The term ‘ga’ stands for ‘gauge’ and is sometimes called ‘AWG’ which stands for American Wire Gage. Most any wire you buy will use one of these three terms. Note that the larger the number for gauge, the smaller the wire. So a 24 gauge wire is significantly smaller than 18 gauge wire. Wire gauge is defined by the number of operations that historically were used to produce the wire. The smaller the wire, the more operations that were needed to produce it.
Stranded wire just means that inside the insulation there are many strands that make up the wire. If a wire is put in place and not moved, then it is often solid core wire like the wiring in your home or the wiring between the door bell button and the bell, or the wires between your thermostat and your furnace. Any time the wire has the potential to move, stranded wire is a better choice. It can be fatigued much more before it begins to break, so in a CNC machine where the wires are moving, stranded is called for. Fortunately a overwhelming majority of hookup wire sold is stranded. Example:
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As for gauge/AWG/ga, the laser you indicated has a low current draw…only 0.3 A, So 24 gauge will work just fine even if you need 5 meters of wire. Even 26 or 28 gauge will work fine given this low current.
The laser you indicate appears to use a JST connector, but there is a difference between the various pictures. Some pictures have 4-pin JST connectors, and some pictures have 6-pin JST connectors, so I’m not sure which is used on this module. On the other end of you cable, you are going to need to connect two wires to your power supply. No power supply comes with this laser, but, given the low current draw, you can probably just run it off the 12 power supply for your MPCNC. The third (signal) wire will need to go to your board and likely will need a female Dupont connector. In the indicated module, there is a fourth wire used for temperature, but I’ve never seen that wire used on an MPCNC.
If it were me, I buy a spool (5 - 10 meter) of 3-conductor wire. Wherever you want to buy the wire from, search for ‘3 conductor wire’ or ‘3 pin wire’. Any gauge wire 28 and below (smaller number bigger wire) will work. You will probably find a lot of 22 gauge wire since it is common for led lighting. I’d cut the short cable they send with the laser module solder in my wire to get the length I need.
A couple of things I noticed about the indicated laser module:
- Lasers modules have two power ratings…the number of watts they draw from the power supply and the output power which is sometimes called optical power. The input power tends to be much larger than the output power. The 3500MW is the input power. The output power for this module is likely 500MW. This is enough for engraving but will struggle/fail with most cutting tasks. Places like AliExpress tend to rank their laser models by input power since it makes them seem larger.
- When I switch the language of the page for the indicated laser module to English, some additional information is presented. In particular this is important to know about whatever module you buy: PWM/TTL Input： DC3.3V-12V.
This particular range is very nice and means you might not have to update the firmware.