I'm meaning from a Part P / BC point-of-view?

 

Yeah, I realise that this is industrial spec cable rather than domestic, but this is for 24V (i.e. ELV) ffs. Max current will be 3 x 14W 5m LED strips i.e. 2A. The braid will be used for EM shielding, given that dimmer control is fairly noisy.

 

You could have the same is it / isn't it discussion for 24 or 48V PoE over CAT5/6/6a, of course, and pretty much nobody would think that falls under Part P. 

Edited December 9, 2025Dec 9 by Alan Ambrose

Part P does not in most cases stop you running 240V lighting cables, so why do you think it would stop you running low voltage ones?

 

Don't skimp on cable size.  for a given power of lighting lower voltage = higher current.  Many people think they can use bell wire for low voltage wiring.

If you’re worried about noise/interference then surely CY is the choice over SY

3 hours ago, Alan Ambrose said:

but this is for 24V (i.e. ELV)

That's SELV, Safety Extra Low Voltage, old boy  

 

3 hours ago, Alan Ambrose said:

ffs

What someone says when a random Welshman on the 'interweb points out that they've spelt SELV incorrectly 🤦‍♂️😆

1 hour ago, Mattg4321 said:

If you’re worried about noise/interference then surely CY is the choice over SY

I was happy to install YY, until the merchant said they just don't sell any of it! 3-core flex it is.

 

I just observe segregation where things like long LED strips are in the mix, so the DC runs are not bunched with equally long runs of AC stuff; unless it's a small bit of LED which doesn't really seem to ever care how you run the cable.......no complaints yet, so I'll belay starting to panic before bedtime.

 

2 hours ago, ProDave said:

Don't skimp on cable size.  for a given power of lighting lower voltage = higher current. 

This.

 

Under-volt = over-current, and then the LED's are on a shorter lifespan. RIP.

Well the regulations are quite clear. An electrical installation in a dwelling should comply with BS 7671 : 2008 (plus amendments). Said installation becomes notifiable to BC as follows:

 

12.—(6A) A person intending to carry out building work in relation to which Part P of Schedule 1 imposes a requirement is required to give a building notice or deposit full plans where the work consists of—
(a) the installation of a new circuit;
(b) the replacement of a consumer unit; or
(c) any addition or alteration to existing circuits in a special location.

—(9) In this regulation “special location” means—
(a) within a room containing a bath or shower, the space surrounding a bath tap
or shower head, where the space extends—
(i) vertically from the finished floor level to—
(aa) a height of 2.25 metres; or
(bb) the position of the shower head where it is attached to a wall or
ceiling at a point higher than 2.25 metres from that level; and
(ii) horizontally—
(aa) where there is a bath tub or shower tray, from the edge of the bath
tub or shower tray to a distance of 0.6 metres; or
(bb) where there is no bath tub or shower tray, from the centre point
of the shower head where it is attached to the wall or ceiling to a
distance of 1.2 metres; or
(b) a room containing a swimming pool or sauna heater.

 

So presumably if this is a new circuit then it's notifiable as even extra low voltage installations are covered (<50V ac or 120V dc).

40 minutes ago, kandgmitchell said:

 

So presumably if this is a new circuit then it's notifiable as even extra low voltage installations are covered (<50V ac or 120V dc).

But I read the question that @Alan Ambrose wants to run the dc cables for lighting.  Presumably therefore the ac wiring to the switch and to the transformer already exists.  So this is not a new circuit.  So he can do most of the dc wiring he wants without notification, as long as it is not not in a special location.  Which is why in my original reply I said most is not notifiable.

And I would agree - if there is no new circuit then there is no need for notification just compliance with the BS. I find that since you rarely get the entire circumstances explained in a post, it's more appropriate just to clarify the legislation and then let the poster decide if it applies to them or not.