Curiously wired light fitting

[Jupiter01]

I was replacing a light over the weekend and had two observations to share with you.
Here's what I found under the ceiling rose of the existing fitting:

This has 3 cables:
1. Live In
2. Live Out
3. Switch

It's also using these peculiar (and presumably very dangerous?) terminal blocks.

The cable with the red sleeving is the switch live from the switch.

The existing light has worked for many years and I only wanted to change for aesthetic reasons.
I replaced the brass connectors with Ideal connectors (contained in the fitting of the new light) and also swapped the Live (currently connected to the Live of the light fitting) and the Switch Live (currently in the Live terminal). The current wiring looks wrong in this regard but was working fine...

The light still works correctly but interested in your comments on the above please. Thanks in advance.

 

[RandomGrinch]

It looks as if someone took the blocks straight out of the old ceiling rose, when they realised the new light wouldn't fit over the top!

 

[jj4091]

I would think someone has been very lucky, I doubt the circuit is rcd protected. It also looks like one of the black cores has melted insulation ( but difficult to tell ) where it leaves the sheath which should not have been reconnected if that is the case.

 

[EFLImpudence]

The cable with the red sleeving is the switch live from the switch.

No. It is(was) the permanent live TO the switch. It is connected to what you have correctly called the live in and live out, isn't it?

The red is the switched live. It is connected to the light. How would it work as you describe it?

It is usually done the other way round but should be obvious to someone who has been here doing similar things for seven years.

also swapped the Live (currently connected to the Live of the light fitting) and the Switch Live (currently in the Live terminal).

No, you didn't. You swapped a red wire and a black wire.

Wires do not know what colour they are.

 

[Jupiter01]

No. It is(was) the permanent live TO the switch. It is connected to what you have correctly called the live in and live out, isn't it?

The red is the switched live. It is connected to the light. How would it work as you describe it?

It is usually done the other way round but should be obvious to someone who has been here doing similar things for seven years.



No, you didn't. You swapped a red wire and a black wire.

Wires do not know what colour they are.

Understood.
In the end I swapped the two aforementioned wires without modifying anything at the switch. I was expecting to need to modify the switch wiring but it wasn't required. Couldn't get my head around that.

 

[Jupiter01]

I would think someone has been very lucky, I doubt the circuit is rcd protected. It also looks like one of the black cores has melted insulation ( but difficult to tell ) where it leaves the sheath which should not have been reconnected if that is the case.

I inspected the cables when reconnecting and there was no visible damage. There is RCD protection on this circuit.

 

[EFLImpudence]

In the end I swapped the two aforementioned wires without modifying anything at the switch. I was expecting to need to modify the switch wiring but it wasn't required.

No.

What does a switch do?

Does it matter which wire is held in which hand?

Couldn't get my head around that.

We realise that.

 

[Taylortwocities]

As mentioned above, you were very lucky not to get the full monty up your arm.
Lesson to turn off power in unknown situations.
As Forrest Gump said
You never know what you’re going to get.