Phase Neutral Reverse Fault on Kitchen socket

[intamixx]

I have a strange problem with some sockets in my kitchen and was wondering whether anyone can shed some light on was is occuring.

I have a "master" twin socket that has a "slave" single socket. Both sockets are in the kitchen and on the inside wall facing the garden. The single socket was put in about 3 years ago when I had the kitchen refurbished, the twin socket has been there for at least 20 years. Both sockets are flush "in" the wall, with the plastic face-plates extruding out.

I have a Martindale socket tester and a electric tester screwdriver.

Ok, I have unscrewed the master socket plate from the wall and it is fine and the socket tester states it is wired correctly for both sockets. If I touch the electric tester screwdriver on its metal back box, it shows no current. There is a slave 3 core wire that is connected to the earth, neutral, live connectors of this twin socket. It is going up out of this metal back box into the wall, I believe trunked over the outside kitchen door, and then going into the "slave" single socket. Of course this is all in the wall so I'm not 100% sure how it gets there. (I vaguely recall seeing the wiring trunked into the wall when the refurb took place).

If I touch the electric tester screwdriver on the single socket metal back box, it shows a current. In fact earth, live and neutral on the socket are showing current. If I use an electric socket tester with the single socket front switch in the off position, the socket tester shows the middle light is on. If I turn the single socket front switch on, 2 lights on the socket tester turn on, which indicates a phase/neutral reverse fault.

If I disconnect the "slave" cable from the master twin socket, all current from the single socket is gone. This is how I have left it, in the disconnected state.

Does anyone have any idea what is causing this? I have attached some pictures of the single socket with the switch on and off, and of the master twin socket. I have already replaced the master twin socket front plate today, but the same result is still occuring.

Many Thanks.

 

[Echo the husky]

Line and neutral reversed at the second socket? What size fuse/MCB is protecting the circuit?

 

[deadshort]

Brown to L , Blue to N on the single socket. The circuit should be on a 20A or 16A breaker if it is wired as shown. (Unless the twin socket is fed via a FCU.)

Regards,

DS

 

[Taylortwocities]

he circuit should be on a 20A or 16A breaker if it is wired as shown. (Unless the twin socket is fed via a FCU.)

Need to see the wiring at the back of the single socket. As above, it would seem that the single socket wiring may be reversed.

In addition, as alluded to by DS. The double socket looks like it is a spur, that would make the single socket a spur from the double (ie a spur from a spur). That is not correct if the circuit is a ring final.
Did the person who installed it look like this?

 

[ban-all-sheds]

If I touch the electric tester screwdriver on its metal back box, it shows no current.

You really, really, really, must, absolutely must, learn what the difference is between voltage and current, and what the limitations are of those "testers".


And stop all this "master - slave" nonsense.

If I touch the electric tester screwdriver on the single socket metal back box, it shows a current.

No it doesn't.

In fact earth, live and neutral on the socket are showing current.

No they aren't.

https://www.google.co.uk/search?q=voltage+current+101&ie=utf-8&oe=utf-8

If I use an electric socket tester with the single socket front switch in the off position, the socket tester shows the middle light is on. If I turn the single socket front switch on, 2 lights on the socket tester turn on, which indicates a phase/neutral reverse fault.

Surely it is utterly trivial to look and see how the socket is wired?

I have already replaced the master twin socket front plate today, but the same result is still occuring.

Well durrr... if the other socket is miswired then of course it will.

 

[ericmark]

From memory the testers compare the line and neutral to earth, is if no earth it will give odd results.
Well done highlighting the problem.
Also well done with solution, disconnecting is the right move.
The tester you have is limited, there is a slightly better one called EZ150 which does tell more, but as already pointed out there are a few problems with helping you.
1) Wiring behind the single socket.
2) The supply to double socket.
Step one is find out size of MCB supplying sockets, if 25A or less then worth going further with picture of single socket wiring, if over 25A then some rethinking needs doing.

The double we hope is either supplied with a 25A or less MCB, and if not then it is the first socket from the ring, or it uses 4mm² cable. But we all know likely it will need a FCU before it can be extended.

But so far you have done everything right, so full marks.

 

[EFLImpudence]

...and you need a new camera.

 

[securespark]

And stop all this "master - slave" nonsense.

Oh, I dunno...I quite enjoy playing "master-slave" with Mrs Secure.

 

[Risteard]

And he/she should have isolated the supply before unscrewing the socket outlet from the backbox too.

 

[sparkwright]

As said, we need to see which wires goes in which marked terminals.

On first impressions it would appear the single socket is connected wrongly.

(Or if everything DOES APPEAR to connected correctly, then they might be a hidden joint somewhere wired wrongly.)

I'm assuming you've checked the wires at the single socket ARE in the correct terminals?

You need to confirm this, as this is the difference between a simple problem and a not-so-simple problem.

The single back box MAY appear to be live PERHAPS because the box isn't earthed - unlike the double box. This MAY be induction.

Until we get more detailed pictures it's hard to tell for sure.

 

[intamixx]

Hello,
Thanks for the replies.
I triple checked that the single socket was wired correctly. Live(brown), neutral(blue), earth (yellow/green). It looked good to me but no I don't have any pictures of it, will try to get some.
I attach pictures of the consumer unit, which is quite old. I took these pictures last month.
Just i'm curious as to why the single socket appears inducted and the spur off a spur issue.
Thanks.

 

[ban-all-sheds]

The single socket was put in about 3 years ago when I had the kitchen refurbished

Clearly not by a competent electrician, as there's no RCD protection on the socket circuit. 3 years ago the Wiring Regulations mandated one.

 

[Taylortwocities]

I triple checked that the single socket was wired correctly. Live(brown), neutral(blue), earth (yellow/green).

Yes, those are the colours, but what terminals are they connected in to? Just want to make sure we aren't missing something obvious.
If that is correct then it's time to check the consistency and continuity of the spur cable. There may be another connection, or another socket somewhere.

 

[deadshort]

Hi, the Martindale tester you have does not appear to have a fault condition which results in only the centre neon lighting being lit ? That tester will not indicate a neutral /earth reversal or a short between the neutral and earth. As has been said you have an issue with the cable linking the two sockets. You need an electrician with test kit as you may have a nail or screw through the cable. Also the spur from a spur is an issue as the your sokets would appearto be on a 30a fuse. It is perhaps a good time to have a general check of your wiring and earthing arrangements.

Leaving the single socket disconnected from the double socket is a wise move until you have it checked.

Regards,

DS