I'm totally baffled !!??

[Torturedsole]

Hi All

New here !

So this has me stumped .

I'm currently renting my house privately and i asked permission to have smart meters installed as i currently have really old analogue ones . When the chap , who was from a subby of Scottish power , Turned up he plugged his socket tester ( cant remember the brand ) and he got the weird reading as i have gotten in the attached pictures ( the fluke one is my own , i have also tried 2 other ones ).
As you can see the red LED lights up even when the switch is off on the socket , but it isn't always present , some times its dimmer , sometimes its not there at all. For instance when i was taking these photos , at first it didn't light up , then after like 30 seconds or so it came on .
The installation has passed its inspection , i have the cert , and i asked the landlord to send someone to take a look to be sure and they said they hadn't see it before . Ive searched the net and i cant find any reason for this ??

Trouble is the subbie wont come out to fit the smart meters as they seem to think its massively dangerous ??

Any ideas ???

TIA !

 

[Dave OCD]

That's to be expected though isn't it?

I must be having a thick moment ?! Thought Zs was Ze + R1&R2 ?

 

[goasis]

I must be having a thick moment ?! Thought Zs was Ze + R1&R2 ?

Interesting, by calculation yes, but would you take a Zs measurement without bonding connected?

 

[Julie.]

The tester apparently didn't even know what voltage he/she was doing the IR testing at, or any mention of how they've managed to get RCD test results when there's no RCD mentioned, and presumably don't know where to find max zs values in bs7671 as they are N/A as well.

Zs isn't really applicable with a TT system as the RCD is providing fault protection, not the mcbs - they would never trip with 315 ohm earth rod.

 

[goasis]

Zs isn't really applicable with a TT system as the RCD is providing fault protection, not the mcbs - they would never trip with 315 ohm earth rod.

Yeah I know... maybe I was over reacting. No excuse for the NA in the IR test voltage tho eh?!!

 

[Julie.]

Yeah I know... maybe I was over reacting. No excuse for the NA in the IR test voltage tho eh?!!

Nope, pure muppetry that one!

 

[Torturedsole]

Yea i can take a photo of the cb.

But we have seemed to of gone wayyyyy off topic here

 

[Julie.]

OK, let's try to explain.

A socket tester basically measures three voltages simultaneously.

The first (LH) green LED indicates that there is some voltage between line and neutral - which there should be in correct operation.

The second (Centre) green LED indicates that there is some voltage between line and earth - which there should be in correct operation.

The third (RH) RED LED indicates that there is some voltage between neutral and earth - which normally there should NOT be in correct operation (at least not too much voltage).

How much voltage? - well that depends on the tester, some containing electronics will indicate at lower voltages than less fancy ones, but typically it may be 50v

So the tester is basically saying there is at least 50v (ish) between L - N -- OK, L - E -- OK, and N - E -- NOT OK.

why are you getting a reasonable level of voltage between N & E - Well that's not too unrealistic with a TT system, the neutral and earth can differ by some amount, these quick testers are not great on TT systems, some are OK as they may trigger at 50v, which would indicate a genuine issue, others may operate at a much lower voltage.

You need firstly to measure the voltage L - E using a high impedance meter (like a multimeter), then via a lower impedance meter such as a MFT (multi function tester), you would need to bring in a proper electrician for this.

Does this actually represent a danger - well it depends on the results - if the voltage measures the same, then you have a genuine voltage, and depending upon the value it is OK, or not.

If the voltage changes between the two measurements, then you have a poor/missing connection, likely in the CPC (earth) which is an issue.

Edit:

Should really have added, that some of the more fancy socket testers actually try to measure the Zs and if greater than a certain value ( typically 1.5 or 2.5 ohm) then the electronics flags it as a fault, and since your Zs are around 315 ohm (TT) then a fancy one would do this.

 

[Julie.]

Also, and not relating to the "issue" , that tester you are using has been recalled for safety issues.

If you contact fluke they will replace it.

Fluke SM100, SM200 and SM300 Electrical Socket Testers Voluntary Recall | Fluke

Fluke Corporation has identified a safety issue concerning the Fluke SM100, SM200 and SM300 Electrical Socket Testers. As a precautionary measure, Fluke has decided to voluntarily recall all of these products and provide affected customers with free replacement products.

www.fluke.com

 

[nicebutdim]

Also, and not relating to the "issue" , that tester you are using has been recalled for safety issues.

If you contact fluke they will replace it.

Fluke SM100, SM200 and SM300 Electrical Socket Testers Voluntary Recall | Fluke

Fluke Corporation has identified a safety issue concerning the Fluke SM100, SM200 and SM300 Electrical Socket Testers. As a precautionary measure, Fluke has decided to voluntarily recall all of these products and provide affected customers with free replacement products.

www.fluke.com

They won't directly replace it, but will send a T90 voltage tester.

 

[Julie.]

They won't directly replace it, but will send a T90 voltage tester.

Yeah, there are a couple of options, neither are that good tbh

The issue is really esoteric, basically if the only connection is one 230v live (neutral or line), then you could get circ 10mA if you touched the earth (when the cpc is missing), so I would be happy to use them in any case.

In saying that, I don't have a socket tester, I fid my mft is perfectly capable of testing socket outlets.

 

[nicebutdim]

Yeah, there are a couple of options, neither are that good tbh

The issue is really esoteric, basically if the only connection is one 230v live (neutral or line), then you could get circ 10mA if you touched the earth (when the cpc is missing), so I would be happy to use them in any case.

In saying that, I don't have a socket tester, I fid my mft is perfectly capable of testing socket outlets.

From the wording in Fluke's recall, I suspect someone got a tingle and fell off their ladder.