Question Regarding Adding Wiring To Lighting Circuit / Going Down A Cable Size

[ZEDEZ]

I've got a lighting circuit wired in 1.5mm T&E on a 6 amp MCB. There are some lights that I'd like to add on to this circuit, controlled by an existing switch. Due to the position of these lights, the most aesthetically pleasing way to install these lights would be to run cable to the new lights from the furthest existing light, using 0.75mm flex, surface clipped direct.

If I remember correctly, 0.75mm flex is rated for 6 amps.

Provided the additional wiring doesn't push the Zs too high, is there any reason why this shouldn't be done?

 

[telectrix]

why not use 1.5mm flex. it's only a bit bigger, diameter wise.?

 

[ZEDEZ]

why not use 1.5mm flex. it's only a bit bigger, diameter wise.?

I could, but it wouldn't look quite as nice. 0.75mm is just the ticket in this case.

Still, even if I was to use 1.5mm flex, I'd still like to know whether using the 0.75mm would be acceptable.

I can't see why it wouldn't be, but I have a niggling feeling there's something I'm not taking into consideration.

 

[ruston]

You may be thinking of reg 524.1 to be read with table 52.3

 

[Leesparkykent]

The minimum CSA for a lighting circuit is 1.0mm.

 

[Andy78]

Or 0.75mm for flex.

 

[ruston]

And that's the reg number for it lol.
That's to Lee's post , sorry.

 

[Leesparkykent]

Or 0.75mm for flex.

What do you mean Andy?

 

[Andy78]

What do you mean Andy?

Table 52.3 states a minimum size for flexible cables as 0.75mm for general application as it states a minimum for other cables at 1.0mm for lighting and 1.5mm for power.

 

[Leesparkykent]

Table 52.3 states a minimum size for flexible cables as 0.75mm for general application as it states a minimum for other cables at 1.0mm for lighting and 1.5mm for power.

ah got you...I read it as any other application i.e other than lighting, power, etc lol.

 

[Andy78]

ah got you...I read it as any other application i.e other than lighting, power, etc lol.

Ah yeah I see what you mean. I am sure it refers to any other application than a specific appliance.

That said I would not use it myself in the situation in question here, only if fused down. I know it may be allowed by the minimum sizes and CCC charts but it wouldn't feel right, and I'm funny like that.

 

[Adam W]

Ah yeah I see what you mean. I am sure it refers to any other application than a specific appliance.

That said I would not use it myself in the situation in question here, only if fused down. I know it may be allowed by the minimum sizes and CCC charts but it wouldn't feel right, and I'm funny like that.

IIRC the maximum length after a reduction in CSA is 2m.

 

[Andy78]

IIRC the maximum length after a reduction in CSA is 2m.

433.3.1
Where a reduction in CCC occurs but the most onerous CCC in any part of that circuit is protected by the OCPD then omission for overload protection at the point of reduction is allowed and not subject to any maximum length.

 

[ZEDEZ]

Or 0.75mm for flex.

Interesting! Can you see any issues with what I was suggesting Andy?

 

[ZEDEZ]

433.3.1
Where a reduction in CCC occurs but the most onerous CCC in any part of that circuit is protected by the OCPD then omission for overload protection at the point of reduction is allowed and not subject to any maximum length.

Boom, that's great Andy, thanks!