the maths will give you a bit of a clue as to where to look !!!

 

[aidley]

Yeah I know will check Monday is it in theory possible that this could be my issue though

 

[Richard Burns]

with a 0.0 MΩ reading on insulation resistance this tends to indicate that there is either a load in place or there is contact between conductors.
A load is unlikely on NE IR, unless there is a local surge protector in circuit, but then the LE would read the same as the surge protector operates.
However testing on low ohms range will give you a better idea; a near zero result there means touching conductors, a reading in ~hundreds of ohms is a load or high resistance joint.
Because the RCD does not trip the resistance would be expected to be a significant result at least above the tens of ohms range.
For a socket circuit not tripping the RCD I would be suspecting that there is still an electronic item (probably not the fan) plugged in.

 

[Had8Lives]

Depending on your supply voltage, the resistance between a conductor and earth can go lower than 0.00 meg ohms before a 30ma fault current will flow and trip the RCD. At 230 volts it's 7.67 kohms

 

[davesparks]

Well you need one as you have to prove the RCD is operating at the correct fault current.

That's what the 1/2x and 1 x tests prove so a ramp test isn't essential.

And an RCD doesn't operate on fault current, it operates on a current imbalance between the L and N in a DP RCD.