Spur plug socket fault.

[UrbanGreen]

Recently discovered a socket in my son’s loft. No obvious power to it. Tried a Martindale socket tester, nothing. Opened the socket. It’s a spur. Tested with non contact voltage tester pen and power was shown to be strangely on live, neutral and earth. Then tried a neon mains tester and nothing was detected at all. Tried two different neon testers both were working prior to this. Any suggestions as to why such strange results were discovered?

I was just doing a quick test on a short visit. Cable runs beneath loft boarding. Socket not actually needed but might have been handy.

 

[ninjacat]

Probably non contact tester was showing a capacitance voltage? A proper 2 pole tester, or a known working lamp plugged in to test for 230v would be better.

You sure it is a spur, could be the end of a radial?

Do you know where its mcb is in the consumer unit?

 

[JohnW2]

Probably non contact tester was showing a capacitance voltage?

Agreed.

A proper 2 pole tester, or a known working lamp plugged in to test for 230v would be better.

He said that he's already tested with a Martindale socket tester.

If he used "a proper 2-pole testter", what two places would you suggest he tested between, given that his non-contact tester has shown potential'on L:, N and E? If it really were true (hardly credible!) that, N, L and E at the socket were all at, say, 230V relative to true earth, then testing between any two of them with a 2-pole tester would be expected to show a zero PD!

Kind Regards, John

 

[ninjacat]

It was more a response to the fact that he didn't seem confident in the results. As in the non contact tester showed potential on live neutral and earth, which is odd, even though the martindale showed no voltage.

 

[JohnW2]

It was more a response to the fact that he didn't seem confident in the results. As in the non contact tester showed potential on live neutral and earth, which is odd, even though the martindale showed no voltage.

I understand that, but was still wondering how you were suggesting he could use 2-pole tester, to clarify his observation (with a non-contact tester) that all three conductors appeared to be 'live'.

Kind Regards, John

 

[UrbanGreen]

Probably non contact tester was showing a capacitance voltage? A proper 2 pole tester, or a known working lamp plugged in to test for 230v would be better.

You sure it is a spur, could be the end of a radial?

Do you know where its mcb is in the consumer unit?

It could be end of a radial if the feed is what I now suspect it might be, a former electrical shower feed.

Not checked for the mcb. I was only on a quick visit and took some some basic bits believing it might be a simple quick fix. I’m 250 miles away from my son’s home. Only went down for my granddaughter’s birthday.

I was just taken aback by all three wires showing power on the non contact pen and then nothing on the neons.

 

[ninjacat]

I understand that, but was still wondering how you were suggesting he could use 2-pole tester, to clarify his observation (with a non-contact tester) that all three conductors appeared to be 'live'.

Kind Regards, John

It would prove no 230v was present. You could take a wander lead to it from the MET?

Either way if it helps satisfy your your pedantic way, it was just a thought and I am sure you are absolutely correct in your observation.

Cheers

 

[JohnW2]

It would prove no 230v was present.

Yes but, since it's something the OP would need to know if he were to do it (with a 2-pole tester) I was attemping to get clarification as fregards 230V 'between what and what" (so that the OP would know what to connect his '2 poles' to -) ). However, you have now offerd one possible answer, when you write ...

You could take a wander lead to it from the MET?

Either way if it helps satisfy your your pedantic way, it was just a thought and I am sure you are absolutely correct in your observation.

I wasn't really trying or intending to be pedantic. There is a tendency for people to produce a 'knee jerk' response to any mention of a non-contact testers or neon screwdrivers by saying "use a 2-pole tester" but, even if the OP in question knows what that is, they are often left wondering what they should connect the 'two poles' of such a tester to - hence my attempt to get that clarified (for the benefit of others, obviously not myself).
'
Kind Regards, John

 

[UrbanGreen]

OP used to use a two pole tester regularly in a previous job.

 

[ebee]

I`ve seen some two pole tester giving "Phanton Voltage" indications. something with a small load on it might be appropriate.
Fliament lamps are not as easy to get hold of as they used to be but a cheap multimeter with a suitable W rated resistor accross the leads might help as a DIY test. Or indeed one of those cheap two pole testers but with a suffient W rated load resistor to bleed out and phamton voltages

 

[JohnW2]

OP used to use a two pole tester regularly in a previous job.

Have I missed something - how do we know that?

Kind Regards, John

 

[JohnW2]

I`ve seen some two pole tester giving "Phanton Voltage" indications. something with a small load on it might be appropriate. Fliament lamps are not as easy to get hold of as they used to be but a cheap multimeter with a suitable W rated resistor accross the leads might help as a DIY test. Or indeed one of those cheap two pole testers but with a suffient W rated load resistor to bleed out and phamton voltages

Indeed. I don't think that people necessarily realise that, at least in literal terms, "2-pole tester" does not mean anything other than that it has '2 poles' - without necessarily meaning anything in terms of the 'type of testing' or its input impedance.

As you imply, when such a tester was merely a filament bulb and a couple of leads, everything was straightforward. However, in the present day of 'electronic gizmos' it's not impossible that a '2-pole tester' will have a very high input impedance and hence be potentially susceptible to "phantom voltages".

Kind Regards, John

 

[DetlefSchmitz]

Have I missed something - how do we know that?

Kind Regards, John

umm...

 

[UrbanGreen]

Have I missed something - how do we know that?

Kind Regards, John

Because I am the one who said it. I used to use 2 pole testers fault finding on electrical appliances in my former trade.

 

[JohnW2]

Because I am the one who said it. I used to use 2 pole testers fault finding on electrical appliances in my former trade.

Fair enough, but I'm still wondering what I've missed (and how) - where/when did you 'say it'?

Kind Regards, John