Adding an exterior light

[oldbutnotdead]

Interesting- just looked at the cu here (4 year old CED), i'd struggle to get any sort of padlock through the gap in the isolator, it looks as tho any padlock thin enough to fit would not by itself prevent the isolator being switched back on.
Same problem with the isolator between meter and Henley blocks, though at least i could lockwire that off fairly easily.
Not a major issue here (living on your own has advantages) but hmmmm.

 

[oldbutnotdead]

Interesting- just looked at the cu here (4 year old CED), i'd struggle to get any sort of padlock through the gap in the isolator, it looks as tho any padlock thin enough to fit would not by itself prevent the isolator being switched back on.
Same problem with the isolator between meter and Henley blocks, though at least i could lockwire that off fairly easily.
Not a major issue here (living on your own has advantages) but hmmmm.

 

[bernardgreen]

when there is only one cable in the ceiling rose?

When there is only one twin and Earth cable to the ceiling rose the the wires will be Neutral and Switched Live. ( at least they SHOULD be Neutral and Switched Live ) If the switch is OFF then the Switch Live will not be Live at the ceiling rose.

Are you raising the possibility of this cable inadvertently connecting to the live at the switch?

It has been known for someone to switch the switch ON while a person is working on the ceiling rose or lamp.

"" I thought having some more light would help you to to see what you were doing ""

 

[DetlefSchmitz]

When there is only one twin and Earth cable to the ceiling rose the the wires will be Neutral and Switched Live.

should be Neutral and Switched Live
could be Live and Switched Neutral
No-one should assume anything.

 

[Jupiter01]

https://www.coolconcerns.co.uk/imagelib/CS14_Safe_isolation.pdf

Thanks @Taylortwocities. I found this easier to follow in comparison to the other link.
Should the self-test on my 2 probe tester form part of any of this too?
Also, can I use the circuit I am working on as the basis for verification by switching the breaker to on (verifying power with tester) and then switching the breaker to off to verify there is no power? Or should this be a completely separate circuit?

 

[oldbutnotdead]

What's an example of this when there is only one cable in the ceiling rose? Are you raising the possibility of this cable inadvertently connecting to the live at the switch?

Switch could be switching neutral rather than live
Lamp could be part of a 2 way setup across 2 circuits
There may be others but i've encountered those 2.
It may seem overkill to isolate the whole board but it is certainly 'reasonably practicable' (which is the key phrase in the legislation underpinning risk assessments).

 

[oldbutnotdead]

Thanks @Taylortwocities. I found this easier to follow in comparison to the other link.
Should the self-test on my 2 probe tester form part of any of this too?
Also, can I use the circuit I am working on as the basis for verification by switching the breaker to on (verifying power with tester) and then switching the breaker to off to verify there is no power? Or should this be a completely separate circuit?

I wouldn't trust the self-test. And no you can't- note the requirement to verify the tester on a known live circuit AFTER you've proved dead on your work circuit

 

[bernardgreen]

should be Neutral and Switched Live

I have edited my post accordingly. And will add this not un-known hazard in two way switching where both sides of the lamp are Live

 

[Jupiter01]

UPDATE: I used the plug method in the end.
Thanks for your help