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You have to read the table left to right.

The first column is "type of wiring system" and the first row is "non-sheathed and sheathed cables." If you're using this type of cable, then I agree minimum size is 1mm for lighting, 1.5mm for power (assuming copper).
The second row is "bare conductors" - not relevant here.
The third row is "non-sheathed and sheathed flexible cables." This is a different row from the first row, and there are different requirements. Under "use of the circuit" (2nd column) you've got "for a specific appliance" (not relevant here), and "for any other application", which is. 0.75mm.

So rather than reading it as, "lighting says 1mm, so 1mm", you start off by asking which type of cable, then what the application is, then the minimum size.
Well having read the table from left to right I still say 1mm2 I/is the min for a lighting circuit.
 
Well having read the table from left to right I still say 1mm2 I/is the min for a lighting circuit.
Ok, let's try this:

Which of these two descriptions most accurately describes the "flexible cable" we're talking about? Is it:

(a) "Non-sheathed and sheathed cable,"

or

(b) "Non-sheathed and sheathed flexible cable."
 
So the flex cable needs to be replaced for 1mm cable?
Don't understand any of the recent posts, trying too!
w/Without the pleasure of seeing the install, and from what you have said so far, my advice would be to get it looked at by a competent Electrician
 
Ok, let's try this:

Which of these two descriptions most accurately describes the "flexible cable" we're talking about? Is it:

(a) "Non-sheathed and sheathed cable,"

or

(b) "Non-sheathed and sheathed flexible cable."
b
 
Ok, let's try this:

Which of these two descriptions most accurately describes the "flexible cable" we're talking about? Is it:

(a) "Non-sheathed and sheathed cable,"

or

(b) "Non-sheathed and sheathed flexible cable."
If 0.75mm was suitable for lighting circuits manufacturers would produce T&E in this size.
 
Great, so we go to that row of the table (near the top of page 145 in the blue book, or page 134 of the old yellow book). Now read across for application, is it:

(a) for a specific appliance? (no)
(b) for any other application? (yes)
(c) extra-low voltage circuits for special applications? (no)

Minimum size for (b) is 0.75mm

If 0.75mm was suitable for lighting circuits manufacturers would produce T&E in this size.

No, because T&E uses solid (or, for larger sizes) stranded copper conductors, rather than flexible conductors. The minimum size for these is 1mm, and for good reason - they'd be too easy to break if smaller than 1mm.

Have you ever wondered why the cpc on 1mm T&E is not smaller than 1mm? It's not because of the adiabatic. It's because it would break too easily.
 
... but in response to the original poster: the installation method is "unconventional" to say the least, you should certainly have got an Electrical Installation Certificate as the work involves the provision of a new circuit, and the work should have been notified to Building Control. Unless the flex has had bootlace ferrules put on the end of it before termination in the consumer unit, it has not been installed correctly.
 
... but in response to the original poster: the installation method is "unconventional" to say the least, you should certainly have got an Electrical Installation Certificate as the work involves the provision of a new circuit, and the work should have been notified to Building Control. Unless the flex has had bootlace ferrules put on the end of it before termination in the consumer unit, it has not been installed correctly.
Away from the discussion about 1mm or 0.75mm, who or what sort of person would wire the garden lights in 1.5mm3 SWA cable, and then lash it on to a length of 0.75mm2 flex, answers on a post card please.
 
(b) for any other application, no it is lighting. The cable is undersized.
Why would you take the rule for the minimum size of a different type of cable?

Ok, suppose for a completely different application, you were using bare conductors (second row), but you were using it for a lighting circuit rather than power. Minimum size for "power" for bare conductors is 10mm (copper), would you go "ah, but elsewhere in the table it says lighting 1mm, so I can use 1mm for lighting circuits if I use bare conductors"? No, of course not.

First sort out what sort of cable you're using: ignoring bare conductor cable, is it flex, or not? If flex, you look at what the use of the circuit is, and size accordingly. If not flex, you do the same. You don't pick and choose "use of circuit" and then apply it to the three different types of cable listed.
 
There could be a small chance that it is white FP200 but I am assuming that the OP has felt it and it is flex then its not good practice even if it is adequately fixed.
 
Yes the use of circuit is lighting no matter how much you juggle it. Bare conductor sizes are irrelevant.
I think we're going to have to agree to disagree then.

My logic, reading table 52.3 (ignoring bare conductors):

Is it flex, or not flex?

If not flex, minimum size = 1mm for lighting, 1.5mm for power.

If flex, minimum size = 0.75mm, unless specified in the product standard for a specific appliance.
 
I thought 0.75 flex was only allowed for pendant wiring etc?
 
I thought 0.75 flex was only allowed for pendant wiring etc?
You got a reg number for that? :)

The only thing I can see specific to pendant wiring is 411.3.1.1, which is about not having a cpc, rather than sizing: "A circuit protective conductor shall be run to and terminated at each point in wiring and at each axcessory except a lampholder having no exposed-conductive parts and suspended from such a point."
 
Never really comment, just enjoying reading. Just wondering with all comments if 1mm is minimum allowed for lighting, how come 0.75mm flex is supplied with most pendants, surely this must class as part of the lighting circuit?
 
I'm going to have to go with Happysteve,on this one,purely on the basis of working backwards from a potential incident or investigation,the regs could not be straightforwardly used,to indicate an incorrect selection of materials,in this specific example.

The lighting issue evaporates,if the same circuit powered a garden sound system,of the same load ;)
 

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