Electrical mystery

[jeeves]

I'm trying to get to the bottom of a mystery.

It started when I replaced an old damaged socket in a conservatory. This socket was fed from a single T+E from the house. It also fed another redundant socket so this was removed at this time. So we are left with the existing cable from the house (red/black/bare) connected to a new socket correctly (triple checked, red>live, black>neutral etc).

This is where the mystery begins. The socket no longer works correctly, and neither does the nearest socket inside the house, which is the one that presumably feeds the conservatory socket.

A TV & video plugged into this socket now cycle on and off, and some wall lights come on at the same frequency even though they are switched off.

Any ideas that might explain why this has started with what amounts to a simple socket swap?

The house could do with a re-wire, but it's my nans house and there's no way should would be able to have it done at this time.

Thanks in advance.

 

[JohnD]

the on and off cycling, likely it is a loose connection, that overheats, then when warm goes open circuit, then cools down, and remakes.

Eventually it will burn away. It might not take your house with it. best to follow the cable back to its source, remaking all connections and testing as you go. Presumably it works OK at the source, so you could start there, or you could start with where you most recently distrurbed it.

Until you have found and corrected the fault, disconnect it at the fusebox.

Beware of "presumably"

Post some photos of all the wires and connections. We like pictures.

 

[jeeves]

The only thing I have disturbed is the cable at the socket swap, that's what doesn't make sense. I'll try to get a photo when I'm next there.

I have a socket tester (martindale eze check) and that shows a wiring fault, though it varies, when the TV is not plugged in it flashes green (all ok) when the TV is switched on it shows a fault. The same thing happens at the new socket, when nothing is plugged in it shows all green, when something is connected and switched on it shows a fault.

I'm not so sure on the loose connection theory as it doesn't explain why the wall lights are coming on while switched off. I haven't started digging around with a multimeter yet, that'll be my next step.

 

[JohnD]

when something is connected and switched on it shows a fault.

You forgot to say what kind of fault it indicates

loose connections often get worse under load.

 

[pjcomp]

Try another new socket - it's not unknown for sockets to be faulty.

pj

 

[Lectrician]

Do the wall lights come on dimmer than usual?

It sounds to me as if there is something dodgy going on with shared neutrals from the wall lights and possibly the socket you removed.

 

[jeeves]

Yes they are dimmer, sort of a glow - horror film style!

John the fault indicated actually changes.

I will try a different socket, when I go next.

 

[THRIPSTER]

Sounds like a connection has been disturbed. As the conservatory is fed by a cable feom the house and the socket in the house is mis- behaving, then why not have a look at the connections behind the house socket - that's a good place to start.

Regards

 

[Scoby_Beasley]

I'm also wondering, for clarity, where was the redundant and removed socket fed from? This replaced socket or the single 'in house' socket? Was it before or after the replaced socket before removal? And how many grey sheathed cables are there now at the single 'in house' socket?

 

[jeeves]

Where the cable emerges from the house it is held in place by clips and has been painted, so I can see it hasn't been disturbed, this cable goes to the broken socket (which has now been replaced). Then another cable went to a separate socket (the redundant one) in the conservatory, this cable and socket have been removed by me.

 

[bernardgreen]

My best guess is the sockets are fed from the red and black in the switch that controls the wall lights,

The red is ( probably ) Live but the black is NOT the neutral, it is a switched live to the wall lamps.

The wall lamps supply a high impedance "neutral" to the sockets which the tester sees as a neutral, But when the TV takes current on the neutral this current flows through the wall lamps and hence they glow. The tester now sees a voltage on the neutral and reports it as a faulty neutral.

I doubt those sockets ever worked.

 

[jeeves]

Thanks for your reply, it is very strange. All of the sockets mentioned have definitely worked up until I replaced the socket. The TV one has always supplied the TV and the conservatory one has been running the fridge and freezer. The wall lights also always worked!!

I was wondering whether the conductors were mixed up somehow in the old socket, but where I have put the right colours in the right terminals, maybe the colours were not right in the first place.

 

[bernardgreen]

It might have been that the sockets had been incorrectly wired with earth and neutral exchanged.

The earth wire would have been acting as a psuedo neutral and this would allow the TV fridge and freezer to function.

For that to happen there could not have been an RCD protecting the circuit.

 

[securespark]

Having just raced through the thread with one eye on the monitor and the other on the cat, could it be that there is a massive coincidence and there is a loose connection in the house somewhere?

Check the connections to the TV socket and to the wall lights (presume they are on the socket circuit via a fused connection unit?)

 

[IJWS15]

Thanks for your reply, it is very strange. All of the sockets mentioned have definitely worked up until I replaced the socket. The TV one has always supplied the TV and the conservatory one has been running the fridge and freezer. The wall lights also always worked!!

I was wondering whether the conductors were mixed up somehow in the old socket, but where I have put the right colours in the right terminals, maybe the colours were not right in the first place.

It may be that the socket you have changed was wired incorrectly (by colour) but correctly (terminal to temrinal) and by wiring it correclty by colour it is now incorrectly wired. i.e. was the red live or was the black. I have seen this in a house we once owned, it also had fuses in the neutrals.

How old is the house and how old is the wiring?