I've been using some fairly cheap 22AWG wire for running between flexible LED strips and their transformers. Some 24V some 12V, but all well below the amperage rating for this gauge.
The wire says it's rated for 300V / 80ºC. I don't remember what it was sold as. It may even have been sold as speaker wire. It's the type with 2x separate insulated stranded cores.
So far this has all been over the surface and over fairly short distances. (2m or so) but I am now looking at doing a slightly longer run behind a wall. It would run for about 6m and partly would be between brick and skirting board, and in other parts behind plasterboard.
What do I need to consider (mainly with regards to safety and legality) when choosing wire for this job?
Are their specific standards, heat/voltage ratings or particular insulation materials that I should look out for / avoid?
Best Answer
Speaker wire works well for this, and you can get in-wall rated speaker wire, which usually has a 2nd common insulation around both insulated wires (like cat5). You can of course use regular mains-rated wiring in wall, but it's hard to tuck into tight spaces where you might want to hide an LED strip, and connecting to it legally takes a lot of space.
Buy stranded wire with flexible jacket materials like silicone to have an easier time "origami"-ing and hiding. You don't need oxygen free copper or anything fancy. Buy a bigger roll than you need; doubling the length is usually only 25-50% more up-front cost.
In terms of size for LED lighting, 20AWG is a good starting point for typical run lengths and a few watts. Subtract 1 gauge from 20 for every amp (12w/24w) to avoid voltage drop. So, if you need 6 amps, use 14AWG. This correlates decently to the recommended power transmission amp ratings. To be sure, that thickness is overkill in terms of fire safety but it provides voltage consistency to the strips, allowing you to very accurately match/correlate brightness levels by counting strip segments.