Buying wire

[BillyD]

For general purpose project/hobby work with breadboard or perfboard, 0.6mm single strand is good.
Or if you prefer more flexible wire, stranded cable 7 x 0.1mm is roughly equivalent - good for soldering but can't be poked into the holes on a breadboard.
The search term you need is 'Equipment wire', if you search for this on ebay you'll get lots of options. Eg: a 30m pack of 6 different colours, each 5m will go a long way for the hobbyist.

[TimFox]

Having been misled in the UK on an earlier trip, I now am careful to use “mm²” for metric wires.  I assume that you mean mm², not mm.

[Terry Bites]

Amperage,volteridge and ohmage go together. Keep clear! Current carrying capacity is the polite terminology.
For most signals (<48V) and low power devcies (<1A) 0.5mm² is fine.
Thinner stuff is harder to strip without breaking and ruining your day. Sometimes it'll break inside where you can't see it- thats trip to hell. Silicone is great for test leads and HV and hot envirinments, but usually PVC is your man. Don't buy cheap crap and invest in a wire rack (broom handle). Some of the stuff on ebay isnt even copper or aluminium but copper plated steel. Its magnetic!
Its generally referred to as hookup wire or equipment wire.
eg https://cpc.farnell.com/search?st=stranded%20equipment%20wire%200.5%20mm%C2%B2
or https://uk.rs-online.com/web/c/cables-wires/wire-single-core-cable/hookup-equipment-wire/
Ribbon tends to peel badly, exposing the parts you'd rather not. Use Kynar wire for PCB bodging, but solder with a very light touch.
Look at cross section area vs capacity https://www.engineeringtoolbox.com/wire-gauges-d_419.html

Old wire is bad. Moisture wicks up between the conductor and the outer plastic over the years causing corosion and brittleness.

[tkamiya]

In Japan, we call thin hook up wires by number of strands, such as 10 strand wire or 16 strand wire.

I've never heard of official designations until size equivalent to mains cord such as 0.75mm^2 or 1.25mm^2.

[Zero999]

Having been misled in the UK on an earlier trip, I now am careful to use “mm²” for metric wires.  I assume that you mean mm², not mm.

Be careful, asking for millimetre squared can create confusion. When I asked for 1.5mm squared heat resistant cable, for an immersion heater, in an electrical shop, the person working there, said they didn't have any square cable, only circular.  The problem is, cable, with three conductors running parallel to make it flat, is rectangular, is available in the UK and he probably thought I meant that, when I said squared, which is likely misheard as square. In short, when in the UK, say 1 mil, if you really mean 1mm², whilst not technically correct, it's more widely understood. Of course always write 1mm², which is unambiguous.

[tooki]

Amperage,volteridge and ohmage go together. Keep clear! Current carrying capacity is the polite terminology.
For most signals (<48V) and low power devcies (<1A) 0.5mm² is fine.
Thinner stuff is harder to strip without breaking and ruining your day. Sometimes it'll break inside where you can't see it- thats trip to hell.

If you’re causing that kind of damage to your thin wires, you’re doing something seriously wrong!!

As with anything, you have to match tools and techniques to the workpiece. There’s no wire stripper in the world (except for thermal) that’s suitable for both very thin and thick wires.

IMHO, 0.5mm2 is far too thick for many electronics applications. The number of connectors designed for 0.25mm2/24AWG maximum demonstrates this.

[msknight]

I did manage to find a cross reference between mm2 and awg. So you're saying that the 20awg I've ordered is going to be too thick, and I should have gone for 24.

AWG    mm2
30        0.05
28        0.08
26        0.14
24        0.25
22        0.34
21        0.38
20        0.50
18        0.75
17        1.0
16        1.5
14        2.5
12        4.0
10        6.0
8        10
6        16
4        25
2        35
1        50
1/0        55
2/0        70
3/0        95
4/0        120
300MCM    150
350MCM    185
500MCM    240
600MCM    300
750MCM    400
1000MCM    500

[tooki]

I did manage to find a cross reference between mm2 and awg. So you're saying that the 20awg I've ordered is going to be too thick, and I should have gone for 24.

The best answer to “which wire sizes do I need?” is “yes!”

What I mean is that there’s no one-size-fits-all size.

