Old wiring system confusing

[markgwilson]

Hoping someone can help with the following:

We have a tatty 1970s porch light which I replaced last weekend with a new, motion and night operated carriage lamp. Nothing fancy, just from Homebase. The light is switched on/off from inside the hall.

When I remove the old light fitting I find my 1970s house still has 1970s wiring. There are two black wires, one with a red tag and two red wires along with a two short exposed copper wires wound together.

On the old light the wiring went like this:

Black wire with red tag into left hand connector
Both red wires joined together in middle connector
Black wire with no tag in right hand connector
The exposed copper wires were wound together and not attached to anything

So, having seen something similar upstairs when refitting a ceiling rose, I wired the new light fitting up in what I thought was the right way below:

Black with red tag (which I believe is the switched live) to live
Two red wires I isolated into seperate connectors, bound with tape and tucked out of harms way back into the wall
Black with no tag to neutral
Exposed copper wires I left as previous
Nothing into the earth

Now what I get when I switch the light on in the hall (and having covered the light/motion sensor to simulate darkness) is the light flickering randomly on and off like a strobe, sometimes staying on for a few seconds. The same process occurs at night when it is properly dark

Any thoughts?

Mark

 

[Steve]

Is this a PL base CFL fitting? (Energy saving with a square base)

If so, change the lamp.

If no joy, its ronnied. These cheap PL fittings from Homebase and B&Q are el crapo. Take it back and get something decent. If you must shop at Homebase, buy a seperate photocell and a normal fitting that can take BC or ES CFLs.

We have a fitting at work that defeats itself - When it gets dark, it comes on. Then it defeats the photocell and goes off (its a round fitting, throws light all around, its under a white canopy). It repeats this over and over all night.

 

[xr4x4]

I think you will find that bare wires are the earth, check this and fix to earth of your new light fitting.

 

[ColJack]

we need more info on the new fitting.. make, model, wiring diagram if possible, photo of the terminals etc..

it may need a permanent live or something else.. we don't know without the info..

 

[markgwilson]

Steve - thanks. Yes its as you describe. I have just replaced the CFL bulb with an old style filament bulb and the unit now seems to be working....appreciate the help

 

[SimonH2]

When I remove the old light fitting I find my 1970s house still has 1970s wiring. There are two black wires, one with a red tag and two red wires along with a two short exposed copper wires wound together.
...
Black with red tag (which I believe is the switched live) to live
Two red wires I isolated into seperate connectors, bound with tape and tucked out of harms way back into the wall
Black with no tag to neutral
Exposed copper wires I left as previous
Nothing into the earth

If that is what I think it means then ... oh dear.

Do those individual wires arrive in the form of two "twin & earth" cables ? If they've been stripped right back then you might not be able to see.

What I'd expect with this combination of wires is :
The two reds are live supply in and live out to switch - they will need to be connected together AND insulated. I'm surprised it works at all with them separated.
The black is neutral
The black with red sleeve (at least they did that bit right) will be the switched circuit back from the switch.

The uninsulated wires will be earths. They MUST be connected together (and to the fitting earth terminal if it has one). "twisting together" is not an acceptable jointing method and this leaves your light switch and light fitting inadequately earthed.

 

[ban-all-sheds]

Both red wires joined together in middle connector
.
.
Two red wires I isolated into seperate connectors,

And the reason you thought that was the right thing to do was....?

Nothing into the earth

And the reason you decided not to earth the new light was?

Any thoughts?

Yes - get an electrician, you are dangerous and ignorant.

 

[markgwilson]

Both red wires joined together in middle connector
.
.
Two red wires I isolated into seperate connectors,

And the reason you thought that was the right thing to do was....?

I can see how my post would be confusing. Let me try again. The two red wires I isolated jointly into one connector; that connector was seperate and insulated away from the lamp connector. I did this because I had understood they were the in and out live from the main circuit.

Nothing into the earth

And the reason you decided not to earth the new light was?

Because I was unsure exactly whether the two bared crossed wires were in fact an earth and wanted to check first. I had no intention of leaving it this way permanently and in fact the light was taken down and safely capped off in the meantime.

Any thoughts?

Yes - get an electrician, you are dangerous and ignorant.

I am assuming you are attempting to be helpful here rather than just smart-arsed or rude?

 

[SimonH2]

Yes - get an electrician, you are dangerous and ignorant.

I am assuming you are attempting to be helpful here rather than just smart-a***d or rude?

I think he's being both (though helpful only comes if it doesn't get in the way of the latter) - it's the only mode he seems to have. If you stick around you'll get used to it

 

[ban-all-sheds]

I am assuming you are attempting to be helpful here rather than just smart-a***d or rude?

The former and absolutely not the latter.

Remember I wrote that before you'd pointed out that "Two red wires I isolated into seperate connectors" actually meant that you'd connected them together in the same connector, and after you'd reported that the results of your changes were that the light didn't work.

I think "ignorant" is a fair description of someone who'd done what you claimed to have done.

And whether you intended to leave it like it or not, the fact remains that you did connect a Class I item to a supply without earthing it and energised it, and that was dangerous.

So yes - in your own best interests, I advised that you should get an electrician.

 

[TonyS]

BAS No wonder your heading for a ban on another forum! Ignorance of a subject is one thing. Being rude and ignorant is another!

 

[ban-all-sheds]

BAS No wonder your heading for a ban on another forum!

Am I?

Ignorance of a subject is one thing. Being rude and ignorant is another!

Please show me where I was rude.

Do you not think that someone who, if as he had said, had actually taken 2 red conductors which had been connected together and to a light and not only not connected them to the new light but also separated them, is ignorant of how lighting circuits work?

If you do not, please explain how such an alteration would be supported by knowledge of lighting circuits.

And would you also please explain why not earthing a Class I light and then energising it is not dangerous?


I am genuinely of the opinion that someone who goes around disconnecting conductors because he doesn't understand why they are connected, doesn't bother to earth Class I appliances and doesn't recognise cpcs is best off getting an electrician.

You may well disagree, but can you really put forward an intelligently argued case which shows that not only am I wrong to have that opinion but that it is also rude to voice it?