Try here for your wire and anything else. Brilliant service and advice.
https://www.componentshop.co.uk/
👍👍

Hi mouldbuilder, have you tried a company called CPC? They seem to have a sister company called Farnell.Maybe 1 L? Hope this helps you out.Good luck

Another good source of cable i use are network cables. pain to strip but each one has normally 8 cables inside.

I had an email from 'Haverlock' making the point that 'my' formula is no good for motors, etc. I agree. I did state it was for LED supply resistors. I found several references to this formula among which were 'Sparkfun' and the book "Introduction to Analogue Electronics". Any dissenters should take it up with RS - that's where I found it about 40 years ago. Case closed.

Hello, try looking for old 25way data cables at your local car boot sale. The cores are multi-coloured and very thin. Most LEDs only use a breath of current to drive them so you won't start a fire! Here's a tip about dropper resistors for LEDs: put them at the power supply end where you can tie them down securely. Also, the formula for finding the resistance you need is: R equals Volts(supply) minus Volts needed by LED (Vf) divided by the required LED current (If). So, say 12V supply, 2V LED wanting 15mA = 12-2=10/.015 = 666.667, so you'd use the nearest value above, which would be 680ohms. Easy! The size of the resistor in watts/milliwatts is found by I(current) times E(volts), so 10X.015=.15W, or 150mW. Hope I'm not teaching an old sea dog new tricks!
Starting a new Firefloat - oh boy.😲

Thanks for all of your help. I will check out all of the above and report back.
Thanks again.👍😊

Just to provide some more specifics on overall diameter, I have WW wire that is 30ga but the insulation adds variable amounts to that. E.g. one is 0.43mm dia, another is 0.75mm diameter.
The solder-able wire that I use is 0.15mm diameter. That is available here: http://www.roadrunnerelectronics.com/epages/BT3782.sf/en_GB/?ObjectPath=/Shops/BT3782/Categories/Wire

I still occasionally wire prototypes up using the Vector P173 wiring pencil :-)

Redundant computer ribbon cables are also a good source, providing many colours. Even the connectors are useful for non essential stuff like lighting.
😎

The inards of USB cables is very small, and stranded. Often available for few $ at thrift shops.
I find WW wire (30ga) plenty robust for most things, used it a LOT in the 70's for backboards on mainframes. Solders very well. if the runs are long-ish then add a clip every few inches for support.

If you need really really thin then magnet wire would be your next option. There is solder-able stuff available where the insulation dissolves under high temperature. insulation is otherwise quite robust.

Have a look for intruder alarm wire comes in 4 and 6 core and is stranded as opposed to solid wire which a lot of the telephone wire was ( dunno if it still is)

https://www.ebay.co.uk/itm/Alarm-Cable-6-Core-White-Intruder-Burglar-Secuirty-Wire-PVC-Insulated/252492643054?hash=item3ac9bbfaee:m:mv4ZmI2-stkMj17vCG6Go4w:rk:3:pf:0

if you need thinner still ( and unless the wire is supported VERY well I advise against it ) use wire wrapping wire.

https://www.ebay.co.uk/itm/0-25mm-Wire-Wrapping-Wire-30AWG-Cable-305m-New-Red-T4D5/123178150109?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D52543%26meid%3D17f03e5b33dd44069a6017a2c126df6e%26pid%3D100005%26rk%3D3%26rkt%3D8%26sd%3D121195610390%26itm%3D123178150109&_trksid=p2047675.c100005.m1851

hope this helps

Thanks Colin.😊

Hi Peter, I use gpo telephone wire, the black outer cover has either 3 or 4 pairs of colour coded wire, it strips and solders very easily. I usually ask a bt engineer for offcuts when I see them working in my area. The od of the outer cover is about 8mm. The individual wires are about 1.5 od over the cover.
Hope that this will help you.
Cheers Colin.