I like 24AWG/0.25mm2 for tons of stuff (jumper wires, thin test leads, etc). But for other things one needs thinner or thicker. I also have 0.5mm2, 0.75mm2, 1mm2, as well as some 28AWG and 30AWG — at home. I can access even more at work…

For the 1/4” spades on the switches in the pic, the 0.5mm will be great. For the smaller pin header on the joystick (which looks like a 0.1”/2.54mm pitch), 0.5mm2 is gonna be difficult to crimp onto the connector.* 24 or 26AWG will be better.

* there do exist female contacts for 0.5mm2 for that kind of header, but they’re harder to find. Not to mention the god-awful rabbit hole that small-connector crimping is! 

[Zero999]

I did manage to find a cross reference between mm2 and awg. So you're saying that the 20awg I've ordered is going to be too thick, and I should have gone for 24.

Looking at the picture, attached to your previous post. You probably need different sizes. The spade crimps, probably need at least 0.5mm² and the connector on the joystick, about 0.1mm² to 0.25mm². What do the data sheets for the connectors/crimp sockets say?

[msknight]

I'm not using spade connectors. I'm directly soldering to the tags.

The reason for this is that some of those tags will have three cables attached, one from the previous LED, one to the next LED in the parallel chain, and in the case of the ground, a third to attach to the top tag... because the ground for the LED and the ground for the microswitch, will all go to the same common ground on the Pro Micro board which will drive the project... https://github.com/MickGyver/DaemonBite-Arcade-Encoder - yes I know I'll have to de-solder if I have to replace anything, but it's going to be easier than trying to stuff three cables into one spade.

[james_s]

It won't hurt anything to solder them, although it's easy to crimp multiple wires in the same terminal too.

[Zero999]

I recommend crimping, rather than soldering, especially as you want to connect many wires to one terminal. It can be difficult to solder to large spade connectors, especially more than one wire and there's a risk of the heat damaging the component, although I think the latter is unlikely in this case. It's much easier and safer to simply put the wires into the same crimp connector.

[mariush]

If you want AWG24 wire, you could buy solid core ethernet cable, and you have 8 insulated wires inside, in 4 pairs. There's also stranded wire cable if you want more flexibility.

Make sure the cable is not CCA, that's aluminum wire plated with copper and has higher resistance.

[msknight]

I can't use spades because I'm jamming in decent arcade buttons with micro switches, into a case designed for shallow, lower quality buttons. The micro switches are nearly hitting the bottom of the case already. I don't have the headroom... unless I bend the LED spades sideways a bit..... hmmm...

[Jwillis]

I can't use spades because I'm jamming in decent arcade buttons with micro switches, into a case designed for shallow, lower quality buttons. The micro switches are nearly hitting the bottom of the case already. I don't have the headroom... unless I bend the LED spades sideways a bit..... hmmm...

Not sure of what kind of supply you have available to you but you could use 90 degree spade connectors (Flag terminals). Then you can avoid any bending.

[tooki]

I can't use spades because I'm jamming in decent arcade buttons with micro switches, into a case designed for shallow, lower quality buttons. The micro switches are nearly hitting the bottom of the case already. I don't have the headroom... unless I bend the LED spades sideways a bit..... hmmm...

Or use the “flag” style right-angle spade connectors designed precisely for this purpose. (Admittedly, they’re not as ubiquitous as the regular style, but still readily available from electronics distributors as well as AliExpress etc.)

A few styles of these are visible in the attached photo:

[msknight]

Well well... flag spades... I learn something new every day! Many thanks to you both, posting within a couple of minutes of each other.

[mindcrime]

Well well... flag spades... I learn something new every day!

You and me both. I've been dabbling with electronics as a hobby for 35 some odd years now, and I don't think I'd ever seen those "flag" spades until today.

Obligatory XKCD: https://xkcd.com/1053/

[james_s]

They're all over the place, very common in appliances like washing machines, dishwashers, air conditioners, and other equipment. I've seen them quite a few times inside consumer electronics too, such as where the line cord connects to the PCB.

[tooki]

Well well... flag spades... I learn something new every day! Many thanks to you both, posting within a couple of minutes of each other.

You’re very welcome!

Oh yeah, I meant to say above but forgot: FYI, as you might imagine, the flag terminals are not at all compatible with a crimping tool for the regular kind. A decent AliExpress one should do fine for non-critical applications like this.